
Neutron Star Stability in Light of the Neutron Decay Anomaly. (arXiv:1811.06546v1 [hepph])
Authors: Benjamin Grinstein, Chris Kouvaris, Niklas Grønlund Nielsen
A recent proposal suggests that experimental discrepancies on the lifetime of
neutrons can be resolved if neutrons decay to dark matter. At the same time it
has been demonstrated that such a decay mode would soften the nuclear equation
of state resulting in neutron stars with a maximum mass much below currently
observed ones. In this paper we demonstrate that appropriate dark matterbaryon
interactions can accommodate neutron stars with mass above 2 solar masses. We
also show that dark matter selfinteractions could also help neutrons stars
reach 2 solar masses provided that dark matter is of asymmetric nature.

SelfInteracting Dark Matter Through the Majoron Portal. (arXiv:1811.06619v1 [hepph])
Authors: Arvind Rajaraman, Jordan Smolinsky
We examine the phenomenology of the majoron portal: a simplified model of
fermionic dark matter coupled to a light scalar mediator carrying lepton number
2. We find that the mediator can be very light and still consistent with
laboratory and cosmological bounds. This model satisfies the thermal relic
condition for natural values of dimensionless coupling constants and admits a
mediator in the $10  100 ~\text{MeV}$ mass range favored by small scale
structure observations. As such, this model provides an excellent candidate for
selfinteracting dark matter.

Physics Potentials of the HyperKamiokande Second Detector in Korea. (arXiv:1811.06682v1 [hepex])
Authors: SeonHee Seo (for the HyperKamiokande ProtoCollaboration)
HyperKamiokande (HyperK) succeeds the very successful SuperK experiment
and will consist of a large detector filled with 260~kton purified water and
equipped with 40\% photocoverage. Physics program of HyperK is broad,
covering from particle physics to astrophysics and astronomy. The HyperK
1$^{st}$ detector will be built in Japan, and the 2$^{nd}$ detector is
considered to be built in Korea because locating the 2$^{nd}$ detector in Korea
improves physics sensitivities in most cases thanks to the longer baseline
($\sim$1,100~km) and larger overburden ($\sim$1,000~m) for Korean candidate
sites. In this talk, we present overview and physics potentials of the HyperK
2$^{nd}$ detector in Korea.

Confronting hadronic tau decays with nonleptonic kaon decays. (arXiv:1811.06706v1 [hepph])
Authors: Antonio Rodríguez Sánchez, Antonio Pich
In the chiral limit, the $D=6$ contribution to the Operator Product Expansion
(OPE) of the $\mathrm{VVAA}$ correlator of quark currents only depends on two
vacuum condensates, which can be related to hadronic matrix elements associated
to CP violation in nonleptonic kaon decays. We use those relations to
determine $\langle(\pi\pi)_{I=2}\mathcal{Q}_{8}K\rangle$, using the updated
ALEPH spectral functions. Alternatively, we use those relations in the opposite
direction. Taking the values of the matrix elements from the lattice to obtain
the $D=6$ vacuum elements provides a new shortdistance constraint which allows
for an inclusive determination of $f_{\pi}$ and an updated value for the $D=8$
condensate.

Correlation observables in $\Upsilon D$ pair production at the LHC within the parton Reggeization approach. (arXiv:1811.06733v1 [hepph])
Authors: Anton Karpishkov, Maxim Nefedov, Vladimir Saleev
We study angular correlations in associated hadroproduction of $\Upsilon(1S)$
with the $D^{\pm}$ and $D^0$mesons at the LHC in the Leading Order of the
parton Reggeization approach. Hadronization of $b\bar{b}$pair to
$\Upsilon(1S)$ is described within the NRQCDfactorization framework.
Production of $D$mesons is described in the fragmentation model with
scaledependent fragmentaion functions. We have found good agreement with LHCb
data for various differential distributions, except for the case of spectra on
azimuthal angle differences at the small $\triangle\varphi$ values. The total
crosssection in our Single Parton Scattering model, calculated under
conservative assumptions, accounts for almost one half of observed
crosssection, thus dramatically shrinking the room for Double Parton
Scattering mechanism.

Muonelectron scattering at NLO. (arXiv:1811.06743v1 [hepph])
Authors: Massimo Alacevich, Carlo M. Carloni Calame, Mauro Chiesa, Guido Montagna, Oreste Nicrosini, Fulvio Piccinini
We consider the process of muonelectron elastic scattering, which has been
proposed as an ideal framework to measure the running of the electromagnetic
coupling constant at spacelike momenta and determine the leadingorder
hadronic contribution to the muon $g2$ (MUonE experiment). We compute the
nexttoleading (NLO) contributions due to QED and purely weak corrections and
implement them into a fully differential Monte Carlo event generator, which is
available for first experimental studies. We show representative
phenomenological results of interest for the MUonE experiment and examine in
detail the impact of the various sources of radiative corrections under
different selection criteria, in order to study the dependence of the NLO
contributions on the applied cuts. The study represents the first step towards
the realisation of a highprecision Monte Carlo code necessary for data
analysis.

Analysis of the durationhardness ratio plane of gammaray bursts using skewed distributions. (arXiv:1811.06745v1 [astroph.HE])
Authors: Mariusz Tarnopolski
The two widely accepted classes of gammaray bursts (GRBs), short and long,
are with confidence ascribed to mergers of compact objects and collapse of
massive stars, respectively. A third, intermediate/soft class, remains
putative. Its existence was claimed based on univariate and bivariate analyses
of GRB observables modeled with Gaussian distributions. This, however, may not
be the appropriate approach, as it has been already shown that the univariate
distributions of durations are better described by mixtures of two skewed
components rather than three Gaussian ones.
This paper investigates whether data in the durationhardness ratio plane is
better modeled by mixtures of skewed bivariate distributions than by normal
ones. The archival data set of the Compton GammaRay Observatory/BATSE and
Fermi/GBM data from the most recent catalogue release are examined. The
preferred model is chosen based on two information criteria, Akaike ($AIC$) and
Bayesian ($BIC$). It is found that the best description is given by a
twocomponent mixture of skewed Student$t$ distributions, which outperforms
any other model considered. This implies that the distribution of the studied
parameters is intrinsically skewed, introducing spurious Gaussian components,
and hence the third class is unlikely to be a real phenomenon. Its existence,
based on statistical inference, is therefore rejected as unnecessary to explain
the observations.

$\piN$ DrellYan process in TMD factorization. (arXiv:1811.06813v1 [hepph])
Authors: Xiaoyu Wang, Zhun Lu
This article presents the review of the current understanding on the
pionnucleon DrellYan process from the point of view of the TMD factorization.
Using the evolution formalism for the unpolarized and polarized TMD
distributions developed recently, we provide the theoretical expression of the
relevant physical observables, namely, the unpolarized cross section, the
Sivers asymmetry, and the $\cos2\phi$ asymmetry contributed by the double
BoerMulders effect. The corresponding phenomenology, particularly at the
kinematical configuration of the COMPASS $\pi N$ DrellYan, is displayed
numerically.

Paleodetectors: Searching for Dark Matter with Ancient Minerals. (arXiv:1811.06844v1 [astroph.CO])
Authors: Andrzej K. Drukier, Sebastian Baum, Katherine Freese, Maciej Górski, Patrick Stengel
Recently, we proposed paleodetectors as a method for the direct detection of
Weakly Interacting Massive Particle (WIMP) dark matter. In paleodetectors, one
would search for the persistent traces left by dark matternucleon interactions
in ancient minerals. Thanks to the large integration time of paleodetectors,
relatively small target masses suffice to obtain exposures, i.e. the product of
integration time and target mass, much larger than what is feasible in the
conventional direct detection approach. Here, we discuss the paleodetector
proposal in detail, in particular, a range of background sources. For lowmass
WIMPs with masses $m_\chi\lesssim10\,$GeV, the largest contribution to the
background budget comes from nuclear recoils induced by coherent scattering of
solar neutrinos. For heavier WIMPs, the largest background source is nuclear
recoils induced by fast neutrons created by heavy radioactive contaminants,
particularly $^{238}$U; neutrons can arise in spontaneous fission or from
$\alpha$particles created in $^{238}$U decays. We also discuss the challenges
of mineral optimization, specifically the determination of readily available
minerals from rocks in deep boreholes which are able to record persistent
damage from nuclear recoils. In order to suppress backgrounds induced by
radioactive contaminants, we propose to use minerals found in marine evaporites
or in ultrabasic rocks. We estimate the sensitivity of paleodetectors to
spinindependent and spindependent WIMPnucleus interactions. In all
interaction cases considered here, the sensitivity to lowmass WIMPs with
masses $m_\chi\lesssim10\,$GeV extends to WIMPnucleon cross sections many
orders of magnitude smaller than current upper limits. For heavier WIMPs with
masses $m_\chi\gtrsim30\,$GeV cross sections a factor of a few to $\sim100$
smaller than current upper limits can be probed by paleodetectors. [Abridged]

Vacuum structure of the leftright symmetric model. (arXiv:1811.06869v1 [hepph])
Authors: P.S. Bhupal Dev, Rabindra N. Mohapatra, Werner Rodejohann, XunJie Xu
The leftright symmetric model (LRSM), originally proposed to explain parity
violation in low energy processes, has since emerged as an attractive framework
for light neutrino masses via the seesaw mechanism. The scalar sector of the
minimal LRSM consists of an $SU(2)$ bidoublet, as well as left and
righthanded weak isospin triplets, thus making the corresponding vacuum
structure much more complicated than that of the Standard Model. In particular,
the desired ground state of the Higgs potential should be a charge conserving,
and preferably global, minimum with parity violation at low scales. We show
that this is not a generic feature of the LRSM potential and happens only for a
small fraction of the parameter space of the potential. We also analytically
study the potential for some simplified cases and obtain useful conditions
(though not necessary) to achieve successful symmetry breaking. We then carry
out a detailed statistical analysis of the minima of the Higgs potential using
numerical minimization and find that for a large fraction of the parameter
space, the potential does not have a good vacuum. Imposing the analytically
obtained conditions, we can readily find a small part of the parameter space
with good vacua. Consequences for some scalar masses are also discussed.

$\tau$ decay into a pseudoscalar and an axialvector meson. (arXiv:1811.06875v1 [hepph])
Authors: L. R. Dai, L. Roca, E. Oset
We study theoretically the decay $\tau^ \to \nu_\tau P^ A$, with $P^$ a
$\pi^$ or $K^$ and $A$ an axialvector resonance $b_1(1235)$, $h_1(1170)$,
$h_1(1380)$, $a_1(1260)$, $f_1(1285)$ or any of the two poles of the
$K_1(1270)$. The process proceeds through a triangle mechanism where a vector
meson pair is first produced from the weak current and then one of the vectors
produces two pseudoscalars, one of which reinteracts with the other vector to
produce the axial resonance. For the initial weak hadronic production we use a
recent formalism to account for the hadronization after the initial
quarkantiquark pair produced from the weak current, which explicitly filters
Gparity states and obtain easy analytic formulas after working out the angular
momentum algebra. The model also takes advantage of the chiral unitary theories
to evaluate the vectorpseudoscalar amplitudes, where the axialvector
resonances were obtained as dynamically generated from the VP interaction. We
make predictions for invariant mass distribution and branching ratios for the
channels considered.

Twophoton exchange in nonrelativistic approximation. (arXiv:1811.06928v1 [hepph])
Authors: Dmitry Borisyuk, Alexander Kobushkin
We calculate twophoton exchange amplitudes for the elastic electronhadron
scattering in the nonrelativistic approximation, and obtain analytical formulae
for them. Numerical calculations are performed for proton and $^3$He targets.
Comparing our numerical results with relativistic calculations, we find that
the real part of the amplitude is described well at moderate $Q^2$, but the
imaginary part strongly differs from the relativistic result. Thus the
nonrelativistic approximation should not be used for calculation of observables
which depend on the imaginary part of the amplitude, such as singlespin
asymmetries.

Angular decorrelations in $\gamma + 2 jet$ events at high energies in the parton Reggeization approach. (arXiv:1811.06942v1 [hepph])
Authors: Anton Karpishkov, Vladimir Saleev, Alexandra Shipilova
We discuss associated production of prompt photon plus two jets at high
energies in the framework of the parton Reggeization approach, which is based
on multiRegge factorization of hard processes and Lipatov's effective theory
of Reggeized gluons and quarks. In this approach, initialstate offshell
effects and transverse momenta of initial partons are included in a
gaugeinvariant way. We compute transverse momentum spectra of prompt photons
in inclusive $\gamma$production, in $\gamma + jet$ and $\gamma+2jets$ events,
and azimuthal angle difference spectrum in $\gamma + 2 jet$ events. We compare
our results with the experimental data from D0 Collaboration at Tevatron and
with the theoretical predictions obtained in conventional NLO approximation of
the collinear parton model. The relation between SPS and DPS production
mechanisms is also studied.

Exploring Inert Scalars at CLIC. (arXiv:1811.06952v1 [hepph])
Authors: Jan Kalinowski, Wojciech Kotlarski, Tania Robens, Dorota Sokolowska, Aleksander Filip Zarnecki
We investigate the prospect of discovering the Inert Doublet Model scalars at
CLIC. As signal processes, we consider the pairproduction of inert scalars,
namely e+e > H+H and e+e > AH, followed by decays of charged scalars H+
and neutral scalars A into leptonic final states and missing transverse energy.
We focus on signal signatures with two muons or an electron and a muon pair in
the final state. A number of selected benchmark scenarios that cover the range
of possible collider signatures of the IDM are considered. For the suppression
of SM background with the same visible signature, multivariate analysis methods
are employed. For several benchmark points discovery is already possible at
lowenergy stage of CLIC. Prospects of investigating scenarios that are only
accessible at higher collider energies are also discussed.

Gluequark Dark Matter. (arXiv:1811.06975v1 [hepph])
Authors: Roberto Contino, Andrea Mitridate, Alessandro Podo, Michele Redi
We introduce the gluequark Dark Matter candidate, an accidentally stable
bound state made of adjoint fermions and gluons from a new confining gauge
force. Such scenario displays an unusual cosmological history where
perturbative freezeout is followed by a nonperturbative reannihilation
period with possible entropy injection. When the gluequark has electroweak
quantum numbers, the critical density is obtained for masses as large as PeV.
Independently of its mass, the size of the gluequark is determined by the
confinement scale of the theory, leading at low energies to annihilation rates
and elastic cross sections which are large for particle physics standards and
potentially observable in indirect detection experiments.

Spin3/2 dark matter in a simple $t$channel model. (arXiv:1705.05149v3 [hepph] UPDATED)
Authors: Mohammed Omer Khojali, Ashok Goyal, Mukesh Kumar, Alan S. Cornell
We consider a spin3/2 fermionic dark matter (DM) particle interacting with
the Standard Model quarks through the exchange of a charged and coloured scalar
or vector mediator in a simple $t$channel model. It is found that for the
vector mediator case, almost the entire parameter space allowed by the observed
relic density is already ruled out by the direct detection LUX data. No such
bounds exist on the interaction mediated by scalar particles. Monojet + missing
energy searches at the Large Hadron Collider provide the most stringent bounds
on the parameters of the model for this case. The collider bounds put a lower
limit on the allowed DM masses.

Directly Detecting MeVscale Dark Matter via Solar Reflection. (arXiv:1708.03642v3 [hepph] UPDATED)
Authors: Haipeng An, Maxim Pospelov, Josef Pradler, Adam Ritz
If dark matter (DM) particles are lighter than a few MeV/$c^2$ and can
scatter off electrons, their interaction within the solar interior results in a
considerable hardening of the spectrum of galactic dark matter received on
Earth. For a large range of the mass vs. cross section parameter space, $\{m_e,
\sigma_e\}$, the "reflected" component of the DM flux is far more energetic
than the endpoint of the ambient galactic DM energy distribution, making it
detectable with existing DM detectors sensitive to an energy deposition of
$1010^3$ eV. After numerically simulating the small reflected component of the
DM flux, we calculate its subsequent signal due to scattering on detector
electrons, deriving new constraints on $\sigma_e$ in the MeV and subMeV range
using existing data from the XENON10/100, LUX, PandaXII, and XENON1T
experiments, as well as making projections for future low threshold direct
detection experiments.

Search for sterile neutrinos in a universe of vacuum energy interacting with cold dark matter. (arXiv:1712.03148v2 [astroph.CO] UPDATED)
Authors: Lu Feng, JingFei Zhang, Xin Zhang
We investigate the cosmological constraints on sterile neutrinos in a
universe in which vacuum energy interacts with cold dark matter by using latest
observational data. We focus on two specific interaction models, $Q=\beta
H\rho_{\rm v}$ and $Q=\beta H\rho_{\rm c}$. To overcome the problem of
largescale instability in the interacting dark energy scenario, we employ the
parametrized postFriedmann (PPF) approach for interacting dark energy to do
the calculation of perturbation evolution. The observational data sets used in
this work include the Planck 2015 temperature and polarization data, the baryon
acoustic oscillation measurements, the typeIa supernova data, the Hubble
constant direct measurement, the galaxy weak lensing data, the redshift space
distortion data, and the Planck lensing data. Using the alldata combination,
we obtain $N_{\rm eff}<3.522$ and $m_{\nu,{\rm sterile}}^{\rm eff}<0.576$ eV
for the $Q=\beta H\rho_{\rm v}$ model, and $N_{\rm
eff}=3.204^{+0.049}_{0.135}$ and $m_{\nu,{\rm sterile}}^{\rm
eff}=0.410^{+0.150}_{0.330}$ eV for the $Q=\beta H\rho_{\rm c}$ model. The
latter indicates $\Delta N_{\rm eff}>0$ at the 1.17$\sigma$ level and a nonzero
mass of sterile neutrino at the 1.24$\sigma$ level. In addition, for the
$Q=\beta H\rho_{\rm v}$ model, we find that $\beta=0$ is consistent with the
current data, and for the $Q=\beta H\rho_{\rm c}$ model, we find that $\beta>0$
is obtained at more than 1$\sigma$ level.

Statistical approach of pion parton distributions from DrellYan process. (arXiv:1802.03153v3 [hepph] UPDATED)
Authors: Claude Bourrely, Jacques Soffer
The quantum statistical approach proposed more than one decade ago was used
to determine the parton distributions for the proton by considering a large set
of accurate Deep Inelastic Scattering experimental results. We propose to
extend this work to extract the parton distributions for the pion by using data
on lepton pair production from various experiments. This global nexttoleading
order QCD analysis leads to a good description of several DrellYan $\pi^ W$
data. The resulting parton distributions are compared with earlier
determinations. We will also discuss the difference between nucleon and pion
structure in the same approach.

Electroweak interaction beyond the Standard Model and Dark Matter in the Tangent Bundle Quantum Field Theory. (arXiv:1802.03228v2 [hepph] UPDATED)
Authors: Joachim Herrmann
A generalized theory of electroweak interaction is developed based on the
underlying geometrical structure of the tangent bundle with symmetries arising
from transformations of tangent vectors along the fiber axis at a fixed
spacetime point, leaving the scalar product invariant. Transformations with
this property are given by the $SO(3,1)$ group with the little groups
$SU(2),E^{c}(2)$ and $SU(1,1)$ where the group $E^{c}(2)$ is the central
extended group of the Euclidian group $E(2).$ Electroweak interaction beyond
the standard model (SM) is described by the transformation group $SU(2)\otimes
E^{c}\mathbf{(}2)$ without a priori introduction of a phenomenologically
determined gauge group. The Laplacian on this group yields the known internal
quantum numbers of isospin and hypercharge, but in addition the extra
$E^{c}$charge $\varkappa $ and the family quantum number $n$ which explains
the existence of families in the SM. The connection coefficients deliver the SM
gauge potentials but also hypothetical gauge bosons and other hypothetical
particles as well as candidate Dark Matter particles are predicted. It is shown
that the interpretation of the $SO(3,1)$ connection coefficients as elctroweak
gauge potentials is compatible with teleparallel gauge gravity theory based on
the translational group.

Polarization observables and Tnoninvariance in the weak charged current induced electron proton scattering. (arXiv:1802.04469v2 [hepph] UPDATED)
Authors: A. Fatima, M. Sajjad Athar, S. K. Singh
In this work, we have studied the total scattering cross section ($\sigma$),
differential scattering cross section ($d\sigma/dQ^2$) as well as the
longitudinal ($P_L(E_e,Q^2)$), perpendicular ($P_P(E_e,Q^2)$), and transverse
($P_T(E_e,Q^2)$) components of the polarization of the final hadron ($n$, $
\Lambda$ and $\Sigma^0$) produced in the electron proton scattering induced by
the weak charged current. We have not assumed Tinvariance which allows the
transverse component of the hadron polarization perpendicular to the production
plane to be nonzero. The numerical results are presented for all the above
observables and their dependence on the axial vector form factor and the weak
electric form factor are discussed. The present study enables the determination
of the axial vector nucleonhyperon transition form factors at high $ Q^2$ in
the strangeness sector which can provide test of the symmetries of the weak
hadronic currents like Tinvariance and SU(3) symmetry while assuming the
hypothesis of conserved vector current and partial conservation of axial vector
current.

Mapping the sensitivity of hadronic experiments to nucleon structure. (arXiv:1803.02777v3 [hepph] UPDATED)
Authors: BoTing Wang, T. J. Hobbs, Sean Doyle, Jun Gao, TieJiun Hou, Pavel M. Nadolsky, Fredrick I. Olness
Determinations of the proton's collinear parton distribution functions (PDFs)
are emerging with growing precision due to increased experimental activity at
facilities like the Large Hadron Collider. While this copious information is
valuable, the speed at which it is released makes it difficult to quickly
assess its impact on the PDFs, short of performing computationally expensive
global fits. As an alternative, we explore new methods for quantifying the
potential impact of experimental data on the extraction of proton PDFs. Our
approach relies crucially on the Hessian correlation between theorydata
residuals and the PDFs themselves, as well as on a newly defined quantity 
the sensitivity  which represents an extension of the correlation and
reflects both PDFdriven and experimental uncertainties. This approach is
realized in a new, publicly available analysis package PDFSense, which operates
with these statistical measures to identify particularly sensitive experiments,
weigh their relative or potential impact on PDFs, and visualize their detailed
distributions in a space of the parton momentum fraction $x$ and factorization
scale $\mu$. This tool offers a new means of understanding the influence of
individual measurements in existing fits, as well as a predictive device for
directing future fits toward the highest impact data and assumptions. Along the
way, many new physics insights can be gained or reinforced. As one of many
examples, PDFSense is employed to rank the projected impact of new LHC
measurements in jet, vector boson, and $t\bar{t}$ production and leads us to
the conclusion that inclusive jet production at the LHC has a potential for
playing an indispensable role in future PDF fits. These conclusions are
independently verified by preliminarily fitting this experimental information
and investigating the constraints they supply using the Lagrange multiplier
technique.

Nonperturbative Renormalization of Operators in NearConformal Systems Using Gradient Flows. (arXiv:1806.01385v3 [heplat] UPDATED)
Authors: Andrea Carosso, Anna Hasenfratz, Ethan T. Neil
We propose a continuous real space renormalization group transformation based
on gradient flow, allowing for a numerical study of renormalization without the
need for costly ensemble matching. We apply our technique in a pilot study of
SU$(3)$ gauge theory with $N_f = 12$ fermions in the fundamental
representation, finding the mass anomalous dimension to be $\gamma_m =
0.23(6)$, consistent with other perturbative and lattice estimates. We also
present the first lattice calculation of the nucleon anomalous dimension in
this theory, finding $\gamma_N = 0.05(5)$.

Natural Inflation with a periodic nonminimal coupling. (arXiv:1806.05511v3 [astroph.CO] UPDATED)
Authors: Ricardo Z.Ferreira, Alessio Notari, Guillem Simeon
Natural inflation is an attractive model for primordial inflation, since the
potential for the inflaton is of the pseudo NambuGoldstone form,
$V(\phi)=\Lambda^4 [1+\cos (\phi/f)]$, and so is protected against radiative
corrections. Successful inflation can be achieved if $f \gtrsim {\rm few}\,
M_{P}$ and $\Lambda \sim m_{GUT}$ where $\Lambda$ can be seen as the strong
coupling scale of a given nonabelian gauge group. However, the latest
observational constraints put natural inflation in some tension with data. We
show here that a nonminimal coupling to gravity $\gamma^2(\phi) R$, that
respects the symmetry $\phi\rightarrow \phi+2 \pi f$ and has a simple form,
proportional to the potential, can improve the agreement with cosmological
data. Moreover, in certain cases, satisfactory agreement with the Planck 2018
TT, TE, EE and low P data can be achieved even for a periodicity scale of
approximately $M_p$.

Consistency of a gauged twoHiggsdoublet model: Scalar sector. (arXiv:1806.05632v2 [hepph] UPDATED)
Authors: Abdesslam Arhrib, WeiChih Huang, Raymundo Ramos, YueLin Sming Tsai, TzuChiang Yuan
We study the theoretical and phenomenological constraints imposed on the
scalar sector of the gauged two Higgs doublet model proposed recently as a
variant of the popular inert Higgs doublet model of dark matter. The
requirements of treelevel vacuum stability and perturbative unitarity in the
scalar sector are analyzed in detail. Furthermore, taking into account the
constraints from the 125 GeV Higgs boson measurements at the Large Hadron
Collider, we map out the allowed ranges for the fundamental parameters of the
scalar potential in the model.

Second class currents and T violation in quasielastic neutrino and antineutrino scattering from nucleons. (arXiv:1806.08597v2 [hepph] UPDATED)
Authors: A. Fatima, M. Sajjad Athar, S. K. Singh
The effect of the second class currents with and without time reversal
invariance has been studied in the quasielastic production of nucleons and
hyperons induced by neutrinos and antineutrinos from the nucleons. The
numerical results are presented for the total scattering cross
section~($\sigma$) as well as for the longitudinal, perpendicular and
transverse components of the polarization of the final baryons ($p$, $n$,
$\Lambda$, $\Sigma^$, $\Sigma^0$) and muon produced in the quasielastic
(anti)neutrinonucleon scattering induced by the weak charged current. In the
case of the production of $\Lambda$ hyperon, which is the most suitable
candidate for making the polarization measurements, we have also calculated the
$Q^2$ dependence of the polarization observables and the differential
scattering cross section ($d\sigma/dQ^2$). The measurement of the polarization
observables and their $Q^2$ dependence provides an independent way to determine
the nucleonhyperon transition form factors at high $Q^2$ which can provide
tests of the symmetries of the weak hadronic currents like Ginvariance, T
invariance and SU(3) symmetry.

Matter parametric neutrino flavor transformation through Rabi resonances. (arXiv:1807.10219v2 [hepph] UPDATED)
Authors: Lei Ma (UNM), Shashank Shalgar (LANL), Huaiyu Duan (UNM)
We consider the flavor transformation of neutrinos through oscillatory matter
profiles. We show that the neutrino oscillation Hamiltonian in this case
describes a Rabi system with an infinite number of Rabi modes. We further show
that, in a given physics problem, the majority of the Rabi modes have too small
amplitudes to be relevant. We also go beyond the rotating wave approximation
and derive the relative detuning of the Rabi resonance when multiple Rabi modes
with small amplitudes are present. We provide an explicit criterion of whether
an offresonance Rabi mode can affect the parametric flavor transformation of
the neutrino.

Heavy Higgs boson decays in the alignment limit of the 2HDM. (arXiv:1808.01472v3 [hepph] UPDATED)
Authors: Bohdan Grzadkowski, Howard E. Haber, Odd Magne Ogreid, Per Osland
The Standard Model (SM)like couplings of the observed Higgs boson impose
strong constraints on the structure of any extended Higgs sector. We consider
the theoretical properties and the phenomenological implications of a generic
two Higgs doublet model (2HDM). This model constitutes a simple and attractive
extension of the SM that is consistent with the observation of the SMlike
Higgs boson and precision electroweak observables, while providing a potential
new source of CPviolation. In this paper we focus on the socalled Higgs
alignment limit of the generic 2HDM, where the neutral scalar field~$H_1$, with
the treelevel couplings of the SM Higgs boson, is a mass eigenstate that is
aligned in field space with the direction of the Higgs vacuum expectation
value. The properties of the two other heavier neutral Higgs scalars, $H_2$ and
$H_3$, in the alignment limit of the 2HDM are also elucidated. It is shown that
the couplings of $H_2$ and $H_3$ in the alignment limit are tightly constrained
and correlated. For example, in the exact alignment limit at tree level, for
bosonic final states $\text{BR}(H_{2,3} \to W^+W^, ZZ, H_1 Z) = 0$ and
$\text{BR}(H^\pm \to W^\pm H_1) = 0$, whereas for fermionic final states
$\Gamma(H_2 \to f\bar f)/\Gamma(H_3 \to f\bar f) \sim M_2/M_3$ (where
$M_\alpha$ is the mass of $H_\alpha$). In some cases, the results of the
alignment limit differ depending on whether or not alignment is achieved via
the decoupling of heavy scalar states. In particular, in the exact alignment
limit without decoupling $\text{BR}(H_{2,3}\to H_1 H_1)=0$, whereas these
branching ratios are nonzero in the decoupling regime. Observables that could
be used to test the alignment scenario at the LHC are defined and discussed.
The couplings of the Higgs bosons away from their exact alignment values are
determined to leading order, and some consequences are elucidated.

Footprints of New Physics in $b\to c\tau\nu$ Transitions. (arXiv:1808.03565v2 [hepph] UPDATED)
Authors: ZhuoRan Huang, Ying Li, CaiDian Lu, M. Ali Paracha, Chao Wang
In this work, we perform a combined analysis of the $R(D)$, $R(D^*)$, and
$R(J/\psi)$ anomalies in a modelindependent manner based on the general
framework of the fourfermion effective field theory, paying special attention
to the use of the hadronic form factors. For the $B\to D(D^*)$ transition form
factors, we use the HQET parametrization that includes the higher order
corrections of $\mathcal{O}(\alpha_s,\Lambda_{\mathrm{QCD}}/m_{b,c})$ and was
determined recently from a fit to lattice QCD and lightcone sum rule results
in complementary kinematical regions of the momentum transfer. For the $B_c\to
J/\psi(\eta_c)$ transitions, we use the form factors calculated in the
covariant lightfront quark model, which are found to be well consistent with
the preliminary lattice results. With this particular treatment of hadronic
matrix elements, in our analysis the two classes of vector operators are shown
to be the most favored single new physics (NP) operators by the current
experimental constraints within $2\sigma$ and the LEP1 data on $Br(B_c\to
\tau\nu)$ as well as the minimum $\chi^2$ fit, while the tensor operator is
also allowed but severely constrained, and the scalar ones are excluded. Using
the favored ranges and fitted values of the Wilson coefficients of the single
NP operators, we also give a prognosis for the physical observables such as the
ratios of decay rates ($R(D(D^*)), R(J/\psi(\eta_c))$) and other polarized
observables as well as the $q^2$ distributions.

Symmetries and Mass Degeneracies in the Scalar Sector. (arXiv:1808.08629v2 [hepph] UPDATED)
Authors: Howard E. Haber, O.M. Ogreid, P. Osland, M.N. Rebelo
We explore some aspects of models with two and three SU(2) scalar doublets
that lead to mass degeneracies among some of the physical scalars. In Higgs
sectors with two scalar doublets, the exact degeneracy of scalar masses,
without an artificial finetuning of the scalar potential parameters, is
possible only in the case of the inert doublet model (IDM), where the scalar
potential respects a global U(1) symmetry that is not broken by the vacuum. In
the case of three doublets, we introduce and analyze the replicated inert
doublet model, which possesses two inert doublets of scalars. We then
generalize this model to obtain a scalar potential, first proposed by Ivanov
and Silva, with a CP4 symmetry that guarantees the existence of pairwise
degenerate scalar states among two pairs of neutral scalars and two pairs of
charged scalars. Here, CP4 is a generalized CP symmetry with the property that
(CP4)^n is the identity operator only for integer n values that are multiples
of 4. The form of the CP4symmetric scalar potential is simplest when expressed
in the Higgs basis, where the neutral scalar field vacuum expectation value
resides entirely in one of the scalar doublet fields. The symmetries of the
model permit a term in the scalar potential with a complex coefficient that
cannot be removed by any redefinition of the scalar fields within the class of
Higgs bases (in which case, we say that no real Higgs basis exists). We
demonstrate that it is possible to physically distinguish between the existence
or nonexistence of a real Higgs basis in three doublet scalar models governed
by a CP4symmetric scalar potential and vacuum. A striking feature of the
CP4symmetric model is that it preserves CP even in the absence of a real Higgs
basis, as illustrated by the cancellation of the contributions to the CP
violating form factors of the effective ZZZ and ZWW vertices.

New predictions for $\Lambda_b\to\Lambda_c$ semileptonic decays and tests of heavy quark symmetry. (arXiv:1808.09464v2 [hepph] UPDATED)
Authors: Florian U. Bernlochner, Zoltan Ligeti, Dean J. Robinson, William L. Sutcliffe
The heavy quark effective theory makes model independent predictions for
semileptonic $\Lambda_b \to \Lambda_c$ decays in terms of a small set of
parameters. No subleading IsgurWise function occurs at order $\Lambda_{\rm
QCD}/m_{c,b}$, and only two subsubleading functions enter at order
$\Lambda_{\rm QCD}^2/m_c^2$. These features allow us to fit the form factors
and decay rates calculated up to order $\Lambda_{\rm QCD}^2/m_c^2$ to LHCb data
and lattice QCD calculations. We derive a significantly more precise standard
model prediction for the ratio ${\cal B}(\Lambda_b\to \Lambda_c \tau\bar\nu) /
{\cal B}(\Lambda_b\to \Lambda_c \mu\bar\nu)$ than prior results, and find the
expansion in $\Lambda_{\rm QCD}/m_c$ wellbehaved, addressing a longstanding
question. Our results allow more precise and reliable calculations of
$\Lambda_b\to \Lambda_c\ell\bar\nu$ rates, and are systematically improvable
with better data on the $\mu$ (or $e$) modes.

A Method to Determine $V_{cb}$ at the Weak Scale in Top Decays at the LHC. (arXiv:1810.09424v2 [hepph] UPDATED)
Authors: P. F. Harrison, V. E. Vladimirov
Until now, the Cabibbo Kobayashi Maskawa matrix element, $V_{cb}$, has
always been measured in $B$ decays, i.e.~at an energy scale $q_b\sim
\frac{m_b}{2}$, far below the weak scale. We consider here the possibility of
measuring it close to the weak scale, at $q_W\sim m_W$, in top decays at the
Large Hadron Collider (LHC). Our proposed method would use data from the LHC
experiments in hadronic top decays $t\rightarrow bW\rightarrow b\overline{b}
c$, tagged by the semileptonic decay of the associated top. We estimate the
uncertainty of such a measurement, as a function of present and potential
future experimental jet flavourtagging performances, and conclude that first
measurements using the data collected during 2016  2018 could yield a
fractional error on \Vcb\ of order 7\% per experiment. We also give projected
performances at higher luminosities, which could yield sensitivity to any
Standard Model running of \Vcb\ below the weak scale, if present.

Dark Energy and the Refined de Sitter Conjecture. (arXiv:1811.00554v2 [hepph] UPDATED)
Authors: Prateek Agrawal, Georges Obied
We revisit the phenomenology of quintessence models in light of the recently
refined version of the de Sitter Swampland conjecture, which includes the
possibility of unstable de Sitter critical points. We show that models of
quintessence can evade previously derived lower bounds on $(1+w)$, albeit with
very finelytuned initial conditions. In the absence of such tuning or other
rolling quintessence fields, a field with mass close to Hubble is required,
which has a generic prediction for $(1+w)$. Slowroll single field inflation
models remain in tension. Other phenomenological constraints arising from the
coupling of the quintessence field with the Higgs or the QCD axion are
significantly relaxed.

Audible Axions. (arXiv:1811.01950v2 [hepph] UPDATED)
Authors: Camila S. Machado, Wolfram Ratzinger, Pedro Schwaller, Ben A. Stefanek
Conventional approaches to probing axions and axionlike particles (ALPs)
typically rely on a coupling to photons. However, if this coupling is extremely
weak, ALPs become invisible and are effectively decoupled from the Standard
Model. Here we show that such invisible axions, which are viable candidates for
dark matter, can produce a stochastic gravitational wave background in the
early universe. This signal is generated in models where the invisible axion
couples to a dark gauge boson that experiences a tachyonic instability when the
axion begins to oscillate. Incidentally, the same mechanism also widens the
viable parameter space for axion dark matter. Quantum fluctuations amplified by
the exponentially growing gauge boson modes source chiral gravitational waves.
For axion decay constants $f \gtrsim 10^{17}$ GeV, this signal is detectable by
either pulsar timing arrays or space/groundbased gravitational wave detectors
for a broad range of axion masses, thus providing a new window to probe
invisible axion models.

Unification of Flavor SU(3) Analyses of Heavy Hadron Weak Decays. (arXiv:1811.03480v2 [hepph] UPDATED)
Authors: XiaoGang He, YuJi Shi, Wei Wang
Flavor SU(3) analyses of heavy mesons and baryons hadronic charmless decays
can be formulated in two different forms. One is to construct the SU(3)
irreducible representation amplitude (IRA) by decomposing effective
Hamiltonian, and the other is to draw the topological diagrams (TDA). We study
various $B/D\to PP,VP,VV$, $B_c\to DP/DV$ decays, and twobody nonleptonic
decays of beauty/charm baryons, and demonstrate that when all terms are
included these two ways of analyzing the decay amplitudes are completely
equivalent. We clarify some confusions in drawing topological diagrams using
different ways of describing beauty/charm baryon states.

Elliptic flow fluctuations in central collisions of spherical and deformed nuclei. (arXiv:1811.03959v2 [nuclth] UPDATED)
Authors: Giuliano Giacalone
Elliptic flow ($v_2$) fluctuations in central heavyion collisions are direct
probes of the fluctuating geometry of the quarkgluon plasma, and, as such, are
strongly sensitive to any deviation from spherical symmetry in the shape of the
colliding nuclei. We investigate the consequences of nuclear deformation for
$v_2$ fluctuations, and we assess whether current models of medium geometry are
able to predict and capture such effects. Assuming linear hydrodynamic response
between $v_2$ and the eccentricity of the medium, $\varepsilon_2$, we perform
accurate comparisons between model calculations of $\varepsilon_2$ fluctuations
and STAR data on cumulants of elliptic flow, in central Au+Au and U+U
collisions. From these comparisons, we evince that the most distinct signatures
of nuclear deformation appear in the nonGaussianities of $v_2$ fluctuation,
and we show, in particular, that the nonGaussian $v_2$ fluctuations currently
observed in central Au+Au collisions are incompatible with model calculations
that implement a quadrupole coefficient of order 12\% in the $^{197}$Au nuclei.
Finally, we make robust predictions for the behavior of higherorder cumulants
of $v_2$ in collisions of nonspherical nuclei.

Dark Matter with Stuckelberg Axions. (arXiv:1811.05792v2 [hepph] UPDATED)
Authors: Claudio Coriano, Paul H. Frampton, Nikos Irges, Alessandro Tatullo
We review a class of models which generalize the traditional PecceiQuinn
(PQ) axion solution by a St\"uckelberg pseudoscalar. Such axion models
represent a significant variant with respect to earlier scenarios where axion
fields were associated with global anomalies, because of the St\"uckelberg
field, which is essential for the cancellation of gauge anomalies in the
presence of extra $U(1)$ symmetries. The extra neutral currents associated to
these models have been investigated in the past in orientifold models with
intersecting branes, under the assumption that the St\"uckelberg scale was in
the multiTeV region. Such constructions, at the field theory level, are quite
general and can be interpreted as the fourdimensional field theory realization
of the GreenSchwarz mechanism of anomaly cancellation of string theory. We
present an overview of models of this type in the TeV/multi TeV range in their
original formulation and their recent embeddings into an ordinary GUT theory,
presenting an $E_6\times U(1)_X$ model as an example. In this case the model
contains two axions, the first corresponding to a PecceiQuinn axion, whose
misalignment takes place at the QCD phase transition, with a mass in the meV
region and which solves the strong CP problem. The second axion is ultralight,
in the $10^{20}10^{22}$ eV region, due to a misalignment and a decoupling
taking place at the GUT scale. The two scales introduced by the PQ solution,
the PQ breaking scale and the misalignment scale at the QCD hadron transition,
become the Planck and the GUT scales respectively, with a global anomaly
replaced by a gauge anomaly. The periodic potential and the corresponding
oscillations are related to a particle whose De Broglie wavelength can reach 10
kpc. Such a subgalactic scale has been deemed necessary in order to resolve
several dark matter issues at the astrophysical level.

Baryogenesis with the Berry phase. (arXiv:1811.06197v2 [hepth] UPDATED)
Authors: Seishi Enomoto, Tomohiro Matsuda
The spontaneous baryogenesis scenario explains how a baryon asymmetry can
develop while baryon violating interactions are still in thermal equilibrium.
However, generation of the chemical potential from the derivative coupling is
dubious since the chemical potential may not appear after the Legendre
transformation. The geometric phase (PancharatnamBerry phase) results from the
geometrical properties of the parameter space of the Hamiltonian, which is
calculated from the Berry connection. In this paper, using the formalism of the
Berry phase, we show that the chemical potential defined by the Berry
connection is consistent with the Legendre transformation. The framework of the
Berry phase is useful in explaining the mathematical background of the
spontaneous baryogenesis, and also is useful for calculating the asymmetry of
the nonthermal particle production in timedependent backgrounds. Using the
formalism, we show that the mechanism can be extended to more complex
situations.
