Tue·Jul 2, 2019Tuesday·July 2, 2019

1. 01*

   Fixing the number of non-sequential generations within the $SU(2{)}_L\otimes U(1{)}_Y$ gauge group

   Elmer Ramirez Barreto🇵🇪 · David Romero Abad🇵🇪

   In this work we explore the possibility to fix the number of new non-sequential chiral-type generations of fermions that could be added to the standard model by combining the condition that arise from the anomalies cancellation with the restriction in the number of flavors impose by the QCD asymptotic freedom. We found that the maximum number of new generations is four, and that allows us at the same time, to place limits for the electrical charges of quarks and leptons within an SM-like framework. Our result is compatible with the constraints involving new generations and their contributions to the oblique parameters $S$ and $T$.

   hep-phhep-thMod.Phys.Lett.A(2019)·0 citations
2. 02*

   Parity-odd Parton Distribution Functions from $\theta$-Vacuum

   Weihua Yang🇨🇳

   Quantum chromodynamics is a fundamental non-abelian gauge theory of strong interactions. The physical quantum chromodynamics vacuum state, $|\theta ⟩$, is a linear superposition of the $n$-vacua states with different topological numbers. Because of the configuration of the gauge fields, the tunneling events can induce the local parity-odd domains. Those interactions that occur in these domains can be affected by these effects. Considering the hadron (nucleon) system, we introduce the parity-odd parton distribution functions in order to describe the parity-odd structures inside the hadron in this paper. We obtain 8 parity-odd parton distribution functions at leading twist for spin-1/2 hadrons and present properties of these parton distribution functions. By introducing the parity-odd quark-quark correlator, we find the parity-odd effects vanish from the macroscopic point of view. Since the parity-odd effects are confined in small domains, we consider the high energy semi-inclusive deeply inelastic scattering process to investigate these effects by calculating the single spin asymmetries.

   hep-phInt.J.Mod.Phys.A(2019)·4 citations
3. 03*

   Cosmological Unification, Dark Energy and the Origin of Neutrino Mass

   J.G. Salazar-Arias🇲🇽 · Abdel Pérez-Lorenzana🇲🇽

   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.

   hep-phPRD(2020)·5 citations
4. 04*

   HE Stratosphere Event of 1975 Revisited: the Difference between the Patterns of Astroparticle Interaction and LHC Nucleus-Nucleus Collision

   Olga I. Piskounova🇷🇺 · Konstantine A. Kotelnikov🇷🇺

   The event of astroparticle collision at high energy was detected in 1975 during the balloon flight in the stratosphere. The data of hundred particle tracks in x-ray films have been re-analyzed in the style of LHC experiments: rapidity distributions of charged particles and transverse mass spectra of multi-particle production have been built. The comparison of multiple histograms with the expectations of the Quark-Gluon String Model (QGSM) gives us, at first sight, the conclusion that it might be the carbon-nucleus collision with the matter of atmosphere at the c.m.s. equivalent energy $\sqrt{s}\ge$ 5 TeV. Nevertheless, the data indicate the features that cannot be associated with nucleus-nucleus collision: one particle with transverse mass 16 GeV was detected and a small nucleon population has been seen in the region of projectile fragmentation that does not correspond to the carbon nucleus collision. Both facts make us convinced that there might be a baryonic DM decay (Piskounova O., 2018). Baryonic DM particles are to be formed at the huge gravitation pressure in giant massive objects like Black Holes. Relativistic jets are spreading the baryonic DM in space. The important difference between this form of matter and the ordinary nucleus lies in the results of collision: baryonic DM is the object, where protons and antiprotons are strongly connected, so the energy is divided between nucleon components due to the structure function of Regge type, like for quarks in the proton. The lightest debris of baryonic DM particle interacts with the greatest maximal rapidity and gives the small number of nucleons in the forwarding part of spectra. Baryonic DM can also split into the pair of similar DM with lower mass giving an unusual couple of hadrons with mass like 14 GeV and heavier.

   hep-phhep-exPoS(2022)·2 citations
5. 05*

   A generalized Higgs potential with two degenerate minima for a dark QCD matter scenario

   Matthias F.M. Lutz🇩🇪 · Yonggoo Heo🇹🇭 · Xiao-Yu Guo🇩🇪

   We consider the Higgs potential in generalizations of the Standard Model. The possibility of the potential to develop two almost degenerate minima is explored. This would imply that QCD matter at two distinct sets of quark masses is relevant for astrophysics and cosmology. If in the exotic minimum the QCD matter ground state is electromagnetically neutral, dark matter may consist of QCD matter and antimatter in bubbles of the Higgs field. We predict an abundance of gamma rays in the few MeV region as messengers of dark matter regions in space. In addition the ratio of dark matter to normal matter is expected to show a time dependence.

   hep-phastro-ph.GAEPJC(2020)·3 citations
6. 06*

   Analysis of the $X(3842)$ as a D-wave charmonium meson

   Guo Liang Yu🇨🇳 · Zhi Gang Wang🇨🇳

   In this article, we assign the newly reported state $X(3842)$ to be a D-wave $\overline{c}c$ meson, and study its mass and decay constant with the QCD sum rules by considering the contributions of the vacuum condensates up to dimension-6 in the operator product expansion. The predicted mass $M_{X(3842)}=(3.844_{-0.0823}^{+0.0675}\pm 0.020)GeV$ is in agreement well with the experimental data $M_{X(3842)}=(3842.71\pm 0.16\pm 0.12)MeV$ from the LHCb collaboration. This result supports assigning $X(3842)$ to be a $1^3{D}_3$ charmonium meson. As the $1^3{D}_3$ $\overline{c}c$ meson, its predicted strong decay width with the ${}^3{P}_0$ decay model is compatible with the experimental data.

   hep-phInt.J.Mod.Phys.A(2019)·10 citations
7. 07*

   Heavy ion anisotropies: a closer look at the angular power spectrum

   Meera Machado🇩🇰

   Anisotropies in the final state of heavy-ion collisions carry information on the creation, expansion and evolution of the quark-gluon plasma. Currently, there is an abundance of studies on azimuthal anisotropies in comparison to longitudinal ones. The purpose of this work is to quantify angular $(\theta ,\varphi )$ correlations to further the understanding of the full spatial 3-D picture of emitted hadrons. Therefore, public ALICE data from Run 1 (2010) of Pb-Pb collisions at $\sqrt{s_{NN}}=2.76\mathrm{TeV}$ is analyzed through the estimation of an angular power spectrum. Issues with $|\eta |<0.9$ limitation are tackled, as well as event multiplicity and detector efficiency. Firstly, spectra are calculated for toy Monte Carlo samples. Secondly, heavy-ion data spectra are presented for the full momentum phase space $0.15<p_T<100\mathrm{GeV}$ and also separate intervals $p_T<0.54\mathrm{GeV}$ and $p_T>0.54\mathrm{GeV}$. The latter reveal how different geometries dominate at distinct scales and transverse momentum. Finally, the study submits particles generated through the AMPT model to the same power spectrum analysis. This comparison shows that in scales dominated by flow geometry, AMPT qualitatively describes the data spectra, while the opposite is true for smaller scales.

   hep-ph1 citation
8. 08*

   Combined explanation of the B-anomalies

   Jacky Kumar🇨🇦

   There are four models of tree-level new physics (NP) that can potentially explain the $b\to s{\mu }^{+}{\mu }^{-}$ and $b\to c\ell \bar{\nu }$ anomalies simultaneously. They are the S3, U3, and U1 leptoquarks and a standard-model-like triplet vector boson (VB). In this talk, I describe an analysis of these models with general couplings. We find that even in this most general case S3 and U3 are excluded. For the U1 model, I discuss the importance of the constraints from lepton-flavor-violating(LFV) processes. As for the VB model, it is shown to be excluded by the additional tree level constraints and LHC bounds on high-mass resonant dimuon pairs. This conclusion is reached without any assumptions about the NP couplings.

   hep-ph0 citations
9. 09*

   Mixing dynamics of dimension-five interactions (scalar/pseudoscalar-photon) in magnetized medium

   Ankur Chaubey🇮🇳 · Manoj K. Jaiswal🇮🇳 · Avijit K. Ganguly🇮🇳

   In many extentions of standard model, dimension-5 scalar di-photon ($g_{\gamma \gamma \varphi }\varphi$ $F^{\mu \nu }{F}_{\mu \nu }$ ) or pseudoscalar di-photon ($g_{\gamma \gamma a}a{\tilde{F}}^{\mu \nu }{F}_{\mu \nu }$, ) interaction materializes due to scale symmetry breaking or $U_A(1)$ symmetry breaking. In a magnetized vacuum (i.e., in an external background field ${\bar{F}}_{\mu \nu }$) the transverse degrees of freedom of the photons-- for such systems-- can be described in terms of the form factors constructed out of the background field strength tensor (${\bar{F}}_{\mu \nu }$) and the same for dynamical photon ($f^{\mu \nu }$); they happen to be ${\bar{F}}_{\mu \nu }{f}^{\mu \nu }$ and ${\widetilde{\stackrel{ˉ}{F}}}_{\mu \nu }{f}^{\mu \nu }$. These form factors transform differently under CP transformation. While ${\bar{F}}_{\mu \nu }{f}^{\mu \nu }$ (describing polarization orthogonal to B ($|{\gamma }_{||}>$)) is CP even, the other one, ${\widetilde{\stackrel{ˉ}{F}}}_{\mu \nu }{f}^{\mu \nu }$( describing polarization along B ($|{\gamma }_{\perp }>$), is CP odd. In the interaction Lagrangian, if the scalar is interchanged with the pseudoscalar, the role of the two form factors just gets interchanged. Thus for nearly degenerate strengths of the coupling constants ( $g_{\gamma \gamma \varphi }$ and $g_{\gamma {\gamma }_a}$ ) and masses ($m_{\varphi }$ and $m_a$ ) of the respective candidates, proper identification of one from the other may become very difficult in laboratory or astrophysics based experiments. The basic motivation of this investigation is to reduce this uncertainty through incorporation of parity violating ({\it originating through magnetized medium effects }) part of the photon self-energy in the effective Lagrangian. This step, in turn affects the (Pseudo) Scalar Photon mixing dynamics drastically and brings out a significant change in the spectrum of the electromagnetic beam undergoing such interaction.

   hep-phSpringer Proc.Phys.(2021)·0 citations
10. 10*

    On trilinear terms in the scalar potential of 3-3-1 gauge models

    Adrian Palcu🇷🇴

    The trilinear terms {\normalsize of the form $\sqrt{2}f{ϵ}^{ijk}{\rho }_i{\chi }_j{\varphi }_k$} in the scalar potential of a 3-3-1 gauge model are considered. When looking for the eigenbasis of the massive physical Higgs bosons that survive the spontaneous symmetry breakdown of the model -- in light of the observed SM-like Higgs boson with mass $m_h\simeq 125$ GeV reported in 2012 at the LHC -- one gets a strong constraint to the cubic term. It has to be smaller than usual $f\ll w$, in flagrant contradiction with the large one $f\simeq w$ which is propagated in the literature to date.

    hep-phMod.Phys.Lett.A(2020)·10 citations
11. 11*

    Properties of oscillons in hilltop potentials: energies, shapes, and lifetimes

    Stefan Antusch🇨🇭 · Francesco Cefala🇨🇭 · Francisco Torrenti🇨🇭

    Oscillons are spatially localised strong fluctuations of a scalar field. They can e.g. form after inflation when the scalar field potential is shallower than quadratic away from the minimum. Although oscillons are not protected by topology, they can be remarkably stable and have a significant impact on the (p)reheating phase. In this work we investigate the properties of oscillons in hilltop-shaped potentials, in particular the typical energies, shapes and lifetimes. In the first part of the paper, we simulate oscillon creation and stabilization with (3+1)-dimensional classical lattice simulations, and extract the typical energies, radii and amplitudes of the oscillons. In the second part we approximate the oscillons as spherically symmetric, and simulate single oscillons until their decay. We find that typical oscillons live up to about 4-5 e-folds, with the individual lifetime of the oscillons depending mainly on the initial shape of the oscillon and the power-law coefficient characterising the particular hilltop model. We also observe a breathing mode in the oscillon radii and amplitudes, and find that stronger breathing implies shorter lifetimes.

    hep-phastro-ph.COhep-thJCAP(2019)·34 citations
12. 12*

    High-energy atmospheric muon flux calculations in comparison with recent measurements

    A. A. Kochanov (1,2)🇷🇺 · A.D. Morozova (3,4)🇷🇺 · T.S. Sinegovskaya (5)🇷🇺 · S.I. Sinegovsky (2,4) ((1) Institute of Solar-Terrestrial Physics SB RAS, (2) Irkutsk State University, (3) Lomonosov Moscow State University, (4) Joint Institute for Nuclear Research, (5) Irkutsk State Transport University)🇷🇺

    Recently the atmospheric muon spectra at high energies were reconstructed for two ranges of zenith angles, basing on the events collected with the IceCube detector. These measurements reach high energies at which the contribution to atmospheric muon fluxes from decays of short-lived hadrons is expected. Latest IceCube measurements of the high-energy atmospheric muon spectrum indicate the presence of prompt muon component at energies above 500 TeV. In this work, the atmospheric conventional muon flux in the energy range 10 GeV - 10 PeV is calculated using a set of hadronic models in combination with known parameterizations of the cosmic ray spectrum by Zatsepin $\&$ Sokolskaya and by Hillas $\&$ Gaisser. The calculation of the prompt muons with use of the quark-gluon string model (QGSM) reproduces the muon data of the IceCube experiment. Nevertheless, an additional contribution to the prompt muon component is required to describe the IceCube muon spectra in case if a charm production model predicts the appreciably lower prompt lepton flux as compared with QGSM. This addition, apparently originating from rare decay modes of the short-lived unflavored mesons $\eta ,{\eta }^{\prime },\rho ,\omega ,\varphi$, might ensure the competing contribution to the high-energy atmospheric muon flux.

    hep-phastro-ph.HEJ.Phys.Conf.Ser.(2019)·9 citations
13. 13*

    Is the observed 125 GeV Higgs boson expected to be SM-like in the NMSSM?

    Conny Beskidt (1)🇩🇪 · Wim de Boer (1) ((1) Dept. of Phys., Karlsruhe Inst. for Technology KIT, Karlsruhe, Germany)🇩🇪

    In the Next-to Minimal Supersymmetric Standard Model (NMSSM) deviations from the SM signal strengths of the 125 GeV Higgs boson are expected, because of the mixing with the additional singlet-like Higgs boson and/or additional decays into pairs of light particles, like neutralinos, pseudo-scalar Higgs bosons or singlet Higgs bosons. In this paper the size of the possible deviations and their expected correlations or anti-correlations between \textit{bosonic} and \textit{fermionic} final states are analyzed using the efficient parameter scanning technique with complete coverage presented in a companion paper. The regions of parameter space with correlated or anti-correlated deviations of the signal strengths are identified.

    hep-ph0 citations
14. 14*

    Fluid Dynamics Study of the $\Lambda$ Polarization for Au+Au Collisions at $\sqrt{s_{NN}}=200$ GeV

    Yilong Xie🇨🇳 · Dujuan Wang🇨🇳 · Laszlo Pal Csernai🇳🇴

    With a Yang-Mills field, stratified shear flow initial state and a high resolution (3+1)D Particle-in-Cell Relativistic (PICR) hydrodynamic model, we calculate the $\Lambda$ polarization for peripheral Au+Au collisions at RHIC energy of $\sqrt{S_{NN}}=200$ GeV. The obtained longitudinal polarization in our model agrees with the experimental signature and the quadrupole structure on transverse momentum plane. It is found that the relativistic correction (2nd term), arising from expansion and from the time component of the thermal vorticity, plays a crucial role in our results. This term is changing the signature and exceeds the first term, arising from the classical vorticity. Finally, the global polarization in our model shows no significant dependence on rapidity, which agrees with the experimental data. It is also found that the second term flattens the sharp peak arising from the classical vorticity (1st term).

    hep-phnucl-thEPJC(2020)·43 citations
15. 15*

    Quasi-Dirac neutrino oscillations at DUNE and JUNO

    G. Anamiati🇪🇸 · V. De Romeri🇪🇸 · M. Hirsch🇪🇸 · C. A. Ternes🇪🇸 · M. Tórtola🇪🇸

    Quasi-Dirac 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 quasi-Dirac particles.

    hep-phhep-exPRD(2019)·29 citations
16. 16*

    Quasi-Conformal Models and the Early Universe

    Alberto Salvio🇮🇹

    Extensions of the Standard Model and general relativity featuring a UV fixed point can leave observable implications at accessible energies. Although mass parameters such as the Planck scale can appear through dimensional transmutation, all fundamental dimension-4 operators can (at least approximately) respect Weyl invariance at finite energy. An example is the Weyl-squared term, whose consistency and observational consequences are studied. This quasi-conformal scenario emerges from the UV complete quadratic gravity and is a possible framework for inflation. We find two realizations. In the first one the inflaton is a fundamental scalar with a quasi-conformal non-minimal coupling to the Ricci scalar. In this case the field excursion must not exceed the Planck mass by far. An example discussed in detail is hilltop inflation. In the second realization the inflaton is a pseudo-Goldstone boson (natural inflation). In this case we show how to obtain an elegant UV completion within an asymptotically free QCD-like theory, in which the inflaton is a composite scalar due to new strong dynamics. We also show how efficient reheating can occur. Unlike the natural inflation based on Einstein gravity, the tensor-to-scalar ratio is well below the current bound set by Planck. In both realizations mentioned above, the basic inflationary formulae are computed analytically and, therefore, these possibilities can be used as simple benchmark models.

    hep-phastro-ph.COgr-qchep-thEPJC(2019)·68 citations
17. 17*

    Inflaxion Dark Matter

    Takeshi Kobayashi🇮🇹 · Lorenzo Ubaldi🇮🇹

    A new mechanism for producing axion dark matter is proposed. By invoking low-scale inflation and a kinetic mixing between the axion and the inflaton, it is shown that the axion is driven to a field point slightly displaced from the potential minimum, which can give rise to the observed dark matter abundance. In this framework, different combinations of the axion and inflaton fields play various cosmological roles, including generating the cosmological perturbations, reheating the universe, and serving as dark matter. The kinetic mixing also relates the dark matter lifetime with the reheating temperature. The mechanism tames axions that would otherwise overdominate the universe, and thus opens up new windows in the axion parameter space, including decay constants at the GUT scale and higher.

    hep-phastro-ph.COhep-thJHEP(2019)·16 citations
18. 18*

    PDFSense: Mapping the PDF sensitivity of future facilities (HL-LHC, LHeC, and EIC)

    T. J. Hobbs🇺🇸 · Bo-Ting Wang🇺🇸 · Pavel M. Nadolsky🇺🇸 · Fredrick I. Olness🇺🇸

    Particle and nuclear physics are moving toward a new generation of experiments to stress-test the Standard Model (SM), search for novel degrees of freedom, and comprehensively map the internal structure of hadrons. Due to the complex nature of QCD and wide array of past, present, and possible future experiments, measurements taken at these next-generation facilities will inhabit an expansive space of high-energy data. Maximizing the impact of each future collider program will depend on identifying its place within this sprawling landscape. As an initial exploration, we use the recently-developed PDFSense framework to assess the PDF sensitivity of two future high-energy facilities --- the high-luminosity upgrade to the LHC (HL-LHC) and the Large Hadron-electron Collider (LHeC) proposal --- as well as the electron-ion collider (EIC) proposed to map the few-GeV quark-hadron transition region. We report that each of these experimental facilities occupies a unique place in the kinematical parameter space with specialized pulls on particular collinear quantities. As such, there is a clear complementarity among these programs, with an opportunity for each to mutually reinforce and inform the others.

    hep-phhep-exnucl-thPoS(2019)·6 citations
19. 19*

    Neutrino Non-Standard Interactions: A Status Report

    P. S. Bhupal Dev🇺🇸 · K. S. Babu🇺🇸 · Peter B. Denton🇺🇸 · Pedro A. N. Machado🇺🇸 · Carlos A. Argüelles🇺🇸 · Joshua L. Barrow🇺🇸 · Sabya Sachi Chatterjee🇬🇧 · Mu-Chun Chen🇺🇸 · André de Gouvêa🇺🇸 · Bhaskar Dutta🇺🇸 · Dorival Gonçalves🇺🇸 · Tao Han🇺🇸 and 14 other authors

    This report summarizes the present status of neutrino non-standard interactions (NSI). After a brief overview, several aspects of NSIs are discussed, including connection to neutrino mass models, model-building and phenomenology of large NSI with both light and heavy mediators, NSI phenomenology in both short- and long-baseline neutrino oscillation experiments, neutrino cross-sections, complementarity of NSI with other low- and high-energy 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 29-31, 2019 (https://indico.cern.ch/event/812851/)

    hep-phastro-ph.COastro-ph.HEhep-ex+1SciPost Phys.Proc.(2019)·265 citations
20. 20*

    Dynamical Emergence of Scalaron in Higgs Inflation

    Yohei Ema🇩🇪

    We point out that a light scalaron dynamically emerges if scalar fields have a sizable non-minimal coupling to the Ricci scalar as in the Higgs inflation model. We support this claim in two ways. One is based on the renormalization group equation; the non-minimal coupling inevitably induces a Ricci scalar quadratic term due to the renormalization group running. The other is based on scattering amplitudes; a scalar four-point amplitude develops a pole after summing over a certain class of diagrams, which we identify as the scalaron. Our result implies that the Higgs inflation is actually a two-field inflationary model. Another implication is that the Higgs inflation does not suffer from the unitarity issue since the scalaron pushes up the cut-off scale to the Planck scale.

    hep-phastro-ph.COgr-qchep-thJCAP(2019)·50 citations
21. 21*

    Confinement in Nuclei and the Expanding Proton

    Gerald A. Miller🇺🇸

    High-precision knowledge of electromagnetic form factors of nuclei is a subject of much current experimental and theoretical activity in nuclear and atomic physics. Such precision mandates that effects of the non-zero spatial extent of the constituent nucleons be handled in a manner that goes beyond the usual impulse approximation. A series of simple, Poincare-invariant, composite-proton models that respect the Ward-Takahashi identity and in which quarks are confined are used to study the validity of this approximation. The result of all of the models is a general theorem showing that medium modification of proton structure must occur. Combining this result with lattice QCD calculations leads to a conclusion that a bound proton must be larger than a free one.

    ↳ nucl-thhep-phnucl-exPRL(2019)·14 citations
22. 22*

    Pulsating white dwarfs: new insights

    Alejandro H. Córsico🇦🇷 · Leandro G. Althaus🇦🇷 · Marcelo M. Miller Bertolami (Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Argentina - Instituto de Astrofıísica La Plata, IALP, CONICET-UNLP)🇦🇷 · S. O. Kepler (Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, Brazil)🇧🇷

    White dwarf stars constitute the final evolutionary stage for more than 95 per cent of all stars. The Galactic population of white dwarfs conveys a wealth of information about several fundamental issues and are of vital importance to study the structure, evolution and chemical enrichment of our Galaxy and its components ---including the star formation history of the Milky Way. In addition, white dwarfs are tracers of the evolution of planetary systems along several phases of stellar evolution. Also, white dwarfs are used as laboratories for astro-particle physics, being their interest focused on physics beyond the standard model. The last decade has witnessed a great progress in the study of white dwarfs. In particular, a wealth of information of these stars from different surveys has allowed us to make meaningful comparison of evolutionary models with observations. While some information like surface chemical composition, temperature and gravity of isolated white dwarfs can be inferred from spectroscopy, and the total mass and radius can be derived as well when they are in binaries, the internal structure of these compact stars can be unveiled only by means of asteroseismology, an approach based on the comparison between the observed pulsation periods of variable stars and the periods predicted by appropriate theoretical models. The asteroseismological techniques allow us to infer details of the internal chemical stratification, the total mass, and even the stellar rotation profile. In this review, we first revise the evolutionary channels currently accepted that lead to the formation of white-dwarf stars, and then, we give a detailed account of the different sub-types of pulsating white dwarfs known so far, emphasizing the recent observational and theoretical advancements in the study of these fascinating variable stars.

    ↳ astro-ph.SRhep-phAstron.Astrophys.Rev.(2019)·89 citations
23. 23*

    CPT- and Lorentz-Violation Tests with Muon g-2

    B. Quinn🇺🇸

    The status of Lorentz- and CPT-violation searches using measurements of the anomalous magnetic moment of the muon is reviewed. Results from muon g-2 experiments have set the majority of the most stringent limits on Standard- Model Extension Lorentz and CPT violation in the muon sector. These limits are consistent with calculations of the level of Standard-Model Extension effects required to account for the current 3.7{\sigma} experiment-theory discrepancy in the muon's g-2. The prospects for the new Muon g-2 Experiment at Fermilab to improve upon these searches is presented.

    ↳ hep-exhep-ph10 citations
24. 24*

    Forecast for weighing neutrinos in cosmology with SKA

    Jing-Fei Zhang🇨🇳 · Bo Wang🇨🇳 · Xin Zhang🇨🇳

    We investigate what role the SKA neutral hydrogen (HI) intensity mapping (IM) sky survey observation will play in weighing neutrinos in cosmology. We use the simulated data of the baryon acoustic oscillation (BAO) measurements from the HI IM survey based on SKA1 and SKA2 to do the analysis. For the current observations, we use the Planck 2015 cosmic microwave background (CMB) anisotropies observation, the optical 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 ${\Omega }_{\mathrm{m}}$ and $H_0$. Compared to the current observation, the SKA1 data can improve the constraints on ${\Omega }_{\mathrm{m}}$ by about 33%, and on $H_0$ by about 36%; the SKA2 data can improve the constraints on ${\Omega }_{\mathrm{m}}$ 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.

    ↳ astro-ph.COgr-qchep-phSCPMA(2020)·36 citations
25. 25*

    Radiative leptonic decays on the lattice

    Christopher Kane🇺🇸 · Christoph Lehner🇺🇸 · Stefan Meinel🇺🇸 · Amarjit Soni🇺🇸

    Adding a hard photon to the final state of a leptonic pseudoscalar-meson decay lifts the helicity suppression and can provide sensitivity to a larger set of operators in the weak effective Hamiltonian. Furthermore, radiative leptonic $B$ decays at high photon energy are well suited to constrain the first inverse moment of the $B$-meson light-cone distribution amplitude, an important parameter in the theory of nonleptonic $B$ decays. We demonstrate that the calculation of radiative leptonic decays is possible using Euclidean lattice QCD, and present preliminary numerical results for $D_s^{+}\to {\ell }^{+}\nu \gamma$ and $K^{-}\to {\ell }^{-}\bar{\nu }\gamma$.

    ↳ hep-lathep-phPoS(2019)·33 citations
26. 26*

    Analysis of the duration$-$hardness ratio plane of gamma-ray bursts with skewed distributions

    Mariusz Tarnopolski🇵🇱

    It was recently shown that the $T_{90}-H_{32}$ distributions of gamma-ray bursts from CGRO/BATSE and Fermi/GBM are well described by a mixture of only two skewed components, making the presumed third, intermediate class unnecesary. The Swift/BAT, Konus-Wind, RHESSI and Suzaku/WAM data sets are found to be consistent with a two-class description as well.

    ↳ astro-ph.HEhep-phMem.Soc.Ast.It.(2019)·6 citations
27. 27*

    Multiple polylogarithms with algebraic arguments and the two-loop EW-QCD Drell-Yan master integrals

    Matthias Heller🇩🇪 · Andreas von Manteuffel🇺🇸 · Robert M. Schabinger🇺🇸

    We consider Feynman integrals with algebraic leading singularities and total differentials in $ϵ\mathrm{d}\ln$ form. We show for the first time that it is possible to evaluate integrals with singularities involving unrationalizable roots in terms of conventional multiple polylogarithms, by either parametric integration or matching the symbol. As our main application, we evaluate the two-loop master integrals relevant to the $\alpha {\alpha }_s$ corrections to Drell-Yan lepton pair production at hadron colliders. We optimize our functional basis to allow for fast and stable numerical evaluations in the physical region of phase space.

    ↳ hep-thhep-phPRD(2020)·108 citations
28. 28*

    Feynman integrals as A-hypergeometric functions

    Leonardo de la Cruz🇬🇧

    We show that the Lee-Pomeransky parametric representation of Feynman integrals can be understood as a solution of a certain Gel'fand-Kapranov-Zelevinsky (GKZ) system. In order to define such GKZ system, we consider the polynomial obtained from the Symanzik polynomials $g=\mathcal{U}+\mathcal{F}$ as having indeterminate coefficients. Noncompact integration cycles can be determined from the coamoeba---the argument mapping---of the algebraic variety associated with $g$. In general, we add a deformation to $g$ in order to define integrals of generic graphs as linear combinations of their canonical series. We evaluate several Feynman integrals with arbitrary non-integer powers in the propagators using the canonical series algorithm.

    ↳ math-phhep-phhep-thmath.MPJHEP(2019)·96 citations
29. 29*

    Hypercharge Quantisation and Fermat's Last Theorem

    Nakarin Lohitsiri🇬🇧 · David Tong🇬🇧

    What values of the Standard Model hypercharges result in a mathematically consistent quantum field theory? We show that the constraints imposed by the lack of gauge anomalies can be recast as the equation x^3 + y^3 = z^3. If hypercharge is quantised, then x, y and z must be integers. The trivial (and only) solutions, with x=0 or y=0, reproduce the hypercharge assignments seen in Nature. This argument does not rely on the mixed gauge-gravitational anomaly, which is automatically vanishing if hypercharge is quantised and the gauge anomalies vanish.

    ↳ hep-thhep-phSciPost Phys.(2020)·14 citations
30. 30*

    On a first order transition in QCD with up, down and strange quarks

    Xiao-Yu Guo🇩🇪 · Yonggoo Heo🇹🇭 · Matthias F.M. Lutz🇩🇪

    We consider the quark-mass dependence of the baryon octet and decuplet ground state masses. It is predicted that QCD dynamics implies a first order transition when increasing the strange quark mass from its chiral limit towards its physical value. Our claim relies on a global fit to the available QCD lattice data on such baryon masses. Quantitative results based on an application of the chiral SU(3) Lagrangian at N${}^3$LO are discussed. We predict an anomalous sector of QCD where stable baryonic matter would be composed of lambda or anti-lambda particles rather than nucleons and anti-nucleons.

    ↳ hep-lathep-phEPJC(2020)·11 citations
31. 31*

    Reduced-order surrogate models for scalar-tensor gravity in the strong field and applications to binary pulsars and GW170817

    Junjie Zhao🇨🇳 · Lijing Shao🇨🇳 · Zhoujian Cao🇨🇳 · Bo-Qiang Ma🇨🇳

    We investigate the scalar-tensor gravity of Damour and Esposito-Farèse (DEF), which predicts non-trivial phenomena in the nonperturbative strong-field regime for neutron stars (NSs). Instead of solving the modified Tolman-Oppenheimer-Volkoff equations, we construct reduced-order surrogate models, coded in the pySTGROM package, to predict the relations of a NS radius, mass, and effective scalar coupling to its central density. Our models are accurate at $\sim 1\%$ level and speed up large-scale calculations by two orders of magnitude. As an application, we use pySTGROM and Markov-chain Monte Carlo techniques to constrain parameters in the DEF theory, with five well-timed binary pulsars, the binary NS (BNS) inspiral GW170817, and a hypothetical BNS inspiral in the Advanced LIGO and next-generation GW detectors. In the future, as more binary pulsars and BNS mergers are detected, our surrogate models will be helpful in constraining strong-field gravity with essential speed and accuracy.

    ↳ gr-qcastro-ph.HEhep-phPRD(2019)·47 citations
32. 32*

    Hadronic light-by-light contribution to the muon anomalous magnetic moment from lattice QCD

    Thomas Blum · Norman Christ · Masashi Hayakawa · Taku Izubuchi · Luchang Jin · Chulwoo Jung · Christoph Lehner

    We report preliminary results for the hadronic light-by-light scattering contribution to the muon anomalous magnetic moment. Several ensembles using 2+1 flavors of Möbius domain-wall fermions, generated by the RBC/UKQCD collaborations, are employed to take the continuum and infinite volume limits of finite volume lattice QED+QCD. We find $a_{\mu }^{\mathrm{HLbL}}=(7.41\pm 6.33)\times 10^{-10}$

    ↳ hep-lathep-ph1 citation
33. 33*

    Baryon as a Quantum Hall Droplet and the Cheshire Cat Principle

    Yong-Liang Ma🇨🇳 · Maciej A. Nowak🇵🇱 · Mannque Rho🇫🇷 · Ismail Zahed🇺🇸

    We show that the recent proposal to describe the $N_f=1$ baryon in the large number of color limit as a quantum Hall droplet, can be understood as a chiral bag in a 1+2 dimensional strip using the Cheshire cat principle. For a small bag radius, the bag reduces to a vortex line which is the smile of the cat with flowing gapless quarks all spinning in the same direction. The disc enclosed by the smile is described by a topological field theory due to the Callan-Harvey anomaly out-flow. The chiral bag carries naturally unit baryon number and spin $\frac{1}{2}{N}_c$. The generalization to arbitrary $N_f$ is discussed.

    ↳ hep-thhep-phnucl-thPRL(2019)·35 citations
34. 34*

    Constraints on dark matter annihilation in dwarf spheroidal galaxies from low frequency radio observations

    Arpan Kar🇮🇳 · Sourav Mitra🇮🇳 · Biswarup Mukhopadhyaya🇮🇳 · Tirthankar Roy Choudhury🇮🇳 · Steven Tingay🇦🇺

    We present the first observational limits on the predicted synchrotron signals from particle Dark Matter annihilation models in dwarf spheroidal galaxies at radio frequencies below 1 GHz. We use a combination of survey data from the Murchison Widefield Array (MWA) and the Giant Metre-wave Radio Telescope (GMRT) to search for diffuse radio emission from 14 dwarf spheroidal galaxies. For in-situ magnetic fields of 1 $\mu G$ and any plausible value for the diffusion coefficient, our limits do not constrain any Dark Matter models. However, for stronger magnetic fields our data might provide constraints comparable to existing limits from gamma-ray and cosmic ray observations. Predictions for the sensitivity of the upgraded MWA show that models with Dark Matter particle mass up to $\sim$ 1.6 TeV (1 TeV) may be constrained for magnetic field of 2 $\mu G$ (1 $\mu G$). While much deeper limits from the future low frequency Square Kilometre Array (SKA) will challenge the LHC in searches for Dark Matter particles, the MWA provides a valuable first step toward the SKA at low frequencies.

    ↳ astro-ph.HEhep-phPRD(2019)·24 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.