
Sampling the $\mu\nu$SSM for displaced decays of the tau left sneutrino LSP at the LHC
arXiv:1907.02092
by: Kpatcha, Essodjolo Abstract: Within the framework of the $\mu\nu$SSM, a displaced dilepton signal is expected at the LHC from the decay of a tau left sneutrino as the lightest supersymmetric particle (LSP) with a mass in the range $45  100$ GeV. We compare the predictions of this scenario with the ATLAS search for longlived particles using displaced lepton pairs in $pp$ collisions, considering an optimization of the trigger requirements by means of a high level trigger that exploits tracker information. The analysis is carried out in the general case of three families of righthanded neutrino superfields, where all the neutrinos get contributions to their masses at tree level. To analyze the parameter space, we sample the $\mu\nu$SSM for a tau left sneutrino LSP with proper decay length $c\tau > 0.1$ mm using a likelihood datadriven method, and paying special attention to reproduce the current experimental data on neutrino and Higgs physics, as well as flavor observables. The sneutrino is special in the $\mu\nu$SSM since its couplings have to be chosen so that the neutrino oscillation data are reproduced. We find that important regions of the parameter space can be probed at the LHC run 3.

Uncertainty in the Reactor Neutrino Spectrum and Mass Hierarchy Determination
arXiv:1907.02309
by: Ciuffoli, Emilio Abstract: One of the challenges that must be overcome in order to determine the neutrino mass hierarchy using reactor neutrinos is the theoretical uncertainty in the unoscillated reactor neutrino spectrum: this is one of the reasons why, recently, it was proposed to add a near detector to the JUNO experiment. A modelindependent treatment of the spectrum uncertainty will be discussed, as well as the effect that it will have on the final result. Moreover, since the neutrino spectrum depends on the chemical composition of the fuel, the spectra at the near and far detectors will be different, because they will receive neutrinos from different cores. Taking into account the time evolution of the chemical composition of the fuel in the reactor core, it is possible to reconstruct the far detector spectrum from the near detector data. We will show that the method used to reconstruct the spectrum can affect sensitivity to the mass hierarchy, however if the near detector is large enough the difference will be negligible.

Effect of polarisation and choice of event generator on spectra from dark matter annihilations
arXiv:1907.02488
by: Niblaeus, Carl Abstract: If indirect detection searches are to be used to discriminate between dark matter particle models, it is crucial to understand the expected energy spectra of secondary particles such as neutrinos, charged antiparticles and gammarays emerging from dark matter annihilations in the local Universe. In this work we study the effect that both the choice of event generator and the polarisation of the final state particles can have on these predictions. For a variety of annihilation channels and dark matter masses, we compare yields obtained with Pythia8 and Herwig7 of all of the aforementioned secondary particle species. We investigate how polarised final states can change these results and do an extensive study of how the polarisation can impact the expected flux of neutrinos from dark matter annihilations in the centre of the Sun. We find that differences between the event generators are larger for yields of hadronic end products such as antiprotons, than for leptonic end products. Concerning polarisation, we conversely find the largest differences in the leptonic spectra. The large differences in the leptonic spectra point to the importance of including polarisation effects in searches for neutrinos from dark matter annihilations in the Sun. However, we find that these differences are ultimately somewhat washed out by propagation effects of the neutrinos in the Sun.

Enhancing Sensitivity to NonStandard Neutrino Interactions at INO combining muon and hadron information
arXiv:1907.02027 IP/BBSR/201903
by: Khatun, Amina Abstract: The neutral current nonstandard interactions (NSI's) of neutrino with matter fermions while propagating through long distances inside the Earth matter can give rise to the extra matter potentials apart from the standard MSW potential due to the $W$mediated interactions in matter. In this paper, we explore the impact of flavor violating neutral current NSI parameter $\varepsilon_{\mu\tau}$ in the oscillation of atmospheric neutrino and antineutrino using the 50 kt magnetized ICAL detector at INO. We find that due to nonzero $\varepsilon_{\mu\tau}$, $\nu_\mu\rightarrow\nu_\mu$ and $\bar\nu_\mu\rightarrow\bar\nu_\mu$ transition probabilities get modified substantially at higher energies and longer baselines, where vacuum oscillation dominates. We estimate the sensitivity of the ICAL detector for various choices of binning schemes and observables. The most optimistic bound on $\varepsilon_{\mu\tau}$ that we obtain is $0.01 < \varepsilon_{\mu\tau} < 0.01 $ at 90$\%$ C.L. using 500 kt$\cdot$yr exposure and considering $E_\mu,\, \cos\theta_\mu,\,E'_{\rm had}$ as observables in their ranges [1, 21] GeV, [1, 1], and [0, 25] GeV respectively. For the first time we show that the charge identification capability of the ICAL detector is crucial to set stringent constraints on $\varepsilon_{\mu\tau}$. We also show that when we marginalize over $\varepsilon_{\mu\tau}$ in fit in its range of 0.1 to 0.1, the mass hierarchy sensitivity deteriorates by 10$\%$ to 20$\%$ depending on the analysis mode, and the precision measurements of atmospheric parameters remain quite robust at the ICAL detector.

Neutrino oscillations and instabilities in degenerate relativistic astrophysical plasmas
Phys.Rev. E99 (2019) 063209
by: Haas, Fernando (Rio Grande do Sul U.)
Abstract: We set up a proposal to extend significantly recent works on neutrinoplasma interaction, allowing the possibility of deep degenerate and relativistic electrons, which are often present in compact stars such as highdensity white dwarfs. The methodology involves the covariant hydrodynamic formulation of ultradense plasmas. We propose the generalization of previous studies, on the interaction between ionacoustic waves and resonant neutrino flavor oscillations in a mixed neutrino beam, admitting degenerate and relativistic electron populations. Destabilization of the ion acoustic wave has higher growth rates, thanks to the very high densities present in plasmas under these extreme conditions. We take into account applications to white dwarf stars in the process of collapsing, producing type II supernovas.

Neutrino Masses and Mixing from Double Covering of Finite Modular Groups
USTCICTS1917 arXiv:1907.01488
by: Liu, XiangGan Abstract: We extend the even weight modular forms of modular invariant approach to general integral weight modular forms. We find that the modular forms of integral weights and level $N$ can be arranged into irreducible representations of the homogeneous finite modular group $\Gamma'_N$ which is the double covering of $\Gamma_N$. The lowest weight 1 modular forms of level 3 are constructed in terms of Dedekind etafunction, and they transform as a doublet of $\Gamma'_3 \cong T'$. The modular forms of weights 2, 3, 4, 5 and 6 are presented. We build a model of lepton masses and mixing based on $T'$ modular symmetry.

Neutrino Masses from the Point of View of Economy and Simplicity
arXiv:1907.01472
by: Bilenky, S. Abstract: In the framework of such basic principles as local gauge invariance, unification of the weak and electromagnetic interactions and spontaneous symmetry breaking in the Standard Model the most economical and simplest possibilities are realized. We discuss the problem of neutrino masses from the point of view of economy and simplicity. It is unlikely that neutrino masses are of the same SM origin as masses of leptons and quarks. The Weinberg effective Lagrangian is the simplest and the most economical, beyond the Standard Model mechanism of the generation of small Majorana neutrino masses. The resolution of the sterile neutrino anomaly and observation of the neutrinoless double $\beta$decay would be crucial tests of this mechanism.

Probing NonStandard Neutrino Interactions with Supernova Neutrinos at HyperK
arXiv:1907.01059
by: Lei, Minjie Abstract: Nonstandard neutrino self interactions (NSSI) could be stronger than Fermi interactions. We investigate the ability to constrain these fourneutrino interactions by their effect on the flux of neutrinos originating from a galactic supernova. In the dense medium of a core collapse supernova, these new self interactions can have a significant impact on neutrino oscillations, leading to changes at the flavor evolution and spectra level. We use simulations of the neutrino flux from a 13 solar mass, core collapse supernova at 10 kpc away, and numerically propagate these neutrinos through the stellar medium taking into account vacuum/MSW oscillations, SM $\nu\nu$ scattering as well as $\nu\nu$ interactions that arise from NSSI. We pass the resulting neutrino flux to a simulation of the future HyperKamiokande detector to see what constraints on NSSI parameters are possible when the next galactic supernova becomes visible. We find that these constraints depend strongly on the neutrino mass hierarchy and if the NSSI is flavorviolating or preserving. Sensitivity to NSSI in the normal hierarchy (NH) at HyperK is limited by the experiment's ability to efficiently detect $\nu_{e}$, but deviations from no NSSI could be seen if the NSSI is particularly strong. In the inverted hierarchy (IH) scenario, HyperK can significantly improve constraints on flavorviolating NSSI down to $\mathcal{O}(10^{1})G_{F}$.

Study of a tridirect littlest seesaw model at MOMENT
arXiv:1907.01371
by: Tang, Jian Abstract: The tridirect littlest seesaw model (TDLS) has been proposed, and succeeds in explaining the current global fit results with only four degrees of freedom. This model can be tested by the future experiments that improve the precision of neutrino mixing parameters, \textit{such as} the MuOndecay MEdium baseline NeuTrino beam experiment (MOMENT). In this work, we study how much MOMENT can extend our knowledge on the TDLS model. We find that measurements of $\theta_{23}$ and $\delta$ are crucial for MOMENT to exclude the model at more than $5\sigma$ confidence level, if the best fit values in the last global analysis result is confirmed. Moreover, the $3\sigma$ precision of model parameters can be improved at MOMENT by at least a factor of two. Finally, we project the surface at the $3\sigma$ confidence level from the modelparameter space to the oscillationparameter space, and find the potential of MOMENT to observe the sum rule between $\theta_{23}$ and $\delta$ predicted by TDLS.

QuasiDirac neutrino oscillations at DUNE and JUNO
arXiv:1907.00980
by: Anamiati, G. Abstract: QuasiDirac neutrinos are obtained when the Lagrangian density of a neutrino mass model contains both Dirac and Majorana mass terms, and the Majorana terms are sufficiently small. This type of neutrinos introduces new mixing angles and mass splittings into the Hamiltonian, which will modify the standard neutrino oscillation probabilities. In this paper, we focus on the case where the new mass splittings are too small to be measured, but new angles and phases are present. We perform a sensitivity study for this scenario for the upcoming experiments DUNE and JUNO, finding that they will improve current bounds on the relevant parameters. Finally, we also explore the discovery potential of both experiments, assuming that neutrinos are indeed quasiDirac particles.

Neutrino oscillations at dual baselines
arXiv:1907.01185
by: Cho, Minseok Abstract: Beam neutrino oscillation experiments typically employ only one detector at a certain baseline, apart from the near detector that measures the unoscillated neutrino flux at the source. Lately, there have been discussions of having detectors at two different baselines in one of the future longbaseline neutrino oscillation experiments. We study the potential advantage of a general dualbaseline system and perform analysis with a specific example of the envisioned T2HKK experiment. We introduce a new parameter to exploit the correlation between the oscillations at both baselines, and show how it can help in determining the mass hierarchy and the CP phase in the neutrino sector. Our study and findings can be generically used for any dualbaseline system.

Neutrino NonStandard Interactions: A Status Report
arXiv:1907.00991 FERMILABCONF19299T
by: Bhupal Dev, P.S. (McDonnell Ctr. Space Sci.) et al.
Abstract: This report summarizes the present status of neutrino nonstandard interactions (NSI). After a brief overview, several aspects of NSIs are discussed, including connection to neutrino mass models, modelbuilding and phenomenology of large NSI with both light and heavy mediators, NSI phenomenology in both short and longbaseline neutrino oscillation experiments, neutrino crosssections, complementarity of NSI with other low and highenergy experiments, fits with neutrino oscillation and scattering data, DUNE sensitivity to NSI, effective field theory of NSI, as well as the relevance of NSI to dark matter and cosmology. We also discuss the open questions and interesting future directions that can be pursued by the community at large. This report is based on talks and discussions during the Neutrino Theory Network NSI workshop held at Washington University in St. Louis from May 2931, 2019 (https://indico.cern.ch/event/812851/)

Electroweak pionproduction on nuclei within the extended factorization scheme
arXiv:1907.01093 FERMILABPUB19305T
by: Rocco, Noemi (Argonne, PHY) et al.
Abstract: We have applied the extended factorization scheme to investigate the electroweak pion production on nuclei. The ANLOsaka model, which was obtained by analyzing the data of $\pi N$, $\gamma N$, $N(e,e'\pi)$ and $N(\nu,\mu\,\pi) $ reactions up to invariant mass $W=$ 2 GeV, is used to generate the matrix elements of current operators relevant to pionproduction off the nucleon. Medium effects on the $\Delta$ (1232) component of mesonexchange current are included by using a $\Delta$nucleus potential determined from the previous $\Delta$hole model studies of pionnucleus reactions. Nuclear correlations in the initial target state and in the spectator system(s) are modeled using realistic hole spectral functions. As a first step, we show that the data of $^{12}$C$(e,e')$ up to the $\Delta$ (1232) region can be described reasonably well. The interplay between the pion production and twobody mesonexchange mechanisms is shown to be essential in improving the agreement with the data in the ``dip'' region, between the quasielastic and the $\Delta$ (1232) peaks. Predictions for $^{12}$C$(\nu,\mu\,\pi)$ have also been made. They can be used to estimate pionemission rates in neutrinonucleus cross section, which constitutes an important systematic uncertainty to the reconstructed neutrino energy. With further improvements of the Metropolis MonteCarlo techniques to account for final states comprised of more than two particles, our approach can be employed up to $W=$ 2 GeV, where twopion production and higher mass nucleon resonances must be included for analyzing the data from acceleratorbased neutrinooscillation experiments.

Cosmological Unification, Dark Energy and the Origin of Neutrino Mass
arXiv:1907.00131
by: SalazarArias, J.G. Abstract: We suggest that quintessential vacuum energy could be the source of right handed neutrino masses that feed the seesaw mechanism, which may provide observed small masses to light standard neutrinos. This idea is naturally implemented in the Cosmological Unification model based on the global $SO(1,1)$ symmetry, where early inflation and late accelerated expansion of the Universe are driven by the degrees of freedom of a doublet scalar field. In this model, the $SO(1,1)$ custodial symmetry naturally provides the quintessence to standard model singlet fermion couplings that source neutrino masses. We also show that the model predicts a highly suppressed contribution to relativistic degrees of freedom from quintessential quanta at any late Universe epoch, ensuring the consistency of the model.

Forecast for weighing neutrinos in cosmology with SKA
arXiv:1907.00179
by: Zhang, JingFei Abstract: We investigate what role the SKA neutral hydrogen sky survey observation will play in weighing neutrinos in cosmology. We use the simulated data of the baryon acoustic oscillation (BAO) measurements from the neutral hydrogen survey based on SKA1 and SKA2 to do the analysis. For the current observations, we use the {\it Planck} 2015 cosmic microwave background (CMB) anisotropies observation, the BAO measurements, the type Ia supernovae (SN) observation (Pantheon compilation), and the latest $H_0$ measurement. We consider three mass ordering cases for massive neutrinos, i.e., the normal hierarchy (NH), inverted hierarchy (IH), and degenerate hierarchy (DH) cases. It is found that the SKA observation can significantly improve the constraints on $\Omega_{\rm m}$ and $H_0$. Compared to the current observation, the SKA1 data can improve the constraints on $\Omega_{\rm m}$ by about 33%, and on $H_0$ by about 36%; the SKA2 data can improve the constraints on $\Omega_{\rm m}$ by about 58%, and on $H_0$ by about 66%. It is also found that the SKA observation can only slightly improve the constraints on $\sum m_\nu$. Compared to the current observation, the SKA1 data can improve the constraints on $\sum m_\nu$ by about 4%, 3%, and 10%, for the NH, IH, and DH cases, respectively; the SKA2 data can improve the constraints on $\sum m_\nu$ by about 7%, 7%, and 16%, for the NH, IH, and DH cases, respectively.

Borexino and General Neutrino Interactions
arXiv:1906.12102
by: Khan, Amir N. Abstract: We derive constraints on all possible general neutrinoelectron interactions (scalar, vector, pseudoscalar, axialvector and tensor) using the recent real time Borexino event rate measurements of $pp$, $pep$ and $^{7}Be$ solar neutrinos. The limits improve several previous ones from TEXONO and CHARMII for incoming electron and muon neutrinos, and are the first ones for the tau flavor. Future improvements by nextgeneration solar neutrino experiments are also studied. The limits extend the physics reach of solar neutrino measurements to TeVscale physics. Finally, the different properties of the new interactions for Dirac and Majorana neutrinos are discussed.

Neutrino decoherence in presence of strong gravitational fields
arXiv:1906.12152
by: Chatelain, Amélie (APC, Paris) et al.
Abstract: We explore the impact of strong gravitational fields on neutrino decoherence. To this aim, we employ the density matrix formalism to describe the propagation of neutrino wave packets in curved spacetime. By considering Gaussian wave packets, we determine the coherence proper time, neglecting the effect of matter outside the compact object. We show that strong gravitational fields nearby compact objects significantly influence neutrino coherence.

Statistical Methods for the Search of Sterile Neutrinos
arXiv:1906.11854
by: Agostini, Matteo Abstract: The statistical methods applied to search for shortbaseline neutrino oscillations induced by a sterile neutrino with mass at the eV scale are reviewed and compared. The comparison is performed under limit setting and signal discovery scenarios, considering both when an oscillation would enhance the neutrino interaction rate in the detector and when it would reduce it. The sensitivity of the experiments and the confidence regions extracted for specific data sets are found to change significantly according to the test statistic used for the hypothesis testing. The most general test statistic does not make assumptions on the value of the parameters of interest for the analysis, while the others restrict the allowed parameter space. The restriction of the parameter space could lead to miss a signal or, vice versa, to claim a discovery when this is not statistically significant. Similar issues are found also when the validity of Wilks' theorem is assumed. A standardized analysis approach based on the most general kind of hypothesis test is proposed.

Testability of leptogenesis with three RHneutrinos below the electroweak scale
arXiv:1906.11869 CP31932
by: Lucente, Michele Abstract: The Standard Model extended with righthanded neutrinos whose masses are below the electroweak scale provides a simultaneous solution for the origin of neutrino masses and of the baryon asymmetry of the Universe, that can be tested in current experiments. If three righthanded neutrinos participate to the processes, their parameter space of solutions extends to very large mixing angles, saturating the current experimental constraints. Solutions with righthanded neutrino masses at the GeV scale can be probed in the decay of $B$ mesons at the LHC. For this channel the collision of isotopes of intermediate mass such as Ar provides a better sensitivity per unit of running time compared to collisions with protons.

Low scale leptogenesis in a hybrid model of the scotogenic type I and III seesaw
arXiv:1906.12008 KANAZAWA1904
by: Suematsu, Daijiro Abstract: The scotogenic type I and type III seesaw models are good candidates to explain the existence of neutrino masses and dark matter simultaneously. However, since triplet fermions have SU(2) gauge interaction, they cannot be out of equilibrium before the electroweak symmetry breaking. Thus, leptogenesis seems to be difficult within a framework of the pure type III seesaw model. Some extension seems to be required to solve this fault. A model extended by introducing a singlet fermion could be such a simple example. If the singlet fermion is in the thermal equilibrium even for its extremely small neutrino Yukawa coupling, leptogenesis could be shown to occur successfully for a rather low mass of the singlet fermion. The required mass could be lowered to $10^4$~GeV.

A New Littlest Seesaw Model
arXiv:1906.11414 USTCICTS1915
by: Chen, PingTao (Hefei, CUST) et al.
Abstract: We propose and discuss a new Littlest Seesaw model, realised in the tridirect CP approach, in which the couplings of the two righthanded neutrinos to the lepton doublets are proportional to $(0,1,1)$ and $(1,5/2,1/2)$ respectively with the relative phase $\eta=\pi/2$. This model can give an excellent description of lepton flavour mixing, including an atmospheric neutrino mixing angle in the second octant, in terms of only two input parameters. We show that the observed baryon asymmetry can be generated for the lightest righthanded neutrino mass $M_{1}=1.176\times 10^{11}$ GeV in SM and $M_{1}=3.992\times 10^{10}$ GeV in MSSM with $\tan\beta=5$. We construct an explicit Littlest Seesaw model based on the flavour symmetry $S_4\times Z_4\times Z_9$ in which the desired alignments and the phase $\eta=\pi/2$ are achieved.

Comparative Analysis of CP Violation in the Exponential and Standard Parametrizations of the Neutrino Mixing Matrix
Phys.Atom.Nucl. 82 (2019) 281290
by: Davydova, A.A. (Moscow State U.) et al.
Abstract: A comparative analysis of neutrino mixing in the standard, cobimaximal, tribimaximal, and exponential parametrizations is performed. The logarithm of the mixing matrix and exact values for the entries of the exponential neutrino mixing matrix, which permits factorizing in it terms responsible for pure rotation and CP violation, are found with allowance for the most recent experimental data on neutrino mixing. The hypothesis of complementarity of quark and neutrino mixing is confirmed. The dependence of CP violation on the parameters of the mixing matrix in various parametrizations is studied with the aid of the Jarlskog invariant, and underlying relations between these parameters are also revealed. The representation of the mixing matrix in the exponential parametrization as an SU(3) matrix element by employing the parameters φ and θ and their dependence on the amount of CP violation is considered.

Anomalous ANITA air shower events and tau decays
arXiv:1906.11736
by: Chipman, Shoshana (Chicago U., Astron. Astrophys. Ctr.) et al.
Abstract: Two unusual neutrino events in the Antarctic Impulse Transient Antenna (ANITA) appear to have been generated by air showers from a particle emerging from the Earth at angles 2535 degrees above the horizon. We evaluate the effective aperture for ANITA with a simplified detection model to illustrate the features of the angular dependence of expected events for incident standard model tau neutrinos and for sterile neutrinos that mix with tau neutrinos. We apply our sterile neutrino aperture results to a dark matter scenario with longlived supermassive dark matter that decay to sterile neutrinolike particles. We find that for upgoing air showers from tau decays, from isotropic fluxes of standard model, sterile neutrinos or other particles that couple to the tau through suppressed weak interaction cross sections cannot be responsible for the unusual events.

PatiSalam unification with a spontaneous $CP$ violation
arXiv:1906.10849 KANAZAWA1903
by: Suematsu, Daijiro (Kanazawa U., Inst. Theor. Phys.)
Abstract: Recent neutrino oscillation experiments suggest that the PMNS matrix in the lepton sector has a $CP$ violating phase as the CKM matrix in the quark sector. However, origin of these phases in both matrices are not clarified by now. Although complex Yukawa couplings could induce these phases, they remain as free parameters of the model even in that case. If the $CP$ symmetry is considered to be spontaneously broken, they are expected to be determined by some physics at a much lower energy scale than the Planck scale. We study such a possibility in a framework of PatiSalam type unification. We also discuss other phenomenological issues in it.

Kinetic mixing effect in noncommutative $BL$ gauge theory
arXiv:1906.10577
by: Van Loi, Duong (Phenikaa U., Hanoi) et al.
Abstract: It is well established that the $SU(P)_L$ gauge symmetry for $P\geq 3$ can address the question of fermion generation number due to the anomaly cancellation, but it neither commutes nor closes algebraically with electric and baryonminuslepton charges. Hence, two $U(1)$ factors that determine such charges are required, yielding a complete gauge symmetry, $SU(P)_L\otimes U(1)_X\otimes U(1)_N$, apart from the color group. The resulting theory manifestly provides neutrino mass, dark matter, inflation, and baryon asymmetry of the universe. Furthermore, this gauge structure may present kinetic mixing effects associated to the $U(1)$ gauge fields, which affect the electroweak precision test such as the $\rho$ parameter and $Z$ couplings as well as the new physics processes. We will construct the model, examine the interplay between the kinetic mixing and those due to the symmetry breaking, and obtain the physical results in detail.

Modular $S_3$ invariant flavor model in SU(5) GUT
arXiv:1906.10341 EPHOU19008 and HUPD1907
by: Kobayashi, Tatsuo (Hokkaido U.) et al.
Abstract: We present the flavor model with the $S_3$ modular invariance in the framework of SU(5) GUT. The $S_3$ modular forms of weights $2$ and $4$ give the quark and lepton mass matrices with a common complex parameter, the modulus $\tau$. The GUT relation of downtype quarks and charged leptons is imposed by the VEV of adjoint 24dimensional Higgs multiplet in addition to the VEVs of $5$ and $\bar 5$ Higgs multiples of SU(5). The observed CKM and PMNS mixing parameters as well as the mass eigenvalues are reproduced properly. We predict the leptonic CP phase and the effective mass of the neutrinoless double beta decay versus the sum of neutrino masses.

MultiMessenger Astrophysics
arXiv:1906.10212
by: Mészáros, Péter (Penn State U., Astron. Astrophys.) et al.
Abstract: Multimessenger astrophysics, a longanticipated extension to traditional and multiwavelength astronomy, has recently emerged as a distinct discipline providing unique and valuable insights into the properties and processes of the physical universe. These insights arise from the inherently complementary information carried by photons, gravitational waves, neutrinos, and cosmic rays about individual cosmic sources and source populations. Realizing the observation of astrophysical sources via nonphotonic messengers has presented enormous challenges, as evidenced by the fiscal and physical scales of the multimessenger observatories. However, the scientific payoff has already been substantial, with even greater rewards promised in the years ahead. In this review we survey the current status of multimessenger astrophysics, highlighting some exciting recent results, and addressing the major followon questions they have raised. Key recent achievements include the measurement of the spectrum of ultrahigh energy cosmic rays out to the highest observable energies; discovery of the diffuse high energy neutrino background; the first direct detections of gravitational waves and the use of gravitational waves to characterize merging black holes and neutron stars in strongfield gravity; and the identification of the first joint electromagnetic + gravitational wave and electromagnetic + highenergy neutrino multimessenger sources. We then review the rationales for the next generation of multimessenger observatories, and outline a vision of the most likely future directions for this exciting and rapidly advancing field.

Dark matter mass from relic abundance, extra $U(1)$ Gauge boson and ActiveSterile Neutrino Mixing
arXiv:1906.10185
by: Bhat, Imtiyaz Ahmad (Jamia Millia Islamia) et al.
Abstract: In a model with extra $U(1)$ gauge to Standard Model gauge group we have shown the allowed region of masses of extra gauge boson and the dark matter which is the lightest one among other righthanded Majorana fermions present in the model. To obtain this region we have used bound on dark matter relic density obtained by PLANCK together with the bound on extra gauge boson mass and its gauge coupling recently obtained by ATLAS collaboration at LHC. This allowed region also get further constrained by the required activesterile neutrino mass and mixing present in the model. The requirement of light active neutrino mass around 0.1 eV scale requires dark matter mass around TeV scale. We have discussed how the coannihilation channel of dark matter with next heavier righthanded Majorana fermion and their mass gap change the allowed region. For fixed extra $U(1)$ gauge boson mass and gauge coupling we have shown that for any particular relic density within PLANCK bound there are in general two possible solutions of dark matter mass.

Hints of Sterile Neutrinos in Recent Measurements of the Hubble Parameter
arXiv:1906.10136 IPMU190090
by: Gelmini, Graciela B. (UCLA) et al.
Abstract: Local Universe observations find a value of the Hubble constant $H_0$ that is larger than the value inferred from the Cosmic Microwave Background and other early Universe measurements, assuming known physics and the $\Lambda$CDM cosmological model. We show that additional radiation in active neutrinos produced just before Big Bang Nucleosynthesis by an unstable sterile neutrino with mass $m_s=$ O(10) MeV can alleviate this discrepancy. The necessary masses and couplings of the sterile neutrino, assuming it mixes primarily with $\nu_{\tau}$ and/or $\nu_{\mu}$ neutrinos, are within reach of SuperKamiokande as well as upcoming laboratory experiments such as NA62.

Radiatively scotogenic typeII seesaw and a relevant phenomenological analysis
arXiv:1906.10516
by: Chen, ChuanHung (Taiwan, Natl. Cheng Kung U.) et al.
Abstract: When a small vacuum expectation value of Higgs triplet ($v_\Delta$) in the typeII seesaw model is required to explain neutrino oscillation data, a finetuning issue occurs on the massdimension leptonnumberviolation (LNV) scalar coupling. Using the scotogenic approach, we investigate how a small LNV term is arisen through a radiative correction when an $Z_2$odd vectorlike lepton ($X$) and an $Z_2$odd righthanded Majorana lepton ($N$) are introduced to the typeII seesaw model. Due to the dark matter (DM) direct detection constraints, the available DM candidate is the righthanded Majorana particle, whose mass depends on and is close to the $m_X$ parameter. Combing the constraints from the DM measurements, the $h\to \gamma\gamma$ decay, and the oblique $T$parameter, it is found that the preferred range of $v_\Delta$ is approximately in the region of $10^{5}10^{4}$ GeV; the mass difference between the doubly and the singly charged Higgs is less than 50 GeV, and the influence on the $h\to Z\gamma$ is not significant. Using the constrained parameters, we analyze the decays of each Higgs triplet scalar in detail, including the possible threebody decays when the kinematic condition is allowed. It is found that with the exception of doubly charged Higgs, scalar mixing effects play an important role in the Higgs triplet twobody decays when the scalar masses are neardegenerate. In the nondegenerate mass region, the branching ratios of the Higgs triplet decays are dominated by the threebody decays.

Dynamical coupledchannels approach to electroweak meson productions on nucleon and deuteron
arXiv:1906.10351
by: Nakamura, Satoshi X. (Hefei, CUST)
Abstract: I overview our recent activity with the ArgonneOsaka dynamical coupledchannels (DCC) approach that provides a unified description of various electroweak meson productions on single nucleon and nucleus. First I discuss the DCC model of a single nucleon. The DCC model has been developed through a comprehensive analysis of $\pi N, \gamma N\to \pi N, \eta N, K\Lambda, K\Sigma$ reaction data. The model has been further extended to finite $Q^2$ region by analyzing pion electroproduction data, and to neutrinoinduced reactions using the PCAC relation. Next I discuss applications of the DCC model to electroweak meson productions on the deuteron. We consider impulse mechanism supplemented by final state interactions (FSI) due to $NN$ and mesonnucleon rescatterings. Using this model, I discuss FSI corrections needed to extract $\gamma$neutron reaction observables from $\gamma d\to \pi NN$, and a novel method to extract $\eta N$ scattering length from $\gamma d\to \eta pn$. I also discuss FSI corrections on the existing neutrinonucleon pion production data that had been extracted from neutrinodeuteron data.

BigBang Nucleosynthesis and Primordial Lithium Abundance Problem
arXiv:1708.05567 J.Exp.Theor.Phys. 128 (2019) 707712 J.Exp.Theor.Phys. 155 (2019) 832838
by: Singh, V. (Calcutta, VECC) et al.
Abstract: Prediction of the primordial abundances of elements in the bigbang nucleosynthesis (BBN) is one of the three strong evidences for the big bang model. Precise knowledge of the baryontophoton ratio of the Universe from observations of the anisotropies of cosmic microwave background radiation has made the Standard BBN a parameterfree theory. Although, there is a good agreement over a range of nine orders of magnitude between abundances of light elements deduced from observations and calculated in primordial nucleosynthesis, there remains a yetunexplained discrepancy of$^{7}$Li abundance higher by a factor of ~3 when calculated theoretically. The primordial abundances depend on the astrophysical nuclear reaction rates and on three additional parameters, the number of light neutrino flavors, the neutron lifetime and the baryontophoton ratio in the Universe. The effect of the modification of thirtyfive reaction rates on light element abundance yields in BBN was investigated earlier by us. In the present work we have incorporated the most recent values of neutron lifetime and the baryontophoton ratio and further modified$^{3}$He($^{4}$He, γ)$^{7}$Be reaction rate which is used directly for estimating the formation of$^{7}$Li as a result of β$^{+}$ decay as well as the reaction rates for t($^{4}$He,γ)$^{7}$Li and d($^{4}$He,γ)$^{6}$Li. We find that these modifications reduce the theoretically calculated abundance of$^{7}$Li by ~12%.

Neutrino flavor oscillations and spin rotation in matter and electromagnetic field
arXiv:1906.09351
by: Chukhnova, A.V. (Moscow State U.) et al.
Abstract: We obtain an evolution equation for neutrinos in dense matter and electromagnetic field, which describes both flavor oscillations and neutrino spin rotation. Using this equation we construct a quasiclassical theory of these phenomena. We obtain the probabilities of arbitrary spinflavor transitions assuming the external conditions to be constant. We demonstrate that the resonance behavior of the transition probabilities is possible only when the flavor neutrino states cannot be described as superpositions of the mass eigenstates. We discover that a resonance, which is similar to the MikheevSmirnov resonance, takes place for neutrinos in magnetic field due to the transition magnetic moments.

Neutrino currents in wakes of cosmic strings
arXiv:1906.09733
by: Sau, Sovan (Hyderabad U.) et al.
Abstract: Neutrinos rotating around Abelian Higgs strings will generate a neutral current close to the string. As the string moves through the cosmic plasma, the velocity kick generated by the motion of the string will enhance the neutrino current in the wake region. The neutrino current density depends on its distance from the string and is oscillatory in nature. This leads to neutrino density gradients in the plasma. Such a flux of neutrinos with periodic density fluctuations will lead to electron currents in the plasma. The current will act like a crossperturbation across the cosmic string wake. The perturbation as well as the high Reynolds number of the plasma will result in the generation of magnetic fields in the wake of the cosmic string.

SingletDoublet Dirac Dark Matter and Neutrino Masses
arXiv:1906.09685
by: Restrepo, Diego (Antioquia U.) et al.
Abstract: We examine an extension of the Standard Model that addresses the dark matter puzzle and generates Dirac neutrinos masses through the radiative seesaw mechanism. The new field content includes a scalar field that plays an important role in setting the relic abundance of dark matter. We analyze the phenomenology in the light of direct, indirect, and collider searches of dark matter. In this framework, the dark matter candidate is a Dirac particle that is a mixture of new singletdoublet fields with mass $m_{\chi_1^0}\lesssim 1.1\,\text{TeV}$. We find that the allowed parameter space of this model is broader than the wellknown Majorana dark matter scenario.

Neutrino spinflavor oscillations in solar environment
arXiv:1906.09475
by: Joshi, Sandeep (Bhabha Atomic Res. Ctr.) et al.
Abstract: We study the phenomena of neutrino spinflavor oscillations due to solar magnetic fields. This allows us to examine how significantly the electron neutrinos produced in the solar interior undergo a resonant spinflavor conversion. We construct analytical models for solar magnetic field in all the three regions of the Sun. Neutrino spinflavor oscillations in these magnetic field is examined by studying the level crossing phenomena and comparing the two cases of zero and nonzero vacuum mixing respectively. It is shown that including the effect of nonzero vacuum mixing angle leads to suppression of neutrinoantineutrino transition. Related phenomena such as effects of matter on neutrino spin transitions and differences between Dirac and Majorana transitions in the solar magnetic fields are also discussed.

Exploring CPViolating heavy neutrino oscillations in rare tau decays at Belle II
arXiv:1906.09470
by: Tapia, Sebastian (Illinois U., Urbana) et al.
Abstract: In this work, we study the lepton number violating tau decays via two intermediate onshell Majorana neutrinos $N_j$ into two charged pions, and a charged lepton $\tau^{\pm} \to \pi^{\pm} N_j \to \pi^{\pm} \pi^{\pm} \ell^{\mp}$. We consider the scenario where the heavy neutrino masses are within $0.5$ GeV $\leq M_N \leq 1.5$ GeV. We evaluated the possibility to measure the modulation of the decay width along the detector length for these processes at taus factories, such as Belle II. We study some realistic conditions which could lead to the observation of this phenomenon at futures $\tau$'s factories.

Highlights from the 7 year High Energy Starting Event sample in Icecube
arXiv:1906.09623
by: Farrag, Kareem (Queen Mary, U. of London)
Abstract: Here we outline the main highlights from the 7 year High Energy Starting Events (HESE) event sample. The next new physics search using astrophysical neutrino flavor data is described, where we reach the Planck scale for the first time.

Test of Lorentz Violation with Astrophysical Neutrino Flavor in IceCube
arXiv:1906.09240
by: Katori, Teppei (Queen Mary, U. of London) et al.
Abstract: Astrophysical highenergy neutrinos observed by IceCube are sensitive to small effects in a vacuum such as those motivated from quantum gravity theories. Here, we discuss the potential sensitivity of Lorentz violation from the diffuse astrophysical neutrino data in IceCube. The estimated sensitivity reaches the Planck scale physics motivated region, providing IceCube with real discovery potential of Lorentz violation.

New partial symmetries from group algebras for lepton mixing
arXiv:1906.09157
by: Rong, ShuJun (Guilin U. Technol.)
Abstract: Recent stringent experiment data of neutrino oscillations induces partial symmetries such as $Z_{2}$, $Z_{2}\times CP$ to derive lepton mixing patterns. New partial symmetries expressed with elements of group algebras are studied. A specific lepton mixing pattern could correspond to a set of equivalent elements of a group algebra. And the transformation which interchanges the elements could express a residual $CP$ symmetry. Lepton mixing matrices from $S_{3}$ group algebras are of the trimaximal form with the $\mu\tau$ reflection symmetry. Accordingly, elements of $S_{3}$ group algebras are equivalent to $Z_{2}\times CP$. Comments on $S_{4}$ group algebras are given. And the predictions of $Z_{2}\times CP$ broken from the group $S_{4}$ with the generalized $CP$ symmetry are also obtained from elements of $S_{4}$ group algebras.

Fast Neutrino Flavor Conversion: Collective Motion vs. Decoherence
arXiv:1906.08794 MPP2019120
by: Capozzi, Francesco (Munich, Max Planck Inst.) et al.
Abstract: In an interacting neutrino gas, flavor coherence becomes dynamical and can propagate as a collective mode. In particular, tachyonic instabilities can appear, leading to "fast flavor conversion" that is independent of neutrino masses and mixing angles. On the other hand, without neutrinoneutrino interaction, a prepared wave packet of flavor coherence simply dissipates by kinematical decoherence of infinitely many noncollective modes. We reexamine the dispersion relation for fast flavor modes and show that for any wavenumber,there exists a continuum of noncollective modes besides a few discrete collective ones. So for any initial wave packet, both decoherence and collective motion occurs, although the latter typically dominates for a sufficiently dense gas. We derive explicit eigenfunctions for both collective and noncollective modes. If the angular mode distribution of electronlepton number crosses between positive and negative values, two noncollective modes can merge to become a tachyonic collective mode. We explicitly calculate the interaction strength for this critical point. As a corollary we find that a single crossing always leads to a tachyonic instability. For an even number of crossings, no instability needs to occur.

LHC sensitivity to singlycharged scalars decaying into electrons and muons
arXiv:1906.08685
by: Alcaide, Julien (Valencia U.) et al.
Abstract: Current LHC searches for nonsupersymmetric singlycharged scalars, based on TwoHiggsDoublet models, in general focus the analysis on thirdgeneration fermions in the final state. However, singlycharged scalars in alternative extensions of the scalar sector involve Yukawa couplings not proportional to the mass of the fermions. Assuming the scalar decays into electrons and muons, it can manifest cleaner experimental signatures. In this paper we suggest that a singlycharged scalar singlet, with electroweak production, can start to be probed in the near future with dedicated search strategies. Depending on the strength of the Yukawa couplings, two independent scenarios are considered: direct pairproduction (small couplings) and singleproduction via virtual neutrino exchange (large couplings). We show that, up to a mass as large as 500 GeV, most of the parameter space could be excluded at the 95% C.L. in a highluminosity phase of the LHC. Our results also apply to other frameworks, provided the singlycharged scalar exhibits similar production patterns and dominant decay modes.

Cosmology with a Master Coupling in Flipped SU(5) $\times$ U(1): The $\lambda_6$ Universe
arXiv:1906.08483 KCLPHTH/201952 CERNTH2019096 UT1914 ACT0419, MITH1924 UMNTH3827/19 FTPIMINN19/18
by: Ellis, John (King's Coll. London) et al.
Abstract: We propose a complete cosmological scenario based on a flipped SU(5) $\times$ U(1) GUT model that incorporates Starobinskylike inflation, taking the subsequent cosmological evolution carefully into account. A single master coupling, $\lambda_6$, connects the singlet, GUT Higgs and matter fields, controlling 1) inflaton decays and reheating, 2) the gravitino production rate and therefore the nonthermal abundance of the supersymmetric cold dark matter particle, 3) neutrino masses and 4) the baryon asymmetry of the Universe.

POEMMA's Target of Opportunity Sensitivity to Cosmic Neutrino Transient Sources
arXiv:1906.07209
by: Venters, Tonia M. (NASA, Goddard) et al.
Abstract: We calculate the sensitivity of spacebased cosmic neutrino detection from transient sources in the context of the Probe Of Extreme MultiMessenger Astrophysics (POEMMA) mission using TargetofOpportunity (ToO) observations. POEMMA uses two spacecraft each with a large Schmidt telescope to simultaneously view the optical signals generated by extensive air showers (EASs). POEMMA is designed for both ultrahighenergy cosmic ray and veryhighenergy neutrino measurements. POEMMA has significant neutrino sensitivity starting in the 10 PeV decade via measurements of Cherenkov signals from upwardmoving EASs initiated by tau neutrinos interacting in the Earth. For ToO observations, POEMMA uses the ability to quickly repoint ($90^\circ$ in 500 s) each of the two spacecraft to the direction of the transient source. POEMMA EAS measurements are performed during astronomical night, leading to different observational constraints for short and longduration bursts. For shortbursts of order $10^3$ s, POEMMA will increase the sensitivity of existing experiments (e.g., IceCube and the Pierre Auger Observatory) by up to two orders of magnitude. For longduration bursts on the scale of $10^{56}$ s, the full celestial sky is available and the average neutrino sensitivity will be increased by up to a factor of 50, reaching the desired level to probe model predictions of transient neutrino sources (e.g., of blazar flares as well as both black holeblack hole and neutron starneutron star mergers). POEMMA's neutrino sensitivity to various models of transient neutrino sources are detailed. Altogether, our results demonstrate better sensitivity to ToO neutrino sources from the spacebased POEMMA experiment compared to current groundbased experiments, and more importantly, demonstrate unique fullsky coverage for ToO neutrino sources.

Inflation, Proton Decay, and HiggsPortal Dark Matter in $SO(10) \times U(1)_\psi$
arXiv:1906.06869
by: Okada, Nobuchika (Alabama U.) et al.
Abstract: We propose a simple nonsupersymmetric grand unified theory (GUT) based on the gauge group $SO(10) \times U(1)_\psi$. The model includes 3 generations of fermions in ${\bf 16}$ ($+1$), ${\bf 10}$ ($2$) and ${\bf 1}$ ($+4$) representations. The ${\bf 16}$plets contain Standard Model (SM) fermions plus righthanded neutrinos, and the ${\bf 10}$plet and the singlet fermions are introduced to make the model anomalyfree. Gauge coupling unification at $M_{GUT} \simeq 5 \times 10^{15}10^{16}$ GeV is achieved by including an intermediate PatiSalam breaking at $M_{I} \simeq 10^{12}10^{11}$ GeV, which is a natural scale for the seesaw mechanism. For $M_{I} \simeq 10^{12}10^{11}$, proton decay will be tested by the HyperKamiokande experiment. The extra fermions acquire their masses from $U(1)_\psi$ symmetry breaking, and a $U(1)_\psi$ Higgs field drives a successful inflectionpoint inflation with a low Hubble parameter during inflation, $H_{inf} \ll M_{I}$. Hence, cosmologically dangerous monopoles produced from $SO(10)$ and PS breakings are diluted away. The reheating temperature after inflation can be high enough for successful leptogenesis. With the Higgs field contents of our model, a ${\bf Z}_2$ symmetry remains unbroken after GUT symmetry breaking, and the lightest mass eigenstate among linear combinations of the ${\bf 10}$plet and the singlet fermions serves as a Higgsportal dark matter (DM). We identify the parameter regions to reproduce the observed DM relic density while satisfying the current constraint from the direct DM detection experiments. The present allowed region will be fully covered by the future direct detection experiments such as LUXZEPLIN DM experiment. In the presence of the extra fermions, the SM Higgs potential is stabilized up to $M_{I}$.

Presupernova neutrino signals as potential probes of neutrino mass hierarchy
arXiv:1906.06839
by: Guo, Gang (Darmstadt, GSI) et al.
Abstract: We assess the potential of using presupernova neutrino signals at the Jiangmen Underground Neutrino Observatory (JUNO) to probe the yetunknown neutrino mass hierarchy. Using models for stars of 12, 15, 20, and 25 solar masses, we find that if the electron antineutrino signals from such a star can be predicted precisely and the star is within ~440880 pc, the number of events of electron antineutrino captures on protons detected within one day of its explosion allows to determine the hierarchy at the > ~95% confidence level. For determination at this level using such signals from Betelgeuse, which is at a distance of ~222 pc, the uncertainty in the predicted number of signals needs to be < ~1430%. In view of more realistic uncertainties, we discuss and advocate a modelindependent determination using both electron neutrino and antineutrino signals from Betelgeuse. This method is feasible if the cosmogenic background for neutrinoelectron scattering events can be reduced by a factor of ~2.510 from the current estimate. Such reduction might be achieved by using coincidence of the background events, the exploration of which for JUNO is highly desirable.

Thermalisation of sterile neutrinos in the early Universe in the 3+1 scheme with full mixing matrix
arXiv:1905.11290 JCAP 1907 (2019) 014
by: Gariazzo, S. (U. Valencia (main)) et al.
Abstract: In the framework of a 3+1 scheme with an additional inert state, we consider the thermalisation of sterile neutrinos in the early Universe taking into account the full $4\times4$ mixing matrix. The evolution of the neutrino energy distributions is found solving the momentumdependent kinetic equations with full diagonal collision terms, as in previous analyses of flavour neutrino decoupling in the standard case. The degree of thermalisation of the sterile state is shown in terms of the effective number of neutrinos, $N_{\rm eff}$, and its dependence on the three additional mixing angles ($\theta_{14}$, $\theta_{24}$, $\theta_{34}$) and on the squared mass difference $\Delta m^2_{41}$ is discussed. Our results are relevant for fixing the contribution of a fourth light neutrino species to the cosmological energy density, whose value is very well constrained by the final Planck analysis. For the preferred region of activesterile mixing parameters from shortbaseline neutrino experiments, we find that the fourth state is fully thermalised ($N_{\rm eff}\simeq 4$).

BEST potential in testing the eVscale sterile neutrino explanation of reactor antineutrino anomalies
arXiv:1905.07437 INRTH/2019010 Phys.Rev. D99 (2019) 111702
by: Barinov, Vladislav (Moscow, INR) et al.
Abstract: Baksan Experiment on Sterile Neutrino (BEST) is presently at the stage of production of the artificial neutrino source Cr51, the gallium exposure will start in July and proceed for three months. While aiming specifically at investigating the Gallium neutrino anomaly (SAGE and GALLEX experiments), BEST can do more and it is tempting to estimate its ability in testing sterile neutrino explanation of antineutrino (reactor) anomalies. We observe a moderate sensitivity to the region in model parameter space (sterile neutrino mass and mixing with active electron neutrino) outlined by the old reactor antineutrino anomaly and the best fit of DANSS experiment, while the Neutrino4 favorite region falls right in the BEST ballpark. In particular, by analyzing SAGE+GALLEX and Neutrino4 $\chi^2$ distributions we find that Neutrino4 results are fully consistent with the Gallium anomaly, the significance of the combined anomaly almost reaches 4$\sigma$ level. If the BEST confirms the Neutrino4 results, the joint analysis will indicate more than 5$\sigma$ evidence for the sterile neutrino of eVscale mass.

Measuring Higgs selfcouplings in the presence of VVH and VVHH at the ILC
arXiv:1905.06601 Int.J.Mod.Phys. A34 (2019) 1950094
by: Kumar, Satendra (Indian Inst. Tech., Guwahati) et al.
Abstract: The recent discovery of a Higgs boson at the LHC, while establishing the Higgs mechanism as the way of electroweak symmetry breaking, started an era of precision measurements involving the Higgs boson. In an effective Lagrangian framework, we consider the $e^+e^\rightarrow ZHH$ process at the ILC running at a centre of mass energy of 500 GeV to investigate the effect of the $ZZH$ and $ZZHH$ couplings on the sensitivity of $HHH$ coupling in this process. Our results show that the sensitivity of the trilinear Higgs self couplings on this process has somewhat strong dependence on the Higgsgauge boson couplings. Single and two parameter reach of the ILC with an integrated luminosity of 1000 fb$^{1}$ are obtained on all the effective couplings indicating how these limits are affected by the presence of anomalous $ZZH$ and $ZZHH$ couplings. The kinematic distributions studied to understand the effect of the anomalous couplings, again, show a strong influence of $Z$$H$ couplings on the dependence of these distributions on $HHH$ coupling. Similar results are indicated in the case of the process, $e^+e^\rightarrow \nu\bar \nu HH$, considered at a centre of mass energy of 2 TeV, where the cross section is large enough. The effect of $WWH$ and $WWHH$ couplings on the sensitivity of $HHH$ coupling is clearly established through our analyses in this process.

Sensitivity bounds on heavy neutrino mixing $U_{\mu N}^2$ and $U_{\tau N}^2$ from LHCb upgrade
arXiv:1904.12858 USMTH361 Phys.Rev. D100 (2019) 015014
by: Cvetic, Gorazd (CCTVal, Valparaiso) et al.
Abstract: Decays of heavy pseudoscalar mesons $B$, $B_c$, $B_s$ and $D_s$ at LHCb upgrade are considered, which produce either two equal sign muons or taus. In addition, we consider the analogous decays with opposite sign muons or taus. All these decays are considered to be mediated by a heavy onshell neutrino $N$. Such decays of $B$ mesons, if not detected, will give in general stringent upper bounds on the heavylight mixing parameter $U_{\mu N}^2$ as a function of the neutrino mass $M_N \sim 1$ GeV, principally due to the large expected number of produced mesons $B$. While some of the decays of the other mentioned mesons are attractive due to a weaker CKMsuppression, the expected produced number of such mesons is significantly smaller that that of $B$'s; therefore, the sensitivity bounds from such decays are in general comparable or less restrictive. When $\tau$ pairs are produced, only two types of such decays are significant: $B, B_{c} \to \tau \tau \pi$, giving us stringent upper bounds on $U_{\tau N}^2$; the other decays with a pair of $\tau$, such as $B \to D^{(*)} \tau \tau \pi$, are prohibited or very suppressed by kinematics.

FIMP dark matter candidate(s) in a $B − L$ model with inverse seesaw mechanism
arXiv:1904.10015 JHEP 1906 (2019) 095
by: Abdallah, Waleed (HarishChandra Res. Inst.) et al.
Abstract: The nonthermal dark matter (DM) production via the socalled freezein mechanism provides a simple alternative to the standard thermal WIMP scenario. In this work, we consider a popular U(1)$_{B−}_{L}$ extension of the standard model (SM) in the context of inverse seesaw mechanism which has at least one (fermionic) FIMP DM candidate. Due to the added ℤ$_{2}$ symmetry, a SM gauge singlet fermion, with mass of order keV, is stable and can be a warm DM candidate. Also, the same ℤ$_{2}$ symmetry helps the lightest righthanded neutrino, with mass of order GeV, to be a stable or longlived particle by making a corresponding Yukawa coupling very small. This provides a possibility of a two component DM scenario as well. Firstly, in the absence of a GeV DM component (i.e., without tuning its corresponding Yukawa coupling to be very small), we consider only a keV DM as a single component DM, which is produced by the freezein mechanism via the decay of the extra Z$^{′}$ gauge boson associated to U(1)$_{B−}_{L}$ and can consistently explain the DM relic density measurements. In contrast with most of the existing literature, we have found a reasonable DM production from the annihilation processes. After numerically studying the DM production, we show the dependence of the DM relic density as a function of its relevant free parameters. We use these results to obtain the parameter space regions that are compatible with the DM relic density bound. Secondly, we study a two component DM scenario and emphasize that the current DM relic density bound can be satisfied for a wide range of parameter space.

Bmeson charged current anomalies: the postMoriond status
arXiv:1904.10432 Phys.Rev. D100 (2019) 011701
by: Bardhan, Debjyoti (Ben Gurion U. of Negev) et al.
Abstract: In this note, we discuss the impact of the recent Belle result on the various theoretical explanations of the $R_D$ and $R_{D^*}$ anomalies. The pure tensor explanation, which was strongly disfavoured by the measurements of $F_L^{D^*}$ and high$p_T$ $p \, p \to \tau \, \nu$ searches before Moriond, is now completely allowed because of reduction of the experimental worldaverage. Moreover, the pure rightchiral vector solution (involving rightchiral neutrinos) has now moved into the $2\sigma$ allowed range of the LHC $p \, p \to \tau \, \nu$ searches. We also critically reexamine the bound on $\mathcal{B}(B_c^ \to \tau^ \bar{\nu}_\tau)$ from LEP data and show that the bound is considerably weaker than the number $10\%$ often used in the recent literature.

Exotic colored fermions and lepton number violation at the LHC
arXiv:1904.07257 Phys.Rev. D99 (2019) 115028
by: Carquin, E. (Santa Maria U., Valparaiso) et al.
Abstract: Majorana neutrino mass models with a scale of lepton number violation of order teraelectronvolts potentially lead to signals at the LHC. Here, we consider an extension of the standard model with a colored octet fermion and a scalar leptoquark. This model generates neutrino masses at twoloop order. We make a detailed Monte Carlo study of the lepton number violating signal at the LHC in this model, including a simulation of standard model backgrounds. Our forecast predicts that the LHC with 300/fb should be able to probe this model up to coloroctet fermion masses in the range of (2.6–2.7) TeV, depending on the lepton flavor of the final state.

Physics with Beam TauNeutrino Appearance at DUNE
arXiv:1904.07265 FERMILABPUB19146T NUHEPTH/1904 Phys.Rev. D100 (2019) 016004
by: De Gouvêa, André (Northwestern U.) et al.
Abstract: We explore the capabilities of the upcoming Deep Underground Neutrino Experiment (DUNE) to measure $\nu_\tau$ chargedcurrent interactions and the associated oscillation probability $P(\nu_\mu \to \nu_\tau)$ at its far detector, concentrating on how such results can be used to probe neutrino properties and interactions. DUNE has the potential to identify significantly more $\nu_\tau$ events than all existing experiments and can use this data sample to nontrivially test the threemassiveneutrinos paradigm by providing complementary measurements to those from the $\nu_e$ appearance and $\nu_\mu$ disappearance channels. We further discuss the sensitivity of the $\nu_\tau$ appearance channel to several hypotheses for the physics that may lurk beyond the threemassiveneutrinos paradigm: a nonunitary lepton mixing matrix, the $3+1$ light neutrinos hypothesis, and the existence of nonstandard neutralcurrent neutrino interactions. Throughout, we also consider the relative benefits of the proposed highenergy tune of the LongBaseline Neutrino Facility (LBNF) beamline.

Permanent mean spin source of the chiral magnetic effect in neutron stars
arXiv:1904.05768 JCAP 1906 (2019) 053
by: Dvornikov, Maxim (IZMIRAN) et al.
Abstract: We suggest the generalization of the Anomalous MagnetoHydroDynamics (AMHD) in the chiral plasma of a neutron star (NS) accounting for the mean spin in the ultrarelativistic degenerate electron gas within the magnetized NS core as a continuing source of the chiral magnetic effect. Using the mean field dynamo model generalized in AMHD, one can obtain the growth of a seed magnetic field up to $10^{18}\,\text{G}$ for an old nonsuperfluid NS at its neutrino cooling era $t < 10^6\,\text{yr}$, while neglecting any matter turbulence within its core and assuming the rigid NS rotation. The application of the suggested approach to the evolution of magnetic fields observed in magnetars, $B\sim 10^{15}\,\text{G}$, should be selfconsistent with all approximations used in the suggested laminar dynamo, at least, up to the jumps of growing fields.

Shortbaseline neutrino oscillations with 3 + 1 nonunitary mixing
arXiv:1904.02093 Phys.Lett. B795 (2019) 236240
by: Giunti, C. (INFN, Turin)
Abstract: We consider a scenario with unitary mixing of the three light standard neutrinos and a nonunitary mixing contribution of a heavier massive neutrino that can generate shortbaseline neutrino oscillations. We show that this scenario predicts constant flavorchanging probabilities at shortbaseline distances. Therefore, it cannot explain the spectral distortions observed in the LSND and MiniBooNE appearance experiments. On the other hand, the survival probabilities oscillate as functions of $L/E$ and could explain oscillations in shortbaseline disappearance experiments. We also derive the bounds on the mixing parameters from the existing shortbaseline neutrino oscillation data.

$b\to s\ell^+\ell^$ transitions in twoHiggsdoublet models
arXiv:1903.10440 PSIPR1902 ZUTH 10/19 JHEP 1906 (2019) 119
by: Crivellin, Andreas (PSI, Villigen) et al.
Abstract: In this article we study $b\to s\mu^+\mu^$ transitions and possible correlations with the anomalous magnetic moment of the muon ($a_\mu$) within twoHiggsdoublet models with generic Yukawa couplings, including the possibility of righthanded neutrinos. We perform the matching on the relevant effective Hamiltonian and calculate the leading oneloop effects for $b\to s\ell\ell^{(\prime)}$, $b\to s\gamma$, $\Delta B=\Delta S=2$, $b\to s\nu\bar\nu$ and $\ell\to\ell^\prime\gamma$ transitions in a general $R_\xi$ gauge. Concerning the phenomenology, we find that an explanation of the hints for new physics in $b\to s\mu^+\mu^$ data is possible once righthanded neutrinos are included. If lepton flavour violating couplings are allowed, one can account for the discrepancy in $a_\mu$ as well. However, only a small portion of parameter space gives a good fit to $b\to s\mu^+\mu^$ data and the current bound on $h\to\tau\mu$ requires the mixing between the neutral Higgses to be very small if one aims at an explanation of $a_\mu$.

Stability, reheating and leptogenesis
arXiv:1903.08658 SCIPP 18/07 JHEP 1906 (2019) 098
by: Croon, Djuna (TRIUMF) et al.
Abstract: In a minimal model of leptogenesis, the observed baryon asymmetry is realized after highscale reheating into the lightest sterile neutrino. We consider constraints on this scenario from the stability of the Higgs vacuum during preheating. Depending on the reheat temperature, the lightest sterile neutrino may be in or out of thermal equilibrium at production. Demanding stability of the Higgs vacuum during preheating, we find strong constraints favoring the nonthermal leptogenesis scenario.

Fits to NonSupersymmetric SO(10) Models with Type I and II Seesaw Mechanisms Using Renormalization Group Evolution
arXiv:1903.08241 JHEP 1906 (2019) 085
by: Ohlsson, Tommy (Royal Inst. Tech., Stockholm) et al.
Abstract: We consider numerical fits to nonsupersymmetric $\mathrm{SO}(10)$based models in which neutrino mass is generated by the typeI or typeII seesaw mechanism or a combination of both. The fits are performed with a sophisticated topdown procedure, taking into account the renormalization group equations of the gauge and Yukawa couplings, integrating out relevant degrees of freedom at their corresponding mass scales, and using recent data for the Standard Model observables. We find acceptable fits for normal neutrino mass ordering only and with neutrino mass generated by either typeI seesaw only or a combination of types I and II seesaw in which typeI seesaw is dominant. Furthermore, we find predictions from the best fit regarding the small neutrino masses, the effective neutrinoless double beta decay mass, and the leptonic CPviolating phase. Finally, we show that the fits are rather insensitive to the chosen value of the unification scale.

Deviations to TriBiMaximal mixing in the limit of $\mu − \tau$ symmetry
arXiv:1903.05597 Phys.Lett. B794 (2019) 8995
by: RiveraAgudelo, Diana C. (Santiago de Cali U.) et al.
Abstract: In the limit of an approximate $\mu\tau$ symmetry in the neutrino mass matrix, we explore deviations to the TriBiMaximal mixing pattern in the neutrino sector. We consider two different ansatzes for the corrected pattern to predict the current values of neutrino mixing parameters. We show that it is possible to constrain the Majorana $CP$ phases by studying their correlation to the mixing parameters and we study their effects on neutrinoless double beta decay observables. These predictions are sharp for the quasidegenerate ordering and can be tested in upcoming experiments.

Neutrino Topology Reconstruction at DUNE and Applications to Searches for Dark Matter Annihilation in the Sun
arXiv:1903.04175 UH511130018 JCAP 1907 (2019) 006
by: Rott, Carsten (Sungkyunkwan U.) et al.
Abstract: We consider a new technique for neutrino energy and topology reconstruction at DUNE. In particular, we show that when the direction of the incoming neutrino is known, one can use the measured directions of the outgoing leptonic and hadronic particles to reconstruct poorlymeasured quantities, such as the hadronic cascade energy. We show that this alternative technique yields an energy resolution which is comparable to current reconstruction methods which sum measured energies. As a proof of concept we apply this new reconstruction method to a search for dark matter annihilation in the Sun. We show that the use of directional information from both the leptonic and hadronic interaction products allows one to effectively reject backgrounds and isolate the signal, giving competitive sensitivities.

MultiHiggsDoublet Models and Singular Alignment
arXiv:1903.00983 JHEP 1907 (2019) 036
by: Rodejohann, Werner (Heidelberg, Max Planck Inst.) et al.
Abstract: We consider a 4Higgsdoublet model in which each Higgs doublet gives mass to one of the fermion sets $\{ m_t\}$, $\{ m_b,m_\tau,m_c \}$, $\{ m_\mu,m_s \}$, and $\{ m_d,m_u,m_e \}$. The sets have the feature that within each of them the masses are similar. Our model explains the mass hierarchies of the sets by hierarchies of the vacuum expectation values of the Higgs doublets associated to them. All Yukawa couplings are therefore of order one. Neutrino masses are generated by a typeI seesaw mechanism with PeVscale singlet neutrinos. To avoid the appearance of treelevel flavor changing neutral currents, we assume that all Yukawa matrices are singularly aligned in flavor space. We mean by this that the Yukawa matrices are given as linear combinations of the rank $1$ matrices that appear in the singular value decomposition of the mass matrix. In general, singular alignment allows to avoid flavor changing neutral currents in models with multiple Higgs doublets.

Neutrino Portals to Dark Matter
arXiv:1903.00006 FTUAM195 IFTUAM/CSIC1919 IPPP/19/17 Eur.Phys.J. C79 (2019) 555
by: Blennow, M. (Madrid, IFT) et al.
Abstract: We explore the possibility that dark matter interactions with Standard Model particles are dominated by interactions with neutrinos. We examine whether it is possible to construct such a scenario in a gauge invariant manner. We first study the coupling of dark matter to the full lepton doublet and confirm that this generally leads to the dark matter phenomenology being dominated by interactions with charged leptons. We then explore two different implementations of the neutrino portal in which neutrinos mix with a Standard Model singlet fermion that interacts directly with dark matter through either a scalar or vector mediator. In the latter cases we find that the neutrino interactions can dominate the dark matter phenomenology. Present neutrino detectors can probe dark matter annihilations into neutrinos and already set the strongest constraints on these realisations. Future experiments such as HyperKamiokande, MEMPHYS, DUNE, or DARWIN could allow to probe dark matterneutrino cross sections down to the value required to obtain the correct thermal relic abundance.

Neutrino Quantum Kinetics in Compact Objects
arXiv:1903.00022 Phys.Rev. D99 (2019) 123014
by: Richers, Sherwood A. (North Carolina State U.) et al.
Abstract: Neutrinos play a critical role of transporting energy and changing the lepton density within corecollapse supernovae and neutron star mergers. The quantum kinetic equations (QKEs) combine the effects of neutrinomatter interactions treated in classical Boltzmann transport with the neutrino flavorchanging effects treated in neutrino oscillation calculations. We present a method for extending existing neutrino interaction rates to full QKE source terms for use in numerical calculations. We demonstrate the effects of absorption and emission by nucleons and nuclei, electron scattering, electronpositron pair annihilation, nucleonnucleon bremsstrahlung, neutrinoneutrino scattering. For the first time, we include all these collision terms selfconsistently in a simulation of the full isotropic QKEs in conditions relevant to corecollapse supernovae and neutron star mergers. For our choice of parameters, the longterm evolution of the neutrino distribution function proceeds similarly with and without the oscillation term, though with measurable differences. We demonstrate that electron scattering, nucleonnucleon bremsstrahlung processes, and fourneutrino processes dominate flavor decoherence in the protoneutron star (PNS), absorption dominates near the shock, and all of the considered processes except elastic nucleon scattering and neutrinoneutrino processes are relevant in the decoupling region. Finally, we propose an effective decoherence opacity that at most energies predicts decoherence rates to within a factor of 10 in our model PNS and within 20% outside of the PNS.

Neutrino spin oscillations in external fields in curved spacetime
arXiv:1902.11285 Phys.Rev. D99 (2019) 116021
by: Dvornikov, Maxim (Troitsk, IZMIRAN)
Abstract: We study spin oscillations of massive Dirac neutrinos in background matter, electromagnetic and gravitational fields. First, using the Dirac equation for a neutrino interacting with the external fields in curved spacetime, we rederive the quasiclassical equation for the neutrino spin evolution, which was proposed previously basing on principles of the general covariance. Then, we apply this result for the description of neutrino spin oscillations in nonmoving and unpolarized matter under the influence of a constant transverse magnetic field and a gravitational wave. We derive the effective Schr\"odinger equation for neutrino oscillations in these external fields and solve it numerically. Choosing realistic parameters of external fields, we show that the parametric resonance can take place in spin oscillations of low energy neutrinos. Some astrophysical applications are briefly discussed.

A Precise Determination of (Anti)neutrino Fluxes with (Anti)neutrinoHydrogen Interactions
arXiv:1902.09480 Phys.Lett. B795 (2019) 424431
by: Duyang, H. (South Carolina U.) et al.
Abstract: We present a novel method to accurately determine the flux of neutrinos and antineutrinos, one of the dominant systematic uncertainty affecting current and future longbaseline neutrino experiments, as well as precision neutrino scattering experiment. Using exclusive topologies in $\nu(\bar \nu)$hydrogen interactions, $\nu_\mu p \to \mu^ p \pi^+$, $\bar \nu_\mu p \to \mu^+ p \pi^$, and $\bar \nu_\mu p \to \mu^+ n$ with small hadronic energy, we achieve an overall accuracy on the relative fluxes better than 1\% in the energy range covering most of the available flux. Since we cannot rely on simulations nor model corrections at this level of precision, we present techniques to constrain all relevant systematic uncertainties using data themselves. The method can be implemented using the approach we recently proposed to collect high statistics samples of $\nu(\bar \nu)$hydrogen interactions in a lowdensity and highresolution detector, which could serve as part of the near detector complex in a longbaseline neutrino experiment, as well as a dedicated beam monitoring detector.

Impact of form factor uncertainties on interpretations of coherent elastic neutrinonucleus scattering data
arXiv:1902.07398 JHEP 1906 (2019) 141
by: Aristizabal Sierra, D. (Santa Maria U., Valparaiso) et al.
Abstract: The standard model coherent elastic neutrinonucleus scattering (CE$\nu$NS) cross section is subject to nuclear form factor uncertainties, mainly driven by the rootmeansquare radius of the neutron density distribution. Motivated by COHERENT phases IIII and future multiton direct detection dark matter searches, we evaluate these uncertainties in cesium iodide, germanium, xenon and argon detectors. We find that the uncertainties become relevant for momentum transfers $q\gtrsim 20$ MeV and are essentially independent of the form factor parameterization. Consequently, form factor uncertainties are not important for CE$\nu$NS induced by reactor or solar neutrinos. Taking into account these uncertainties, we then evaluate their impact on measurements of CE$\nu$NS at COHERENT, the diffuse supernova background (DSNB) neutrinos and subGeV atmospheric neutrinos. We also calculate the relative uncertainties in the number of COHERENT events for different nuclei as a function of recoil energy. For DSNB and atmospheric neutrinos, event rates at a liquid argon detector can be uncertain to more than 5%. Finally, we consider the impact of form factor uncertainties on searches for nonstandard neutrino interactions, sterile neutrinos and neutrino generalized interactions. We point out that studies of new physics using CE$\nu$NS data are affected by neutron form factor uncertainties, which if not properly taken into account may lead to the misidentification of new physics signals. The uncertainties quantified here are also relevant for dark matter direct detection searches.

Predictive Scotogenic Model with Flavor Dependent Symmetry
arXiv:1901.07798 Eur.Phys.J. C79 (2019) 522
by: Han, ZhiLong (Jinan U.) et al.
Abstract: In this paper, we propose a viable approach to realise two texturezeros in the scotogenic model with flavor dependent $U(1)_{B2L_\alphaL_\beta}$ gauge symmetry. These models are extended by two righthanded singlets $N_{Ri}$ and two inert scalar doublets $\eta_{i}$, which are odd under the dark $Z_2$ symmetry. Among all the six constructed textures, texture $A_1$ and $A_2$ are the only two allowed by current experimental limits. Then choosing texture $A_1$ derived from $U(1)_{B2L_eL_\tau}$, we perform a detail analysis on the corresponding phenomenology such as predictions of neutrino mixing parameters, lepton flavor violation, dark matter and collider signatures. One distinct nature of such model is that the structure of Yukawa coupling $\bar{L}\tilde{\eta}N_R$ is fixed by neutrino oscillation data, and can be further tested by measuring the branching ratios of charged scalars $\eta_{1,2}^\pm$.

A Two Higgs Doublet Model for Dark Matter and Neutrino Masses
arXiv:1901.05476 IIPDM2019 Phys.Lett. B795 (2019) 319326
by: Camargo, Daniel A. (IIP, Brazil) et al.
Abstract: Motivated by the interesting features of Two Higgs Doublet Models (2HDM) we present a 2HDM extension where the stability of dark matter, neutrino masses and the absence of flavor changing interactions are explained by promoting baryon and lepton number to gauge symmetries. Neutrino masses are addressed within the usual type I seesaw mechanism. A vectorlike fermion acts as dark matter and it interacts with Standard Model particles via the kinetic and mass mixings between the neutral gauge bosons. We compute the relevant observables such as the dark matter relic density and spinindependent scattering cross section to outline the region of parameter space that obeys current and projected limits from collider and direct detection experiments via thermal and nonthermal dark matter production.

Neutralcurrent weak pion production off the nucleon in covariant chiral perturbation theory
arXiv:1901.00773 Phys.Lett. B794 (2019) 109113
by: Yao, DeLiang (Lanzhou, Inst. Modern Phys.) et al.
Abstract: Neutral current single pion production induced by neutrinos and antineutrinos on nucleon targets has been investigated in manifestly relativistic baryon chiral perturbation theory with explicit $\Delta(1232)$ degrees of freedom up to $\mathcal{O}(p^3)$. At low energies, where chiral perturbation theory is applicable, the total cross sections for the different reaction channels exhibit a sizable nonresonant contribution, which is not present in event generators of broad use in neutrino oscillation and cross section experiments such as GENIE and NuWro.

Finite modular subgroups for fermion mass matrices and baryon/lepton number violation
arXiv:1812.11072 EPHOU18017 HUPD1810 Phys.Lett. B794 (2019) 114121
by: Kobayashi, Tatsuo (Hokkaido U.) et al.
Abstract: We study a flavor model that the quark sector has the S3 modular symmetry while the lepton sector has the A4 modular symmetry. Our model leads to characteristic quark mass matrices which are consistent with experimental data of quark masses, mixing angles and the CP violating phase. The lepton sector is also consistent with the experimental data of neutrino oscillations. We also study baryon and lepton number violations in our flavor model.

Correlations and degeneracies among the NSI parameters with tunable beams at DUNE
arXiv:1812.10290 Phys.Rev. D99 (2019) 115032
by: Masud, Mehedi (Valencia U., IFIC) et al.
Abstract: The Deep Underground Neutrino Experiment (DUNE) is a leading experiment in neutrino physics which is presently under construction. DUNE aims to measure the yet unknown parameters in the three flavour oscillation scenario which includes discovery of leptonic CP violation, determination of the mass hierarchy and determination of the octant of $\theta_{23}$. Additionally, the ancillary goals of DUNE include probing the subdominant effects induced by new physics. A widely studied new physics scenario is that of nonstandard neutrino interactions (NSI) in propagation which impacts the oscillations of neutrinos. We consider some of the essential NSI parameters impacting the oscillation signals at DUNE and explore the space of NSI parameters as well as study their correlations among themselves and with the yet unknown CP violating phase, $\delta$ appearing in the standard paradigm. The experiment utilizes a wide band beam and provides us with a unique opportunity to utilize different beam tunes at DUNE. We demonstrate that combining information from different beam tunes (low energy, LE and medium energy, ME) available at DUNE impacts the ability to probe some of these parameters and leads to altering the allowed regions in twodimensional space of parameters considered.

Measuring the atmospheric neutrino oscillation parameters and constraining the 3+1 neutrino model with ten years of ANTARES data
arXiv:1812.08650 JHEP 1906 (2019) 113
by: Albert, A. (Strasbourg, IPHC) et al.
Abstract: The ANTARES neutrino telescope has an energy threshold of a few tens of GeV. This allows to study the phenomenon of atmospheric muon neutrino disappearance due to neutrino oscillations. In a similar way, constraints on the 3+1 neutrino model, which foresees the existence of one sterile neutrino, can be inferred. Using data collected by the ANTARES neutrino telescope from 2007 to 2016, a new measurement of $\Delta m^2_{32}$ and $\theta_{23}$ has been performed  which is consistent with world bestfit values  and constraints on the 3+1 neutrino model have been derived.

Evolution of dark matter velocity dispersion
arXiv:1812.06891 JCAP 1906 (2019) 039
by: Erschfeld, Alaric (U. Heidelberg, ITP) et al.
Abstract: Cosmological perturbation theory for the late Universe dominated by dark matter is extended beyond the perfect pressureless fluid approximation by taking the dark matter velocity dispersion tensor as an additional field into account. A proper tensor decomposition of the latter leads to two additional scalar fields, as well as a vector and a tensor field. Most importantly, the trace of the velocity dispersion tensor can have a spatially homogeneous expectation value. While it decays at early times, we show that a backreaction effect quadratic in perturbations makes it grow strongly at late times. We compare sterile neutrinos as a candidate for comparatively warm dark matter to weakly interacting massive particles as a rather cold dark matter candidate and show that the late time growth of velocity dispersion is stronger for the latter. Another feature of a nonvanishing velocity dispersion tensor is that it can account for multiple streams within the fluid description and thereby allows to treat times and scales beyond shellcrossing.

Heavy Majorana Neutrino Production at Future $ep$ Colliders
arXiv:1811.10313 Phys.Lett. B795 (2019) 4955
by: Li, ShiYuan (Shandong U.) et al.
Abstract: The heavy singlet Majorana neutrinos are introduced to generate the neutrino mass in the socalled phenomenological typeI seesaw mechanism. The phenomena induced by the heavy Majorana neutrinos are important to search for new physics. In this paper, we explore the heavy Majorana neutrino production and decay at future e−p colliders. The corresponding cross sections via W and photon fusion are predicted for different collider energies. Combined with the results of the heavy Majorana neutrino production via single W exchange, this work can provide helpful information to search for heavy Majorana neutrinos at future e−p colliders.

Angular distribution as an effective probe of new physics in semihadronic threebody meson decays
arXiv:1811.08190 LDU18004 Phys.Rev. D100 (2019) 015005
by: Kim, C.S. (IPAP, Seoul) et al.
Abstract: We analyze, in a fully modelindependent manner, the effects of new physics on a few semihadronic threebody meson decays of the type $P_i \to P_f f_1 f_2$, where $P_i$, $P_f$ are well chosen pseudoscalar mesons and $f_{1,2}$ denote fermions out of which at least one gets detected in experiments. We find that the angular distribution of events of these decays can probe many interesting new physics, such as the nature of the intermediate particle that can cause leptonflavor violation, or presence of heavy sterile neutrino, or new intermediate particles, or new interactions. We also provide angular asymmetries which can quantify the effects of new physics in these decays. We illustrate the effectiveness of our proposed methodology with a few well chosen decay modes showing effects of certain new physics possibilities without any hadronic uncertainties.

Fat Jet Signature of a Heavy Neutrino at Lepton Collider
arXiv:1810.08970 Phys.Rev. D100 (2019) 015012
by: Chakraborty, Sabyasachi (Florida State U.) et al.
Abstract: We explore the discovery prospect of a very heavy neutrino at the proposed $e^+e^$ collider for two different c.m.energies $\sqrt{s}=1.4$ TeV and 3 TeV. We consider production of heavy neutrino via $s$ and $t$channel processes, and its subsequent prompt decays leading to semileptonic final states, along with significant missing energy. For our choice of masses, the gauge boson produced from heavy neutrino decay is highly boosted, leading to a fatjet. We carry out a detail signal and background analysis for $e^{\pm}+j_{\rm{fat}}+\cancel{E}_{T}$ final state using both cut based and multivariate techniques. We show that a heavy neutrino of mass $6002700$ GeV and activesterile mixing $V_{eN}^2 \sim 10^{5}$ can be probed with $5\sigma$ significance at $e^{+}e^{}$ collider after collecting $\mathcal{L}=500$ $\rm{fb}^{1}$ of data. We find the sensitivity reach at $e^{+}e^{}$ collider is order of magnitude enhanced as compared to LHC.

Asymptotic safety and Conformal Standard Model
arXiv:1810.08461 Phys.Rev. D99 (2019) 115029
by: Grabowski, Frederic (Warsaw U.) et al.
Abstract: We show that the conformal standard model supplemented with asymptotically safe gravity can be valid up to arbitrarily high energies and give a complete description of particle physics phenomena. We restrict the mass of the second scalar particle to ∼300 GeV and the masses of heavy neutrinos to ∼340 GeV. These predictions can be explicitly tested in the nearby future.

From $D_{s}^{\pm}$ production asymmetry at the LHC to prompt $\nu_{\tau}$ at IceCube
arXiv:1809.05424 Phys.Lett. B794 (2019) 2935
by: Goncalves, Victor P. (Pelotas U.) et al.
Abstract: The description of the heavy meson production at large energies and forward rapidities at the LHC is fundamental to derive realistic predictions of the prompt atmospheric neutrino flux at the IceCube Observatory. In particular, the prompt tau neutrino flux is determined by the decay of Ds mesons produced in cosmic ray–air interactions at high energies and large values of the Feynman xF variable. Recent data of the LHCb Collaboration indicate a production asymmetry for Ds+ and Ds− mesons, which cannot be explained in terms of the standard modeling of the hadronization process. In this paper we demonstrate that this asymmetry can be described assuming an asymmetric strange sea ( s(x)≠s¯(x) ) in the proton wave function and taking into account the dominant charm and subdominant strange fragmentation into Ds mesons. Moreover, we show that the strange quark fragmentation contribution is dominant at large xF (≥0.3). The prompt ντ flux is calculated and the enhancement associated with the strange quark fragmentation contribution, disregarded in previous calculations, is estimated. The considered scenario leads to quite sizable enhancement of the highenergy τ neutrino flux.

Constraining light sterile neutrino mass with the BICEP2/Keck Array 2014 Bmode polarization data
arXiv:1807.10294 Eur.Phys.J. C79 (2019) 557
by: Roy Choudhury, Shouvik (HarishChandra Res. Inst.) et al.
Abstract: We explore the thermal light sterile neutrino situation from cosmological perspective in the $\Lambda \text {CDM} + r_{0.05} + N_{\text {eff}} + m^{\text {eff}}_{\text {s}}$ model using combinations of latest data sets available. Among CMB datasets, we use Planck 2015 temperature and lowl polarization data and the latest data release on the Bmode polarization from the BICEP2/Keck collaboration (BK14). We also use the latest Baryon Acoustic Oscillations (BAO) data from SDSSIII BOSS DR12, MGS, and 6dFS, and a Gaussian prior (HST) on the Hubble constant ( $H_0 = 73.24 \pm 1.74$ km/s/Mpc) from direct measurements by Hubble Space Telescope. We find that inclusion of BK14 data makes the constraints on the effective mass of sterile neutrino ( $m^{\text {eff}}_{\text {s}}$ ) slightly stronger by preferring higher $\sigma _8$ values. The bound of $m^{\text {eff}}_{\text {s}}<$ 0.46 eV (95% C.L.) is found for the combination of Planck 2015, BAO and BK14 datasets, whereas the bound is $m^{\text {eff}}_{\text {s}}<$ 0.53 eV (95% C.L.) without the BK14 data. Our most aggressive bound of $m^{\text {eff}}_{\text {s}}<$ 0.28 eV (95% C.L.) is obtained with Planck 2015, HST and BK14. Our analysis indicates that fully thermalized sterile neutrinos with mass $\sim 1$ eV are slightly more disfavoured with the inclusion of BK14 data. It also seems to make the agreement between Planck 2015 and CFHTLenS (weak gravitational lensing data) worse due to the higher $\sigma _8$ values.

Bayesian analysis of sneutrino dark matter in the NMSSM with a typeI seesaw mechanism
arXiv:1807.03762 Phys.Rev. D99 (2019) 115033
by: Cao, Junjie (Henan Normal U.) et al.
Abstract: In the NexttoMinimal Supersymmetric Standard Model (NMSSM) with extra heavy neutrino superfields, neutrino may acquire its mass via a seesaw mechanism and sneutrino may act as a viable dark matter (DM) candidate. Given the strong tension between the naturalness for $Z$ boson mass and the DM direct detection experiments for customary neutralino DM candidate, we augment the NMSSM with TypeI seesaw mechanism, which is the simplest extension of the theory to predict neutrino mass, and study the scenarios of sneutrino DM. We construct likelihood function with LHC Higgs data, Bphysics measurements, DM relic density and its direct and indirect search limits, and perform a comprehensive scan over the parameter space of the theory by Nested Sampling method. We adopt both Bayesian and frequentist statistical quantities to illustrate the favored parameter space of the scenarios, the DM annihilation mechanism as well as the features of DMnucleon scattering. We find that the scenarios are viable over broad parameter regions, especially the Higgsino mass $\mu$ can be below about $250 {\rm GeV}$ for a significant part of the region, which predicts $Z$ boson mass in a natural way. We also find that the DM usually coannihilated with the Higgsinos to get the measured relic density, and consequently the DMnucleon scattering rate is naturally suppressed to coincide with the recent XENON1T results even for light Higgsinos. Other issues, such as the LHC search for the Higgsinos, are also addressed.

Lowscale leptogenesis and dark matter
arXiv:1807.03309 Eur.Phys.J. C79 (2019) 574
by: Caputo, Andrea (Valencia U., IFIC) et al.
Abstract: An extension of the Standard Model with Majorana singlet fermions in the 1100 GeV range can give rise to a baryon asymmetry at freezein via the CPviolating oscillations of these neutrinos: this is the well known ARS mechanism. In this paper we consider possible extensions of the minimal ARS scenario that can account not only for successful leptogenesis but also explain other open problems such as dark matter. We find that an extension in the form of a weakly coupled BL gauge boson, an invisible QCD axion model, and the singlet majoron model can simultaneously account for dark matter and the baryon asymmetry.

$VHH$ production at the HighLuminosity LHC
Nikhef 2018028 NIKHEF2018028 arXiv:1807.01571 Eur.Phys.J.Plus 134 (2019) 288
by: Nordström, Karl (Nikhef, Amsterdam) et al.
Abstract: We study the phenomenology of associated production of a vector boson with a pair of Higgs bosons ($VHH$) at the HighLuminosity LHC. Despite the low rate of this channel, the scaling of the cross section suggests a measurement could be a useful probe of modifications of the trilinear Higgs boson coupling and anomalous interactions in the gaugeHiggs sector. We focus on both $WHH$ and $ZHH$ production, using the leptonic ($W \to l \nu$, $Z \to ll$, $Z \to \nu \nu$) decay modes of the vector bosons and the $HH \to 4b$ diHiggs decay mode. We show that top pair backgrounds are problematic for the $W \to l \nu$ and $Z \to \nu \nu$ channels, leaving $Z \to ll$ as the most promising decay mode. However, even for this channel, we find limited sensitivity due to a low signal rate. We discuss some potential avenues for improvement.

Azimuthal correlation function of polarized top quark in noncommutative space–time
arXiv:1804.07688 Annals Phys. 406 (2019) 7185
by: Rezaei, Z. (Yazd U.) et al.
Abstract: The azimuthal correlation belongs to a class of polarization observables which vanishes at the Born term level in the standard model for the semileptonic rest frame decay of a polarized top quark t(↑)→bW+→bℓ+υℓ . In this frame, the azimuthal correlation is defined between the planes formed by the vectors (p→ℓ,p→Xb) and (p→ℓ,P→t) . We calculate the azimuthal correlation function of polarized top quark in the framework of the noncommutative standard model for the first time. We find that this observable is nonzero in the leading order of noncommutative space–time. Further the appearance of the oscillatory azimuthal distribution of decay rate provides a practical possibility to test the noncommutativity in particle colliders.

Neutrino oscillation processes with a change of lepton flavor in quantum fieldtheoretical approach
arXiv:1712.04335 J.Exp.Theor.Phys. 128 (2019) 713719
by: Egorov, Vadim O. (SINP, Moscow) et al.
Abstract: The oscillating probabilities of lepton flavor changing neutrino oscillation processes, where neutrinos are detected by chargedcurrent and neutralcurrent interactions, are calculated in a quantum fieldtheoretical approach to neutrino oscillations based on a modification of the Feynman propagator in the momentum reprsentation. The approach is most similar to the standard Feynman diagram technique in the momentum representation. It is found that the oscillating distancedependent probabilities of detecting an electron in experiments with neutrino production in the muonic decay of $\pi^+$meson and the detection of the produced neutrino by chargedcurrent and neutralcurrent interactions exactly coincide with the corresponding probabilities calculated in the standard approach.

SelfDestructing Dark Matter
arXiv:1712.00455 FERMILABPUB17505T NUHEPTH1707 FERMILABPUB17505T NUHEPTH1707 JHEP 1907 (2019) 017
by: Grossman, Yuval (Cornell U., LEPP) et al.
Abstract: We present SelfDestructing Dark Matter (SDDM), a new class of dark matter models which are detectable in large neutrino detectors. In this class of models, a component of dark matter can transition from a longlived state to a shortlived one by scattering off of a nucleus or an electron in the Earth. The shortlived state then decays to Standard Model particles, generating a dark matter signal with a visible energy of order the dark matter mass rather than just its recoil. This leads to striking signals in large detectors with high energy thresholds. We present a few examples of models which exhibit self destruction, all inspired by bound state dynamics in the Standard Model. The models under consideration exhibit a rich phenomenology, possibly featuring events with one, two, or even three lepton pairs, each with a fixed invariant mass and a fixed energy, as well as nontrivial directional distributions. This motivates dedicated searches for dark matter in large underground detectors such as SuperK, Borexino, SNO+, and DUNE.

Inflation and Leptogenesis in a $U(1)$enhanced supersymmetric model
arXiv:1706.09707 Phys.Rev. D100 (2019) 015002
by: Ahn, Y.H. (IBS, Daejeon)
Abstract: Motivated by the flavored PecceiQuinn symmetry for unifying flavor physics and string theory, we investigate a supersymmetric extension of standard model (SM) for an explanation of inflation and leptogenesis by introducing $U(1)$ symmetries such that the $U(1)$$[gravity]^2$ anomalyfree condition together with the SM flavor structure demands additional sterile neutrinos as well as no axionic domainwall problem. Such additional neutrinos may play a crucial role as a bridge between leptogenesis and new neutrino oscillations along with high energy cosmic events. In a realistic moduli stabilization, we show that the moduli backreaction effect on the inflationary potential leads to the energy scale of inflation with the inflaton mass in a way that the power spectrum of the curvature perturbation and the scalar spectral index are to be well fitted with the latest Planck observation. We suggest that a new leptogenesis scenario could naturally be implemented via AffleckDine mechanism. So we show that the resultant baryon asymmetry, constrained by the sum of active neutrino masses and new high energy neutrino oscillations, crucially depends on the reheating temperature $T_{\rm reh}$. And we show that the model has a preference on $T_{\rm reh}\sim10^3$ TeV, which is compatible with the required $T_{\rm reh}$ to explain the baryon asymmetry of the Universe.
