
The Weak Scale from Weak Gravity. (arXiv:1904.08426v1 [hepph])
Authors: Nathaniel Craig, Isabel Garcia Garcia, Seth Koren
We explore the prospects for bounding the weak scale using the weak gravity
conjecture (WGC), addressing the hierarchy problem by violating the
expectations of effective field theory. Building on earlier work by Cheung and
Remmen, we construct models in which a superextremal particle satisfying the
electric WGC for a new Abelian gauge group obtains some of its mass from the
Higgs, setting an upper bound on the weak scale as other UVinsensitive
parameters are held fixed. Avoiding undue sensitivity of the weak scale to the
parameters entering the bound implies that the superextremal particle must lie
at or below the weak scale. While the magnetic version of the conjecture
implies additional physics entering around the same scale, we demonstrate that
this need not correspond to a cutoff for the Higgs potential or otherwise
trivialize the bound. We stress that linking the WGC to the weak scale
necessarily involves new light particles coupled to the Higgs, implying a
variety of experimentally accessible signatures including invisible Higgs
decays and radiative corrections in the electroweak sector. These models also
give rise to natural dark matter candidates, providing additional paths to
discovery. In particular, collective effects in the dark matter plasma may
provide a telltale sign of the Abelian gauge group responsible for bounding the
weak scale.

Dark Matter Strikes Back at the Galactic Center. (arXiv:1904.08430v1 [astroph.HE])
Authors: Rebecca K. Leane, Tracy R. Slatyer
Statistical evidence has previously suggested that the Galactic Center GeV
Excess (GCE) originates largely from point sources, and not from annihilating
dark matter. We examine the impact of unmodeled source populations on
identifying the true origin of the GCE using nonPoissonian template fitting
(NPTF) methods. In a proofofprinciple example with simulated data, we
discover that unmodeled sources in the Fermi Bubbles can lead to a dark matter
signal being misattributed to point sources by the NPTF. We discover striking
behavior consistent with a mismodeling effect in the real Fermi data, finding
that large artificial injected dark matter signals are completely misattributed
to point sources. Consequently, we conclude that dark matter may provide a
dominant contribution to the GCE after all.

No strong $CP$ violation up to the oneloop level in a twoHiggsdoublet model. (arXiv:1904.08438v1 [hepph])
Authors: P.M. Ferreira, L. Lavoura
We put forward a twoHiggsdoublet model, furnished with a $Z_3$ symmetry,
wherein $CP$ is conserved in the dimensionfour terms of the Lagrangian and is
softly broken in the scalar potential.
The new particles of our model are one neutral scalar $H$, one neutral
pseudoscalar $A$, and two charged scalars $H^\pm$.
In our model the only locus of $CP$ violation is the CKM matrix.
Strong $CP$ violation is absent both at the tree and oneloop levels. We work
out the phenomenological constraints on our model, which features
flavourchanging neutral Yukawa interactions, showing that the new scalar
particles may in some cases be lighter than 500\,GeV.

Discovering True Muonium at LHCb. (arXiv:1904.08458v1 [hepph])
Authors: Xabier Cid Vidal, Philip Ilten, Jonathan Plews, Brian Shuve, Yotam Soreq
We study the potential of the LHCb experiment to discover, for the first
time, the $\mu^+\mu^$ true muonium bound state. We propose a search for the
vector $1^3S_1$ state, $\mathcal{T\!M}$, which kinetically mixes with the
photon and dominantly decays to $e^+e^$. We demonstrate that a search for
$\eta \to \gamma \mathcal{T\!M}$, $\mathcal{T\!M}\to e^+e^$ in a displaced
vertex can exceed a significance of 5 standard deviations assuming statistical
uncertainties. We present two possible searches: an inclusive search for the
$e^+e^$ vertex, and an exclusive search which requires an additional photon
and a reconstruction of the $\eta$ mass.

Portraying Double Higgs at the Large Hadron Collider. (arXiv:1904.08549v1 [hepph])
Authors: Jeong Han Kim, Minho Kim, Kyoungchul Kong, Konstantin T. Matchev, Myeonghun Park
We examine the discovery potential for double Higgs production at the high
luminosity LHC in the final state with two $b$tagged jets, two leptons and
missing transverse momentum. Although this dilepton final state has been
considered a difficult channel due to the large backgrounds, we argue that it
is possible to obtain sizable signal significance, by adopting a deep learning
framework making full use of the relevant kinematics along with the jet images
from the Higgs decay. For the relevant number of signal events we obtain a
substantial increase in signal sensitivity over existing analyses. We discuss
relative improvements at each stage and the correlations among the different
input variables for the neutral network. The proposed method can be easily
generalized to the semileptonic channel of double Higgs production, as well as
to other processes with similar final states.

Vacuum Decay in Real Time and Imaginary Time Formalisms. (arXiv:1904.08565v1 [hepth])
Authors: Mark P. Hertzberg, Masaki Yamada
We analyze vacuum tunneling in quantum field theory in a general formalism by
using the Wigner representation. In the standard instanton formalism, one
usually approximates the initial false vacuum state by an eigenstate of the
field operator, imposes Dirichlet boundary conditions on the initial field
value, and evolves in imaginary time. This approach does not have an obvious
physical interpretation. However, an alternative approach does have a physical
interpretation: in quantum field theory, tunneling can happen via classical
dynamics, seeded by initial quantum fluctuations in both the field and its
momentum conjugate, which was recently implemented in Ref. [1]. We show that
the Wigner representation is a useful framework to calculate and understand the
relationship between these two approaches. We find there are two, related,
saddle point approximations for the path integral of the tunneling process: one
corresponds to the instanton solution in imaginary time and the other one
corresponds to classical dynamics from initial quantum fluctuations in real
time. The classical approximation for the dynamics of the latter process is
justified only in a system with many degrees of freedom, as can appear in field
theory due to high occupancy of nucleated bubbles, while it is not justified in
single particle quantum mechanics, as we explain. We mention possible
applications of the real time formalism, including tunneling when the instanton
vanishes, or when the imaginary time contour deformation is not possible, which
may occur in cosmological settings.

The $\phi(2170)$ production in the process $\gamma p\to \eta \phi p$. (arXiv:1904.08569v1 [hepph])
Authors: ChenGuang Zhao, GuanYing Wang, GuanNan Li, En Wang, DeMin Li
We have studied the $\gamma p\to \eta \phi p$ reaction within the effective
Lagrangian approach, by considering the contribution of the intermediate state
$\phi(2170)$ production, and the background contributions of $t$channel
$\pi^0$ and $\eta$ mesons exchanges with the intermediate states $N$ and
$N(1535)$. Our calculations show that there may be a peak, at least a bump
structure around 2180 MeV associated to the resonance $\phi(2170)$ in the
$\eta\phi$ mass distribution. We suggest to search for the resonance
$\phi(2170)$ in this reaction, which would be helpful to shed light on its
nature.

Effective gauge theories of superfluidity with topological order. (arXiv:1904.08570v1 [hepth])
Authors: Yuji Hirono, Yuya Tanizaki
We discuss the lowenergy dynamics of superfluidity with topological order in
$(3+1)$ spacetime dimensions. We generalize a topological $BF$ theory by
introducing a nonsquare $K$ matrix, and this generalized $BF$ theory can
describe massless NambuGoldstone bosons and anyonic statistics between
vortices and quasiparticles. We discuss the general structure of discrete and
continuous higherform symmetries in this theory, which can be used to classify
quantum phases. We describe how to identify the appearance of topological order
in such systems and discuss its relation to a mixed 't Hooft anomaly between
discrete higherform symmetries. We apply this framework to the colorflavor
locked phase of dense QCD, which shows anyonic particlevortex statistics while
no topological order appears. An explicit example of superfluidity with
topological order is discussed.

Gravitino condensate in $N=1$ supergravity coupled to the $N=1$ supersymmetric BornInfeld theory. (arXiv:1904.08586v1 [hepth])
Authors: Ryotaro Ishikawa, Sergei V. Ketov
The $N=1$ supersymmetric BornInfeld theory coupled to $N=1$ supergravity in
four spacetime dimensions is studied in the presence of a cosmological term
with spontaneous supersymmetry breaking. The consistency is achieved by
compensating a negative contribution to the cosmological term from the
BornInfeld theory by a positive contribution originating from the gravitino
condensate. This leads to an identification of the BornInfeld scale with the
supersymmetry breaking scale. The dynamical formation of the gravitino
condensate in supergravity is reconsidered and the induced oneloop effective
potential is derived. Slow roll cosmological inflation with the gravitino
condensate as the inflaton (near the maximum of the effective potential) is
viable against the Planck 2018 data and can lead to the inflationary (Hubble)
scale as high as $10^{12}$ GeV. Uplifting the Minkowski vacuum (after
inflation) to a de Sitter vacuum (dark energy) is possible by the use of the
alternative FayetIliopoulos term. Some major physical consequences of our
scenario to reheating are briefly discussed also.

Phase ambiguity of the measure for continuum Majorana fermions. (arXiv:1904.08600v1 [heplat])
Authors: Maarten Golterman, Yigal Shamir
Integrating over a continuum Majorana fermion formally yields a functional
pfaffian. We show that the phase of this pfaffian is ambiguous, as it depends
on the choice of basis. This ambiguity is naturally resolved within a
nonperturbative lattice definition, allowing us to discuss the relation
between the phase of the lattice pfaffian and the effective $\theta$ angle of
the theory. We also resolve an apparent paradox regarding the induced $\theta$
angle when a theory of $N$ Dirac fermions in a real representation of the gauge
group is reexpressed in terms of $2N$ Majorana fermions. We discuss how all
this is reflected in chiral perturbation theory.

Meanfield potential effects in the cumulants of baryons from central Au+Au collision at $E_{lab}$= 1.23 GeV$/$nucleon. (arXiv:1904.08602v1 [nuclth])
Authors: Yongjia Wang, Yunxiao Ye, QIngfeng Li
The cumulants of baryon multiplicity distribution in relativistic heavyion
collisions (HICs) have attracted considerable attention recently. It has been
conjectured that they may serve as a promising observable to detect the
critical end point in the QCD phase diagram, while the cumulants in HICs at
intermediate energies have not been widely studied to date. How to interpret
the cumulants data at intermediate energies and compare with the data at
relativistic energies is now being actively discussed. Both meamfield
potential and clustering are highly important to HICs at intermediate energies.
In this talk, we discuss these effects on the cumulant ratios of baryon number
distributions in Au+Au collisions at beam energies of 1.23 GeV$/$nucleon which
have been currently performed by the HADES Collaboration at GSI. Within the
newest version of the ultrarelativistic quantum molecular dynamics (UrQMD)
model, calculations with different mean field potentials as well as without
mean field potential are performed. It is found that the mean field potential
enhances fluctuations in the momentum space during the expanding stage,
especially in a small rapidity acceptance window. The enhancement of cumulant
ratios for free protons is suppressed compared with that for all baryons.

Twoparticle angular correlations in heavy ion collisions from a multiphase transport model. (arXiv:1904.08603v1 [nuclth])
Authors: LiuYao Zhang, JinHui Chen, ZiWei Lin, YuGang Ma, Song Zhang
We extend our earlier study on twoparticle angular correlations in $pp$
collisions at low transverse momentum ($p_T$) to $p$Pb, PbPb and AuAu
collisions at RHIC and LHC energies. We mainly use the string melting version
of a multiphase transport model with improved quark coalescence for this study.
We start from the analysis of $\pi^{\pm}$, $K^{\pm}$ and $p$($\bar{p}$) $p_T$
and rapidity distributions at different centralities. We then focus on
twoparticle angular correlations in $p$Pb collisions at
$\mathrm{\sqrt{s_{NN}} = 5.02}$ TeV and PbPb collisions at
$\mathrm{\sqrt{s_{NN}}= 2.76}$ TeV. For $p$Pb collisions, a near side
depression in the angular correlation is observed for low $p_T$ proton pairs
and $\Lambda$ pairs but not for pion pairs or kaon pairs, similar to our
earlier finding for $pp$ collisions at $\mathrm{\sqrt{s}= 7}$ TeV. This is also
the case for very low multiplicity PbPb and AuAu collisions. We also find
that parton interactions and the improved quark coalescence are mainly
responsible for the depression feature in baryon pair angular correlations.
However, no such baryonbaryon anticorrelations are observed in PbPb and
AuAu collisions at higher multiplicities. Therefore our results suggest that
low $p_T$ baryonbaryon angular anticorrelations have a strong multiplicity
dependence.

Emergence of hydrodynamical behavior in expanding quarkgluon plasmas. (arXiv:1904.08677v1 [nuclth])
Authors: JeanPaul Blaizot, Li Yan
We use a set of simple angular moments to solve the Boltzmann equation in the
relaxation time approximation for a boost invariant longitudinally expanding
gluonic plasma. The transition from the free streaming regime at early time to
the hydrodynamic regime at late time is well captured by the first twomoments,
corresponding to the monopole and quadrupole components of the momentum
distribution, or equivalently to the energy density and the difference between
the longitudinal and the transverse pressures. We relate this property to the
existence of fixed points in the infinite hierarchy of equations satisfied by
the moments. These fixed points are already present in the twomoment
truncations and are only moderately affected by the coupling to higher moments.
Collisions contribute to a damping of all the non trivial moments. At late
time, when the hydrodynamic regime is entered, only the monopole and quadrupole
moments are significant and remain strongly coupled, the decay of the
quadrupole moment being delayed by the expansion, causing in turn a delay in
the full isotropization of the system. The twomoment truncation contains
second order viscous hydrodynamics, in its various variants, and third order
hydrodynamics, together with explicit values of the relevant transport
coefficients, can be easily obtained from the threemoment truncation.

$B$hadron fragmentation functions at nexttonexttoleading order from global analysis of $e^+e^$ annihilation data. (arXiv:1904.08718v1 [hepph])
Authors: Maral Salajegheh, S. Mohammad Moosavi Nejad, Hamzeh Khanpour, Bernd A. Kniehl, Maryam Soleymaninia
We present nonperturbative fragmentation functions (FFs) for bottomflavored
($B$) hadrons both at nexttoleading (NLO) and, for the first time, at
nexttonexttoleading order (NNLO) in the $\overline{\mathrm{MS}}$
factorization scheme with five massless quark flavors. They are determined by
fitting all available experimental data of inclusive single $B$hadron
production in $e^+e^$ annihilation, from the ALEPH, DELPHI, and OPAL
Collaborations at CERN LEP1 and the SLD Collaboration at SLAC SLC.
The uncertainties in these FFs as well as in the corresponding observables
are estimated using the Hessian approach.
We perform comparisons with available NLO sets of $B$hadron FFs.
We apply our new FFs to generate theoretical predictions for the energy
distribution of $B$ hadrons produced through the decay of unpolarized or
polarized top quarks, to be measured at the CERN LHC.

Lightmeson leptonic decay rates in lattice QCD+QED. (arXiv:1904.08731v1 [heplat])
Authors: M. Di Carlo, D. Giusti, V. Lubicz, G. Martinelli, C.T. Sachrajda, F. Sanfilippo, S. Simula, N. Tantalo
The leading electromagnetic (e.m.) and strong isospinbreaking corrections to
the $\pi^+ \to \mu^+ \nu[\gamma]$ and $K^+ \to \mu^+ \nu[\gamma]$ leptonic
decay rates are evaluated for the first time on the lattice. The results are
obtained using gauge ensembles produced by the European Twisted Mass
Collaboration with $N_f = 2 + 1 + 1$ dynamical quarks. The relative
leadingorder e.m. and strong isospinbreaking corrections to the decay rates
are 1.53(19) % for $\pi_{\mu 2}$ decays and 0.24(10) % for $K_{\mu 2}$ decays.
Using the experimental values of the $\pi_{\mu 2}$ and $K_{\mu 2}$ decay rates
and updated lattice QCD results for the pion and kaon decay constants in
isosymmetric QCD, we find that the CabibboKobayashiMaskawa matrix element
$\vert V_{us}\vert = 0.22538(38)$, reducing by a factor of about $1.8$ the
corresponding uncertainty in the PDG review. Our calculation of $V_{us}$
allows also an accurate determination of the firstrow CKM unitarity relation
$\vert V_{ud}\vert^2 + \vert V_{us}\vert^2 + \vert V_{ub}\vert^2 =
0.99988(44)$. Theoretical developments in this paper include a detailed
discussion of how QCD can be defined in the full QCD+QED theory and an improved
renormalisation procedure in which the bare lattice operators are renormalised
nonperturbatively into the RI$^\prime$MOM scheme and subsequently matched
pertubatively at $O(\alpha_{em}\alpha_s(M_W))$ into the Wregularisation scheme
appropriate for these calculations.

Resummation of soft and Coulomb corrections for $t\bar{t}h$ production at the LHC. (arXiv:1904.08744v1 [hepph])
Authors: WanLi Ju, Li Lin Yang
In this paper, a combined resummation of soft and Coulomb corrections is
performed for the associated production of the Higgs boson with a top quark
pair at the LHC. We illustrate the similarities and critical differences
between this process and the $t\bar{t}$ production process. We show that up to
the nexttoleading power, the total cross section for $t\bar{t}h$ production
admits a similar factorization formula in the threshold limit as that for
$t\bar{t}$ production. This fact, however, is not expected to hold at higher
powers. Based on the factorization formula, we perform the resummation at the
improved nexttoleading logarithmic accuracy, and match to the nexttoleading
order result. This allows us to give NLL$'$+NLO predictions for the total cross
sections at the LHC. We find that the resummation effects enhance the NLO cross
sections by about 6\%, and significantly reduce the scale dependence of the
theoretical predictions.

Proton decay in flux compactifications. (arXiv:1904.08810v1 [hepph])
Authors: Wilfried Buchmuller, Ketan M. Patel
We study proton decay in a sixdimensional orbifold GUT model with gauge
group $SO(10)\times U(1)_A$. Magnetic $U(1)_A$ flux in the compact dimensions
determines the multiplicity of quarklepton generations, and it also breaks
supersymmetry by giving universal GUT scale masses to scalar quarks and
leptons. The model can successfully account for quark and lepton masses and
mixings. Our analysis of proton decay leads to the conclusion that the proton
lifetime must be close to the current experimental lower bound. Moreover, we
find that the branching ratios for the decay channels $p \rightarrow e^+\pi^0$
and $p\rightarrow \mu^+\pi^0$ are of similar size, in fact the latter one can
even be dominant. This is due to flavour nondiagonal couplings of heavy vector
bosons together with large offdiagonal Higgs couplings, which appears to be a
generic feature of flux compactifications.

Nonlinear flavor development of a twodimensional neutrino gas. (arXiv:1904.08877v1 [hepph])
Authors: Joshua D. Martin, Sajad Abbar, Huaiyu Duan
We present a numerical survey of the nonlinear flavor development of dense
neutrino gases. This study is based on the stationary, twodimensional ($x$ and
$z$), twobeam, monochromatic neutrino line model with a periodic boundary
condition along the $x$ direction. Similar to a previous work, we find that
smallscale flavor structures can develop in a neutrino gas even if the
physical conditions are nearly homogeneous along the $x$ axis initially. The
power diffusion from the largescale to smallscale structures increases with
the neutrino density and helps to establish a semiexponential dependence of
the magnitudes of the Fourier moments on the corresponding wave numbers. The
overall flavor conversion probabilities in the neutrino gases with small
initial sinusoidal perturbations reach certain equilibrium values at large
distances which are mainly determined by the neutrinoantineutrino asymmetry.
Similar phenomena also exist in a neutrino gas with a localized initial
perturbation, albeit only inside an expanding flavor conversion region. Our
work suggests that a statistical treatment may be possible for the collective
flavor oscillations of a dense neutrino gas in a multidimensional environment.

Strong dynamics with matter in multiple representations: SU(4) gauge theory with fundamental and sextet fermions. (arXiv:1904.08885v1 [heplat])
Authors: Guido Cossu, Luigi Del Debbio, Marco Panero, David Preti
We present a nonperturbative lattice study of SU(4) gauge theory with two
flavors of fermions in the fundamental representation and two in the twoindex
antisymmetric representation: a theory closely related to a minimal
partialcompositeness model for physics beyond the Standard Model, that was
proposed by G. Ferretti. We discuss the phase structure of the lattice theory
and report results for various observables of interest, including the masses of
states obtained from different combinations of valence fermions and the
spectrum of the Dirac operator. Finally, we comment on the extension of this
type of studies to other partialcompositeness models (including, in
particular, one that was recently suggested by H. Gertov et al.), which could
admit lighter topquark partners, highlighting some key features of our lattice
simulation algorithm, that make it suitable for such generalizations.

Identifying Higgsinolike neutralino with a keVscale dark matter. (arXiv:1904.08906v1 [hepph])
Authors: Juhi Dutta, Biswarup Mukhopadhyaya, Santosh Kumar Rai
The presence of a Higgsinolike neutralino NLSP and a keV scale gravitino
($\widetilde{G}$) LSP opens up new decay modes of the NLSP, mainly to a
Higgs/$Z$ boson and the LSP. Besides, a keVscale gravitino as a warm dark
matter candidate salvages a relativelylight Higgsinolike NLSP from dark
matter constraints. We focus on the prospects of observing $\geq 1 b$ $+$ $
\ell^+\ell^+\slashed{E}_T$ signal at the LHC. A distinguishing feature of this
scenario is the production of longitudinal $Z$ bosons in neutralino decays,
unlike in the case of gauginolike neutralinos, where the $Z$ is mostly
transverse. The polarisation information of the parent $Z$ boson gets reflected
in the angular distributions of the decay leptons and in some other variables
derived therefrom.

The Polarized TwoLoop Massive Pure Singlet Wilson Coefficient for DeepInelastic Scattering. (arXiv:1904.08911v1 [hepph])
Authors: J. Blümlein, C.G. Raab, K. Schönwald
We calculate the polarized massive twoloop pure singlet Wilson coefficient
contributing to the structure functions $g_1(x,Q^2)$ analytically in the whole
kinematic region. The Wilson coefficient contains Kummerelliptic integrals.
We derive the representation in the asymptotic region $Q^2 \gg m^2$, retaining
power corrections, and in the threshold region. The massless Wilson coefficient
is recalculated. The corresponding twist2 corrections to the structure
function $g_2(x,Q^2)$ are obtained by the WandzuraWilczek relation. Numerical
results are presented.

AxionDilaton Destabilization and the Hubble Tension. (arXiv:1904.08912v1 [astroph.CO])
Authors: Stephon Alexander, Evan McDonough
The discrepancy in measurements of the Hubble constant indicates new physics
in dark energy, dark matter, or both. Drawing inspiration from string theory,
where axions interact with the other moduli fields, including the dilaton, here
we demonstrate that the dynamics of an interacting dilaton and axion naturally
realizes the proposal of Early Dark Energy. In this setup, stabilization of the
the dilaton is in part due to the axion, and in the early universe the dilaton
contributes to dark energy. The combined axiondilaton system is destabilized
when the Hubble constant falls below the mass of the axion, triggering a phase
of fastroll evolution of the dilaton wherein its equation of state is $w=1$,
and the early dark energy redshifts away as $a^{6}$.

Cosmicray transport from AMS02 B/C data: benchmark models and interpretation. (arXiv:1904.08917v1 [astroph.HE])
Authors: Yoann Genolini, Mathieu Boudaud, Pedro Ivo Batista, Sami Caroff, Laurent Derome, Julien Lavalle, Alexandre Marcowith, David Maurin, Vincent Poireau, Vivian Poulin, Sylvie Rosier, Pierre Salati, Pasquale Dario Serpico, Manuela Vecchi
This article aims at establishing new benchmark scenarios for Galactic
cosmicray propagation in the GVTV rigidity range, based on fits to the AMS02
B/C data with the USINE v3.5 propagation code. We employ a new fitting
procedure, cautiously taking into account data systematic error correlations in
different rigidity bins and considering Solar modulation potential and leading
nuclear crosssection as nuisance parameters. We delineate specific low,
intermediate, and highrigidity ranges that can be related to both features in
the data and peculiar microphysics mechanisms resulting in spectral breaks. We
single out a scenario which yields excellent fits to the data and includes all
the presumably relevant complexity, the BIG model. This model has two limiting
regimes: (i) the SLIM model, a minimal diffusiononly setup, and (ii) the
QUAINT model, a convectionreacceleration model where transport is tuned by
nonrelativistic effects. All models lead to robust predictions in the
highenergy regime ($\gtrsim10$GV), i.e. independent of the propagation
scenario: at $1\sigma$, the diffusion slope $\delta$ is $[0.430.53]$, whereas
$K_{10}$, the diffusion coefficient at 10GV, is $[0.260.36]$kpc$^2$Myr$^{1}$;
we confirm the robustness of the highenergy break, with a typical value
$\Delta_h\sim 0.2$. We also find a hint for a similar (reversed) feature at low
rigidity around the B/C peak ($\sim 4$GV) which might be related to some
effective damping scale in the magnetic turbulence.

Observational constraints on the tilted flatXCDM and the untilted nonflat XCDM dynamical dark energy inflation parameterizations. (arXiv:1803.05522v4 [astroph.CO] UPDATED)
Authors: ChanGyung Park, Bharat Ratra
We constrain tilted spatiallyflat and untilted nonflat XCDM dynamical dark
energy inflation parameterizations using Planck 2015 cosmic microwave
background (CMB) anisotropy data and recent baryonic acoustic oscillations
distance measurements, Type Ia supernovae data, Hubble parameter observations,
and growth rate measurements. Inclusion of the four nonCMB data sets results
in a significant strengthening of the evidence for nonflatness in the nonflat
XCDM model from 1.1$\sigma$ for the CMB data alone to 3.4$\sigma$ for the full
data combination. In this untilted nonflat XCDM case the data favor a
spatiallyclosed model in which spatial curvature contributes a little less
than a percent of the current cosmological energy budget; they also mildly
favor dynamical dark energy over a cosmological constant at 1.2$\sigma$. These
data are also better fit by the flatXCDM parameterization than by the standard
$\Lambda$CDM model, but only at 0.3$\sigma$ significance. Current data is
unable to rule out dark energy dynamics. The nonflat XCDM parameterization is
compatible with the Dark Energy Survey limits on the present value of the rms
mass fluctuations amplitude ($\sigma_8$) as a function of the present value of
the nonrelativistic matter density parameter ($\Omega_m$), however it does not
provide as good a fit to the higher multipole CMB temperature anisotropy data
as does the standard tilted flat$\Lambda$CDM model. A number of measured
cosmological parameter values differ significantly when determined using the
tilted flatXCDM and the nonflat XCDM parameterizations, including the baryonic
matter density parameter and the reionization optical depth.

Further study on the textures of neutrino mass matrix for maximal atmospherical mixing angle and Dirac CP phase. (arXiv:1808.06837v2 [hepph] UPDATED)
Authors: ZhiCheng Liu, ChongXing Yue, Zhenhua Zhao
In this paper, we derive in a novel approach the possible textures of
neutrino mass matrix that can lead to maximal atmospherical mixing angle
($\theta^{}_{23} = \pi/4$) and Dirac CP phase ($\delta =  \pi/2$) in two
phenomenologically appealing scenarios: (1) one neutrino mass matrix element
being vanishing (2) one neutrino mass being vanishing. For the obtained
textures, some neutrino mass sum rules which relate the neutrino masses and
mixing parameters will emerge. With the help of these sum rules, the unknown
absolute neutrino mass scale and Majorana CP phases can be determined. Some
discussions about the possible textures of neutrino mass matrix that can lead
to $\theta^{}_{23} = \pi/4$, $\delta =  \pi/2$ and maximal Majorana CP phases
($\rho, \sigma = \pi/4$ or $3\pi/4$) as well as the model realization and
breakings of the obtained textures are also given.

Ballistic Dark Matter oscillates above $\Lambda$CDM. (arXiv:1811.00028v2 [astroph.CO] UPDATED)
Authors: Anirban Das (Tata Inst.), Basudeb Dasgupta (Tata Inst.), Rishi Khatri (Tata Inst.)
Dark matter may have been relativistic and collisional until relatively late
times and become cold and collisionless after a phase transition before the
matterradiation equality of the standard $\Lambda$CDM cosmology. We show that
such a dark matter has large peculiar velocities due to acoustic oscillations
before the phase transition, and evolves ballistically after the phase
transition in the collisionless phase until the initial acoustic velocities are
redshifted away. We show that this Ballistic Dark Matter (BDM) results in new
nontrivial interesting features in the cosmological observables. In
particular, the linear matter power spectrum exhibits acoustic oscillations on
scales smaller than the Hubble scale at the time of phase transition, and for
fast transitions the power at the acoustic peaks in the matter power spectrum
exceeds that in a $\Lambda$CDM cosmology. If BDM only forms a part of the total
dark matter, an odd vs. even acoustic peak asymmetry becomes prominent. We give
an approximate analytical treatment of the linear perturbations in BDM,
explaining these features. We also discuss the possibility to constrain BDM
using cosmic microwave background and large scale structure data.

Models of vacuum energy interacting with cold dark matter: Constraints and comparison. (arXiv:1812.00319v2 [astroph.CO] UPDATED)
Authors: HaiLi Li, Lu Feng, JingFei Zhang, Xin Zhang
In this paper, we investigate the observational constraints on the models of
vacuum energy interacting with cold dark matter. We consider eight typical
interaction forms, i.e., $Q=\beta H_{0}\rho_{\rm{vac}}$, $Q=\beta
H_{0}\rho_{\rm{c}}$, $Q=\beta H_{0}(\rho_{\rm{vac}}+\rho_{\rm c})$, $Q=\beta
H_{0}\frac{\rho_{\rm{vac}}\rho_{c}}{\rho_{\rm{vac}}+\rho_{\rm c}}$, $Q=\beta
H\rho_{\rm{vac}}$, $Q=\beta H\rho_{\rm{c}}$, $Q=\beta
H(\rho_{\rm{vac}}+\rho_{\rm c})$, and $Q=\beta
H\frac{\rho_{\rm{vac}}\rho_{c}}{\rho_{\rm{vac}}+\rho_{\rm c}}$. The
observational data used in this work to constrain these models include the JLA
sample of type Ia supernovae observation, the Planck 2015 distance priors data
of cosmic microwave background anisotropies observation, the baryon acoustic
oscillations data, and the Hubble constant direct measurement. We find that the
current observational data almost equally favor these interacting vacuum energy
models. We also find that for all these I$\Lambda$CDM models the case of
$\beta=0$ is actually well consistent with the current observational data
within 1$\sigma$ range.

De Sitter Swampland Bound in DiracBornInfeld Inflation Model. (arXiv:1812.07670v2 [hepth] UPDATED)
Authors: MinSeok Seo
We study the de Sitter (dS) swampland conjecture in DiracBornInfeld (DBI)
inflation model. We obtain the dS swampland bound for the relativistic regime
using Bousso's entropy bound argument and proper distance. It restricts $m_{\rm
Pl}\nabla V/V$ by some positive constant depending on warping and the field
range. In the specific case of the DBI model driven by the quadratic potential,
the model dependent backreaction argument is interpreted as a natural bound for
slowroll parameter. This shows that quasidS spacetime in the DBI model is a
result of tuning.

Foraging for dark matter in large volume liquid scintillator neutrino detectors with multiscatter events. (arXiv:1812.09325v2 [hepph] UPDATED)
Authors: Joseph Bramante, Benjamin Broerman, Jason Kumar, Rafael F. Lang, Maxim Pospelov, Nirmal Raj
We show that dark matter with a pernucleon scattering cross section $\gtrsim
10^{28}~{\rm cm^2}$ could be discovered by liquid scintillator neutrino
detectors like BOREXINO, SNO+, and JUNO. Due to the large dark matter fluxes
admitted, these detectors could find dark matter with masses up to $10^{21}$
GeV, surpassing the mass sensitivity of current direct detection experiments
(such as XENON1T and PICO) by over two orders of magnitude. We derive the
spinindependent and spindependent cross section sensitivity of these
detectors using existing selection triggers, and propose an improved trigger
program that enhances this sensitivity by two orders of magnitude. We interpret
these sensitivities in terms of three dark matter scenarios: (1) effective
contact operators for scattering, (2) QCDcharged dark matter, and (3) a
recently proposed model of Planckmass baryoncharged dark matter. We calculate
the flux attenuation of dark matter at these detectors due to the earth
overburden, taking into account the earth's density profile and elemental
composition, and nuclear spins.

Hydrodynamics of Fermi arcs: Bulk flow and surface collective modes. (arXiv:1901.00006v2 [condmat.strel] UPDATED)
Authors: E. V. Gorbar, V. A. Miransky, I. A. Shovkovy, P. O. Sukhachov
The hydrodynamic description of the Fermi arc surface states is proposed. In
view of the strong suppression of scattering on impurities, the hydrodynamic
regime for Fermi arc states should be, in principle, plausible. By using the
kinetic theory, the Fermi arc hydrodynamics is derived and the corresponding
effects on the bulk flow and surface collective modes are studied. For the bulk
flow, the key effect of the proposed Fermi arc hydrodynamics is the
modification of the corresponding boundary conditions. In a slab geometry, it
is shown that, depending on the transfer rates between the surface and bulk,
the hydrodynamic flow of the electron fluid inside the slab could be
significantly altered and even enhanced near the surfaces. As to the spectrum
of the surface collective modes, in agreement with earlier studies, it is found
that the Fermi arcs allow for an additional gapless spectrum branch and a
strong anisotropy of the surface plasmon dispersion relations in momentum
space. The gapped modes are characterized by closed elliptic contours of
constant frequency in momentum space.

Effective long distance $q\bar{q} $ potential in holographic RG flows. (arXiv:1902.04279v2 [hepth] UPDATED)
Authors: Jorge CasalderreySolana, Diego Gutiez, Carlos Hoyos
We study the $q\bar{q}$ potential in strongly coupled nonconformal field
theories with a nontrivial renormalization group flow via holography. We focus
on the properties of this potential at an interquark separation $L$ large
compared to the characteristic scale of the field theory. These are determined
by the leading order IR physics plus a series of corrections, sensitive to the
properties of the RGflow. To determine those corrections, we propose a general
method applying holographic Wilsonian renormalization to a dual string. We
apply this method to examine in detail two sets of examples, $3+1$dimensional
theories with an RG flow ending in an IR fixed point; and theories that are
confining in the IR, in particular, the Witten QCD and KlebanovStrassler
models. In both cases, we find corrections with a universal dependence on the
interquark separation. When there is an IR fixed point, that correction decays
as a power $\sim 1/L^4$. We explain that dependence in terms of a doubletrace
deformation in a onedimensional defect theory. For a confining theory, the
decay is exponential $\sim e^{ML}$, with $M$ a scale of the order of the
glueball mass. We interpret this correction using an effective flux tube
description as produced by a background internal mode excitation induced by
sources localized at the endpoints of the flux tube. We discuss how these
results could be confronted with lattice QCD data to test whether the
description of confinement via the gauge/gravity is qualitatively correct.

Constraints on Disconnected Contributions in $\pi\pi$ Scattering. (arXiv:1902.10290v2 [heplat] UPDATED)
Authors: N. Ripunjay Acharya, FengKun Guo, UlfG. Meißner, ChienYeah Seng
The accuracy of the lattice QCD computation of hadronhadron scattering at
low isospin depends critically on the ability to compute correlation functions
with fermionic disconnected Wick contractions. This happens, for instance, in
isospin $I=0$ $\pi\pi$ scattering, which receives contributions from
rectangular and vacuum types of contractions among other easier calculable
ones. Combining L\"{u}scher's formula and partiallyquenched chiral
perturbation theory, we provide precise theory predictions of the discrete
energy levels extracted from specific linear combinations of lattice
correlation functions corresponding to various types of contractions.
Expressions are provided for extracting the unphysical lowenergy constants in
the partiallyquenched chiral perturbation theory from the energy levels for
these contractions. The predictions for the rectangular and vacuum contractions
may serve as solid tests of the accuracy for existing and future lattice
studies of $\pi\pi$ scattering.

Nature of the $Y(4260)$: A lightquark perspective. (arXiv:1902.10957v2 [hepph] UPDATED)
Authors: YunHua Chen, LingYun Dai, FengKun Guo, Bastian Kubis
The $Y(4260)$ has been one of the most puzzling pieces among the socalled
$XYZ$ states. In this paper, we try to gain insights into the structure of the
$Y(4260)$ from the lightquark perspective. We study the dipion invariant mass
spectrum of the $e^+ e^ \to Y(4260) \to J/\psi \pi^+\pi^$ process and the
ratio of the cross sections ${\sigma(e^+e^ \to J/\psi K^+ K^)}/{\sigma(e^+e^
\to J/\psi \pi^+\pi^)}$. In particular, we consider the effects of different
lightquark SU(3) eigenstates inside the $Y(4260)$. The strong pionpion
finalstate interactions as well as the $K\bar{K}$ coupled channel in the
$S$wave are taken into account in a modelindependent way using dispersion
theory. We find that the SU(3) octet state plays a significant role in these
transitions, implying that the $Y(4260)$ contains a large lightquark
component. Our findings suggest that the $Y(4260)$ is neither a hybrid nor a
conventional charmonium state, and they are consistent with the $Y(4260)$
having a sizeable $\bar D D_1$ component which, however, is not completely
dominant.

Spinorial Structure of $O(3)$ and Application to Dark Sector. (arXiv:1903.04439v3 [hepph] UPDATED)
Authors: Masaki Yasuè
An $O(3)$ spinor, $\Phi$, as a doublet denoted by ${\bf 2}_D$ consists of an
$SO(3)$ spinor, $\phi$, and its complex conjugate, $\phi^\ast$, which form
$\Phi=\left(\phi,\phi^\ast\right)^T$ to be identified with a Majorana type
spinor of $O(4)$. The four gamma matrices $\Gamma_\mu$ ($\mu=1\sim 4$) are
given by $\Gamma_i=\text{diag.}\left(\tau_i,\tau^\ast_i\right)$ and
$\Gamma_4=\tau_2\otimes\tau_2$, where $\tau_i$ ($i=1,2,3$) denote the Pauli
matrices. While $\Phi$ is regarded as a scalar, a fermionic $O(3)$ spinor is
constructed out of an $SO(3)$ doublet Dirac spinor and its charge conjugate.
These $O(3)$ spinors serve as candidates of dark matter because they are
restricted to be neutral and cannot carry the standard model quantum numbers.
It is possible to introduce a gauge symmetry based on
$SO(3)\times\boldsymbol{Z}_2$ equivalent to $O(3)$, where the
$\boldsymbol{Z}_2$ parity is described by a $U(1)$ charge giving 1 for a
particle as the $SO(3)$ spinor and $1$ for an antiparticle as its conjugate.
The triplet gauge bosons transform as the axial vector of $O(3)$ and the
singlet one as the pseudoscalar of $O(3)$.

Semileptonic decays $B_c \to (\eta_c,J/\psi) l \bar{\nu}_l $ in the "PQCD + Lattice" approach. (arXiv:1904.07530v2 [hepph] UPDATED)
Authors: XueQing Hu, SuPing Jin, ZhenJun Xiao
In this paper, we studied the semileptonic decays $B_c^ \to (\eta_c, J/\psi)
l ^ \bar{\nu}_l$ by employing the PQCD factorization approach, using the newly
defined distribution amplitudes of the $B_c$ meson and also taking into account
the Lattice NRQCD results about the relevant form factors. We found the
following main results: (a) the PQCD predictions for the branching ratios will
become smaller by about $(1050)\%$ when the Lattice NRQCD results about the
form factors are taken into account in the extrapolation of the relevant form
factors; (b) the PQCD predictions for the ratio $R_{\eta_c, J/\psi}$ and the
longitudinal polarization $P_{\tau}$ are $R_{\eta_c}=0.373^{+0.003}_{0.012} ,
R_{J/\psi}=0.300^{+0.005}_{0.004}$, $P_{\tau}^{ \eta_c} =
0.356^{+0.003}_{0.005}$ and $P_{\tau}^{J/\psi } = 0.557 \pm 0.002$ ; and (c)
after the inclusion of the Lattice NRQCD results the predictions are changed
moderately: $R_{\rm \eta_c}=0.300^{+0.033}_{0.031} $, $ R_{\rm
J/\psi}=0.230^{+0.041}_{0.035}$, $P_{\tau}^{ \eta_c} = 0.345\pm 0.010$ and
$P_{\tau}^{ J/\psi} = 0.427 ^{+0.127}_{0.093}$ The theoretical predictions
for $R_{ J/\psi}$ agree with the measured one within errors, and other
predictions could be tested in the future LHCb experiments.

Geometry of ultraperipheral nuclear collisions. (arXiv:1903.12377v3 [nuclth] CROSS LISTED)
Authors: I.M. Dremin
It is advocated that geometry of the interaction region of two heavy nuclei
colliding at large impact parameters is important for the relative role of
lightbylight scattering and QCDinitiated processes. Exclusive production of
resonances is possible by dense electromagnetic fields in the interior space
between the nuclei. The cross section of these processes is evaluated and some
examples are considered. It is speculated that the exclusive production of
$\rho ^0$mesons by twophoton processes forbidden by the LandauYang rule may
become allowed within strong magnetic fields.

Complementarity of Stacking and Multiplet Constraints on the Blazar Contribution to the Cumulative HighEnergy Neutrino Intensity. (arXiv:1904.06371v2 [astroph.HE] CROSS LISTED)
Authors: Chengchao Yuan, Kohta Murase, Peter Mészáros
We investigate the blazar contribution to the cumulative neutrino intensity
assuming a generic relationship between neutrino and gammaray luminosities,
$\log (L_{\nu})\propto \log(L_{\rm ph})$. Using the gammaray luminosity
functions for blazars including flat spectrum radio quasars (FSRQs) and BL Lac
objects, as well as the FermiLAT detection efficiency, we estimate
contributions from resolved blazars and all blazars. Combining the existing
upper limits from stacking analyses, the cumulative neutrino flux from all
blazars are constrained. We also evaluate effects of the redshift evolution and
the effective local number densities for each class of FSRQs, BL Lacs, and all
blazars, by which we place another type of constraints on the blazar
contribution using the nondetection of highenergy neutrino multiplets. We
demonstrate that these two upper limits are complementary, and the joint
consideration of stacking and multiplet analyses support arguments that blazars
are disfavored as the dominant sources in the 100 TeV neutrino sky.
