Mon·Nov 11, 2019Monday·November 11, 2019

1. 01*

   Multi-component dark matter from a hidden gauged SU(3)

   Stephen Godfrey🇨🇦 · Alexandre Poulin (Carleton University)🇨🇦

   We studied Dark Matter (DM) phenomenology with multiple DM species consisting of both scalar and vector DM particles in the Hidden Gauged SU(3) model of Arcadi et al. Because of the large parameter space in the Hidden Gauged SU(3) model we restrict ourselves to three representative benchmark points, each with multiple DM species. The relic densities for the benchmark points were found using a program developed to solve the coupled Boltzmann equations for an arbitrary number of interacting DM species with two particles in the final state. For each case, we varied the mass of the DM particles and then found the value of the dark SU(3) gauge coupling that gave the correct relic density. We found that in some regions of parameter space, DM would be difficult to observe in direct detection experiments while it would be easier to observe in indirect detection experiments while for other regions of parameter space the situation was reversed. Thus, measurements from both types of experiments complement each other and could help pinpoint the details of the hidden SU(3) model.

   hep-phPoS(2019)·0 citations
2. 02*

   A new mechanism for matter-antimatter asymmetry and connection with dark matter

   Arnab Dasgupta🇰🇷 · P. S. Bhupal Dev🇺🇸 · Sin Kyu Kang🇰🇷 · Yongchao Zhang🇺🇸

   We propose a new mechanism for generating matter-antimatter asymmetry via the interference of tree-level diagrams only, where the imaginary part of the Breit-Wigner propagator for an unstable mediator plays a crucial role. We first derive a general result that a nonzero $CP$-asymmetry can be generated via at least two sets of interfering tree-level diagrams involving either $2\to 2$ or $1\to n$ (with $n\ge 3$) processes. We illustrate this point in a simple TeV-scale extension of the Standard Model with an inert Higgs doublet and right-handed neutrinos, along with an electroweak-triplet scalar field, where small Majorana neutrino masses are generated via a combination of radiative type-I and tree-level type-II seesaw mechanisms. The imaginary part needed for the required $CP$-asymmetry comes from the trilinear coupling of the inert doublet with the triplet scalar, along with the width of the triplet scalar mediator. The real part of the neutral component of the inert doublet serves as a cold dark matter candidate. The evolutions of the dark matter relic density and the baryon asymmetry are intimately related in this scenario.

   hep-phastro-ph.COhep-exPRD(2020)·31 citations
3. 03*

   Unravelling the anomalous gauge boson couplings in $Z{W}^{\pm }$ production at the LHC and the role of spin-$1$ polarizations

   Rafiqul Rahaman🇮🇳 · Ritesh K. Singh🇮🇳

   We study the anomalous triple gauge boson couplings (aTGC) in $Z{W}^{\pm }$ production in $3l$ + missing $E_T$ channel at the LHC for $\sqrt{s}=13$ TeV. We use cross sections, azimuthal asymmetry, forward-backward asymmetry, and polarization asymmetries of $Z$ and reconstructed $W$ to estimate simultaneous limits on the anomalous couplings for both the effective vertex formalism as well as the effective operator approach using the Markov-chain--Monte-Carlo (MCMC) method for luminosities $35.9$ fb${}^{-1}$, $100$ fb${}^{-1}$, $300$ fb${}^{-1}$, $1000$ fb${}^{-1}$, and $3000$ fb${}^{-1}$. The trilepton invariant mass ($m_{3l}$)and the transverse momentum of $Z$ ($p_T(Z)$) are found to be sensitive to the aTGC for the cross sections as well as for the asymmetries. We observed that the asymmetries significantly improve the measurement of anomalous couplings at the high-luminosity large hadron collider (LHC) if a deviation from the Standard Model (SM) is observed.

   hep-phhep-exhep-latJHEP(2020)·26 citations
4. 04*

   Invisible and displaced dark matter signatures at Belle II

   Michael Duerr🇩🇪 · Torben Ferber🇩🇪 · Christopher Hearty🇨🇦 · Felix Kahlhoefer🇩🇪 · Kai Schmidt-Hoberg🇩🇪 · Patrick Tunney🇩🇪

   Many dark matter models generically predict invisible and displaced signatures at Belle II, but even striking events may be missed by the currently implemented search programme because of inefficient trigger algorithms. Of particular interest are final states with a single photon accompanied by missing energy and a displaced pair of electrons, muons, or hadrons. We argue that a displaced vertex trigger will be essential to achieve optimal sensitivity at Belle II. To illustrate this point, we study a simple but well-motivated model of thermal inelastic dark matter in which this signature naturally occurs and show that otherwise inaccessible regions of parameter space can be tested with such a search. We also evaluate the sensitivity of single-photon searches at BaBar and Belle II to this model and provide detailed calculations of the relic density target.

   hep-phhep-exJHEP(2020)·98 citations
5. 05*

   MeV-GeV $\gamma$-ray telescopes probing axino LSP/gravitino NLSP as dark matter in the $\mu \nu$SSM

   German A. Gomez-Vargas🇨🇱 · Daniel E. Lopez-Fogliani🇦🇷 · Carlos Munoz🇪🇸 · Andres D. Perez🇦🇷

   Axino and gravitino are promising candidates to solve the dark matter (DM) problem in the framework of supersymmetry. In this work, we assume that the axino is the lightest supersymmetric particle (LSP), and therefore contributes to DM. In the case of R-parity violating models, the axino can decay into a neutrino-photon pair with a lifetime much longer than the age of the Universe, yielding a potentially detectable signal. Interestingly, a gravitino next-to-LSP (NLSP) can live enough as to contribute to the relic density. We study both scenarios, only axino LSP as DM, and axino LSP with gravitino NLSP as DM. We carry out the analysis in the context of the $\mu \nu$SSM, which solves the $\mu$ problem and reproduces neutrino data, only adding couplings involving right-handed neutrinos. In particular, we perform a complete analysis of the relevant parameter space of the model considering constraints from neutrino physics, cosmological observations, and $\gamma$-ray detection. We find that the axino or the gravitino can produce a signal detectable by future MeV-GeV $\gamma$-ray telescopes. In addition, in a parameter region where we get a well-tempered mixture of both particles, a double-line signal arises as a smoking gun.

   hep-phastro-ph.HEJCAP(2020)·25 citations
6. 06*

   Distinguishing between the twin $b$-flavored unitarity triangles on a circular arc

   Zhi-zhong Xing🇨🇳 · Di Zhang🇨🇳

   With the help of the generalized Wolfenstein parametrization of quark flavor mixing and CP violation, we calculate fine differences between the twin $b$-flavored unitarity triangles defined by $V_{ub}^{\ast }{V}_{ud}^{}+V_{cb}^{\ast }{V}_{cd}^{}+V_{tb}^{\ast }{V}_{td}^{}=0$ and $V_{ud}^{\ast }{V}_{td}^{}+V_{us}^{\ast }{V}_{ts}^{}+V_{ub}^{\ast }{V}_{tb}^{}=0$ in the complex plane. We find that vertices of the rescaled versions of these two triangles, described respectively by $\bar{\rho }+\mathrm{i}\bar{\eta }=-\left(V_{ub}^{\ast }{V}_{ud}^{}\right)/\left(V_{cb}^{\ast }{V}_{cd}^{}\right)$ and $\tilde{\rho }+\mathrm{i}\tilde{\eta }=-\left(V_{ub}^{\ast }{V}_{tb}^{}\right)/\left(V_{us}^{\ast }{V}_{ts}^{}\right)$, are located on a circular arc whose center and radius are given by $O=\left(0.5,0.5\cot \alpha \right)$ and $R=0.5\csc \alpha$ with $\alpha$ being their common inner angle. The small difference between $(\bar{\rho },\bar{\eta })$ and $(\tilde{\rho },\tilde{\eta })$ is characterized by $\tilde{\rho }-\bar{\rho }\sim \tilde{\eta }-\bar{\eta }\sim \mathcal{O}({\lambda }^2)$ with $\lambda \simeq 0.22$ being the Wolfenstein expansion parameter, and these two vertices are insensitive to the two-loop renormalization-group running effects up to the accuracy of $\mathcal{O}({\lambda }^4)$. Some comments are also made on similar features of three pairs of the rescaled unitarity triangles of lepton flavor mixing and CP violation.

   hep-phhep-exPLB(2020)·10 citations
7. 07*

   Conspiracy of BSM physics and cosmology

   Maxim Yu. Khlopov🇷🇺

   The lack of experimental evidence at the LHC for physics beyond the Standard model (BSM) of elementary particles together with necessity of its existence to provide solutions of internal problems of the Standard model (SM) as well as of physical nature of the basic elements of the modern cosmology demonstrates the conspiracy of BSM physics. Simultaneously the data of precision cosmology only tighten the constraints on the deviations from the now standard LambdaCDM model and thus exhibit conspiracy of the nonstandard cosmological scenarios. We show that studying new physics in combination of its physical, astrophysical and cosmological probes, can not only unveil the conspiracy of BSM physics but will also inevitably reveal nonstandard features in the cosmological scenario.

   hep-phastro-ph.CO3 citations
8. 08*

   The DNNLikelihood: enhancing likelihood distribution with Deep Learning

   Andrea Coccaro🇮🇹 · Maurizio Pierini🇨🇭 · Luca Silvestrini🇮🇹 · Riccardo Torre🇨🇭

   We introduce the DNNLikelihood, a novel framework to easily encode, through Deep Neural Networks (DNN), the full experimental information contained in complicated likelihood functions (LFs). We show how to efficiently parametrise the LF, treated as a multivariate function of parameters and nuisance parameters with high dimensionality, as an interpolating function in the form of a DNN predictor. We do not use any Gaussian approximation or dimensionality reduction, such as marginalisation or profiling over nuisance parameters, so that the full experimental information is retained. The procedure applies to both binned and unbinned LFs, and allows for an efficient distribution to multiple software platforms, e.g. through the framework-independent ONNX model format. The distributed DNNLikelihood can be used for different use cases, such as re-sampling through Markov Chain Monte Carlo techniques, possibly with custom priors, combination with other LFs, when the correlations among parameters are known, and re-interpretation within different statistical approaches, i.e. Bayesian vs frequentist. We discuss the accuracy of our proposal and its relations with other approximation techniques and likelihood distribution frameworks. As an example, we apply our procedure to a pseudo-experiment corresponding to a realistic LHC search for new physics already considered in the literature.

   hep-phastro-ph.COhep-exphysics.data-anEPJC(2020)·30 citations
9. 09*

   Soft leptogenesis in the NMSSM with a singlet right-handed neutrino superfield

   Waleed Abdallah🇮🇳 · Abhass Kumar🇮🇳 · Abhijit Kumar Saha🇮🇳

   In this work, we explore soft leptogenesis in the NMSSM framework extended by a right-handed neutrino superfield. We calculate the CP asymmetry, $\epsilon$, and find it to be non-zero at tree-level without using thermal effects for the final state particles. This is in contrast to soft leptogenesis in the MSSM extended by a right-handed neutrino superfield where thermal effects are essential. The difference arises due to the presence of a 3-body decay of the sneutrino in the NMSSM that violates lepton number at tree-level. Apart from this, we also find that $\epsilon \ne 0$ if the additional singlet scalar has a complex vacuum expectation value while all the other NMSSM parameters including the soft SUSY breaking ones relevant for CP asymmetry remain real. We estimate the order of magnitudes of these parameters to produce sufficient baryon asymmetry of the Universe.

   hep-phJHEP(2020)·5 citations
10. 10*

    Photon production and elliptic flow from momentum-anisotropic quark-gluon plasma

    Babak Salehi Kasmaei🇺🇸 · Michael Strickland🇺🇸

    The emission of real photons from a momentum-anisotropic quark-gluon plasma (QGP) is affected by both the collective flow of the radiating medium and the modification of local rest frame emission rate due to the anisotropic momentum distribution of partonic degrees of freedom. In this paper, we first calculate the photon production rate from an ellipsoidally momentum-anisotropic QGP including hard contributions from Compton scattering and quark pair annihilation and soft contribution calculated using the hard thermal loop (HTL) approximation. We introduce a parametrization of the nonequilibrium rate in order to facilitate its further application in yield and flow calculations. We convolve the anisotropic photon rate with the space-time evolution of QGP provided by 3+1d anisotropic hydrodynamics (aHydro) to obtain the yield and the elliptic flow coefficient $v_2$ of photons from QGP generated at Pb-Pb collisions at LHC at 2.76 TeV and Au-Au collisions at RHIC at 200 GeV. We investigate the effects of various parameters on the results. In particular we analyze the sensitivity of results to initial momentum anisotropy.

    hep-phnucl-thPRD(2020)·35 citations
11. 11*

    Light(ly)-coupled Dark Matter in the keV Range: Freeze-In and Constraints

    Jae Hyeok Chang🇺🇸 · Rouven Essig🇺🇸 · Annika Reinert🇩🇪

    Dark matter produced from thermal freeze-out is typically restricted to have masses above roughly 1 MeV. However, if the couplings are small, the freeze-in mechanism allows for production of dark matter down to keV masses. We consider dark matter coupled to a dark photon that mixes with the photon and dark matter coupled to photons through an electric or magnetic dipole moment. We discuss contributions to the freeze-in production of such dark matter particles from standard model fermion-antifermion annihilation and plasmon decay. We also derive constraints on such dark matter from the cooling of red giant stars and horizontal branch stars, carefully evaluating the thermal processes as well as the bremsstrahlung process that dominates for masses above the plasma frequency. We find that the parameters needed to obtain the observed relic abundance from freeze-in are excluded below a few tens of keV, depending on the value of the dark gauge coupling constant for the dark photon portal model, and below a few keV, depending on the reheating temperature for dark matter with an electric or magnetic dipole moment. While laboratory probes are unlikely to probe these freeze-in scenarios in general, we show that for dark matter with an electric or magnetic dipole moment and for dark matter masses above the reheating temperature, the couplings needed for freeze-in to produce the observed relic abundance can be probed partially by upcoming direct-detection experiments.

    hep-phastro-ph.COJHEP(2021)·78 citations
12. 12*

    Cosmological Dependence of Resonantly Produced Sterile Neutrinos

    Graciela B. Gelmini🇺🇸 · Philip Lu🇺🇸 · Volodymyr Takhistov🇺🇸

    The detection of a sterile neutrino could constitute the first observation of a particle that could have been produced before Big-Bang Nucleosynthesis (BBN), and could provide information about the yet untested pre-BBN era. The cosmological evolution in this era could be drastically different than typically assumed in what constitutes the standard cosmology, as happens in a variety of motivated particle models. In this work we assess the sensitivity to different pre-BBN cosmologies in which entropy is conserved of 0.01 eV to 1 MeV mass sterile neutrinos produced in the early Universe via resonant active-sterile oscillations, which requires a large lepton asymmetry. We identify mass ranges where it is possible to have two populations of the same sterile neutrino, one with a colder and one with a hotter momentum spectra, which is in principle an observable effect. Furthermore, we show the regions in mass and mixing where fully resonant production (i.e. simultaneously coherent and adiabatic) can occur. We find that in several of the cosmologies we consider, including the standard one, for a lepton asymmetry larger than $\sim 10^{-4}$ fully resonantly produced sterile neutrinos in the eV-mass range can evade all cosmological constraints.

    hep-phastro-ph.COhep-exJCAP(2020)·28 citations
13. 13*

    Prompt hadroproduction of ${\eta }_c(1S,2S)$ in the $k_T$-factorization approach

    Izabela Babiarz🇵🇱 · Roman Pasechnik🇸🇪 · Wolfgang Schäfer🇵🇱 · Antoni Szczurek🇵🇱

    In this work, we present a thorough analysis of ${\eta }_c(1S,2S)$ quarkonia hadroproduction in $k_{\perp }$-factorisation in the framework of the light-front potential approach for the quarkonium wave function. The off-shell matrix elements for the $g^{\ast }{g}^{\ast }{\eta }_c(1S,2S)$ vertices are derived. We discuss the importance of taking into account the gluon virtualities. %We discuss the role of relativistic corrections, the Melosh spin-rotation and theoretical uncertainties by comparing our results with the standard NRQCD approach. We present the transverse momentum distributions of ${\eta }_c$ for several models of the unintegrated gluon distributions. Our calculations are performed for four distinct parameterisations for the $c\bar{c}$ interaction potential consistent with the meson spectra. We compare our results for ${\eta }_c(1S)$ to measurements by the LHCb collaboration and present predictions for ${\eta }_c(2S)$ production.

    hep-phJHEP(2020)·32 citations
14. 14*

    Neutrino Mass Matrix Model with Only Three Adjustable Parameters

    Yoshio Koide🇯🇵 · Hiroyuki Nishiura🇯🇵

    Stimulated by a successful quark mass matrix model based on U(3)$\times$U(3)${}^{\prime }$ family symmetry, a phenomenological neutrino mass matrix for the Majorana neutrinos $({\nu }_L,{\nu }_R^c,N_L,N_R^c)$ is proposed. The model has only three adjustable parameters. Nevertheless, the model gives reasonable predictions for the neutrino masses, mixings, and CP violating phases in the neutrino mixing matrix.

    hep-ph0 citations
15. 15*

    Binomial acceptance corrections for particle number distributions in high-energy reactions

    Oleh Savchuk🇺🇦 · Roman V. Poberezhnyuk🇺🇦 · Volodymyr Vovchenko🇩🇪 · Mark I. Gorenstein🇺🇦

    The binomial acceptance correction procedure is studied for particle number distributions detected in high energy reactions in finite regions of the momentum space. We present acceptance correction formulas for scaled variance, skewness, and kurtosis. Our considerations include various specific types of particles - positively or negatively charged, baryons and antibaryons - as well as conserved charges, namely, the net baryon number and electric charge. A simple model with effects of exact charge conservation, namely the Bessel distribution, is studied in some detail where effects of multi-particle correlations are present. The accuracy of the binomial filter is studied with UrQMD model simulations of inelastic proton-proton reactions. Binomial acceptance correction procedure works well when used inside a small region of phase space as well as for certain efficiency corrections, in particular for constructing net proton fluctuation from net baryon ones. Its performance is less accurate when applied to obtain UrQMD fluctuations in a finite rapidity window from fluctuations in the full $4\pi$ space.

    hep-phhep-exnucl-thPRC(2020)·29 citations
16. 16*

    Light sterile neutrinos: the current picture from neutrino oscillations

    S. Gariazzo🇪🇸

    Light sterile neutrinos with a mass around 1 eV have been studied for many years as a possible explanation of the so called short-baseline neutrino oscillation anomalies. Recently, several neutrino oscillation experiments reported preferences for non-zero values of the mixing angles and squared mass differences for active-sterile mixing, which however are not always in agreement. I will review our current knowledge on the light sterile neutrino in the 3+1 model, starting with a separate discussion on the status of the most relevant searches and then analyzing the problems that arise when combining different probes in a global fit.

    hep-phJ.Phys.Conf.Ser.(2020)·1 citation
17. 17*

    Improving Fermion Mass Hierarchy in Grand Gauge-Higgs Unification with Localized Gauge Kinetic Terms

    Nobuhito Maru🇯🇵 · Yoshiki Yatagai🇯🇵

    Grand gauge-Higgs unification of five dimensional SU(6) gauge theory on an orbifold S^1/Z_2 with localized gauge kinetic terms is discussed. The Standard model (SM) fermions on one of the boundaries and some massive bulk fermions coupling to the SM fermions on the boundary are introduced, so that they respect an SU(5) symmetry structure. The SM fermion masses including top quark are reproduced by mild tuning the bulk masses and parameters of the localized gauge kinetic terms. Gauge coupling universality is not guaranteed by the presence of the localized gauge kinetic terms and it severely constrains the Higgs vacuum expectation value. Higgs potential analysis shows that the electroweak symmetry breaking occurs by introducing additional bulk fermions in simplified representations.The localized gauge kinetic terms enhance the magnitude of the compactification scale, which helps Higgs boson mass large. Indeed the observed Higgs boson mass 125 GeV is obtained.

    hep-phEPJC(2020)·19 citations
18. 18*

    Spectral features of non-equilibrium antineutrinos of primordial nucleosynthesis

    Vlad Yu. Yurchenko🇷🇺 · Alexandre V. Ivanchik🇷🇺

    During the era of primordial nucleosynthesis the background of non-equilibrium antineutrinos is being formed due to decays of neutrons and nuclei of tritium. The spectra of antineutrinos of this background were calculated taking into account the Coulomb interaction between electron and daughter nucleus in ${\beta }^{-}$-decay. The dependence of these spectra on the value of the baryon-to-photon ratio $\eta$ at the period of primordial nucleosynthesis is investigated. The observations of these antineutrinos will allow us to look directly at the very early Universe and nonequilibrium processes taken place before, during, and some time after primordial nucleosynthesis. In any case, this phenomenon is one more aspect in the picture of the standard cosmological model.

    hep-phastro-ph.COAstropart.Phys.(2021)·5 citations
19. 19*

    Natural Twin Neutralino Dark Matter

    Marcin Badziak🇵🇱 · Giovanni Grilli di Cortona🇵🇱 · Keisuke Harigaya🇺🇸

    Supersymmetric Twin Higgs models have a discrete symmetry for which each Standard Model particle and its supersymmetric partner have a corresponding state that transforms under a mirror Standard Model gauge group. This framework is able to accommodate the non-discovery of new particles at the LHC with the naturalness of the electroweak scale. We point out that supersymmetric Twin Higgs models also provide a natural dark matter candidate. We investigate the possibility that a twin bino-like state is the Lightest Supersymmetric Particle and find that its freeze-out abundance can explain the observed dark matter abundance without fine-tuning the mass spectrum of the theory. Most of the viable parameter space can be probed by future dark matter direct detection experiments and the LHC searches for staus and higgsinos which may involve displaced vertices.

    hep-phPRL(2020)·27 citations
20. 20*

    Multiphonon excitations from dark matter scattering in crystals

    Brian Campbell-Deem🇺🇸 · Peter Cox🇦🇺 · Simon Knapen🇺🇸 · Tongyan Lin🇺🇸 · Tom Melia🇯🇵

    For direct detection of sub-MeV dark matter, a promising strategy is to search for individual phonon excitations in a crystal. We perform an analytic calculation of the rate for light dark matter (keV $<m_{DM}<$ MeV) to produce two acoustic phonons through scattering in cubic crystals such as GaAs, Ge, Si and diamond. The multiphonon rate is always smaller than the rate to produce a single optical phonon, whenever the latter is kinematically accessible. In Si and diamond there is a dark matter mass range for which multiphonon production can be the most promising process, depending on the experimental threshold.

    hep-phPRD(2020)·56 citations
21. 21*

    Multilepton dark matter signals

    J.A. Aguilar-Saavedra🇪🇸 · J.A. Casas🇪🇸 · J. Quilis🇪🇸 · R. Ruiz de Austri🇪🇸

    The signatures of dark matter at the LHC commonly involve, in simplified scenarios, the production of a single particle plus large missing energy, from the undetected dark matter. However, in $Z^{\prime }$-portal scenarios anomaly cancellation requires the presence of extra dark leptons in the dark sector. We investigate the signatures of the minimal scenarios of this kind, which involve cascade decays of the extra $Z^{\prime }$ boson into the dark leptons, identifying a four-lepton signal as the most promising one. We estimate the sensitivity to this signal at the LHC, the high-luminosity LHC upgrade, a possible high-energy upgrade, as well as a future circular collider. For $Z^{\prime }$ couplings compatible with current dijet constraints the multilepton signals can reach the $5\sigma$ level already at Run 2 of the LHC. At future colliders, couplings two orders of magnitude smaller than the electroweak coupling can be probed with $5\sigma$ sensitivity.

    hep-phhep-exJHEP(2020)·9 citations
22. 22*

    Jet transition values for the anti-$k_{\perp }$ algorithm

    Zoltán Szőr🇩🇪

    We define jet transition values for the anti-$k_{\perp }$ algorithm for both hadron and $e^{+}{e}^{-}$ colliders. We show how these transition values can be computed and how they can be used to improve the performance of clusterization when jet resolution parameters are varied over a larger set of values. Finally we present a simple performance test to illustrate the behavior of the new method compared to the original one.

    hep-phhep-exEPJC(2020)·1 citation
23. 23*

    Galactic Positron Excess from Selectively Enhanced Dark Matter Annihilation

    Anirban Das🇮🇳 · Basudeb Dasgupta🇮🇳 · Anupam Ray (Tata Inst., Mumbai)🇮🇳

    Precision measurements of the positron flux in cosmic ray have revealed an unexplained bump in the spectrum around $E\simeq 300\mathrm{GeV}$, not clearly attributable to known astrophysical processes. We propose annihilation of dark matter of mass $m_{\chi }=780\mathrm{GeV}$ with a late-time cross section $\sigma v=4.63\times 10^{-24}\mathrm{c}{\mathrm{m}}^3{\mathrm{s}}^{-1}$ as a possible source. The nonmonotonic dependence of the annihilation rate on dark matter velocity, owing to a selective $p$-wave Sommerfeld enhancement, allows such a large signal from the Milky Way without violating corresponding constraints from CMB and dwarf galaxy observations. We briefly explore other signatures of this scenario, and outline avenues to test it in future experiments.

    hep-phastro-ph.COastro-ph.HEPRD(2020)·10 citations
24. 24*

    Probing dark sectors with long-lived particles at BELLE II

    Anastasiia Filimonova🇩🇪 · Ruth Schäfer🇩🇪 · Susanne Westhoff🇩🇪

    We propose a new search for light scalar singlets in rare meson decays. For tiny interactions, the scalar is long-lived at detector scales and decays into displaced pairs of leptons or light mesons. We show that Belle II has a remarkable potential to probe scalars in the GeV range with couplings as small as $10^{-5}$. The predicted sensitivity is higher than at the long-baseline experiments FASER and NA62. We also investigate signatures of invisibly decaying scalars in rare meson decays with missing energy.

    hep-phhep-exPRD(2020)·98 citations
25. 25*

    Interglueball potential in SU(N) lattice gauge theory

    Nodoka Yamanaka🇯🇵 · Hideaki Iida🇯🇵 · Atsushi Nakamura🇷🇺 · Masayuki Wakayama🇰🇷

    We report on our calculation of the interglueball potentials in SU(2), SU(3), and SU(4) lattice Yang-Mills theories using the indirect (so-called HAL QCD) method. We use the cluster decomposition error reduction technique to improve the statistical accuracy of the glueball correlators. After calculating the glueball scattering cross section in SU(2) Yang-Mills theory and combining with the observational data of the dark matter mass distributions, we derive the lower limit on the scale parameter.

    ↳ hep-lathep-phPoS(2019)·5 citations
26. 26*

    Improved limits on solar axions and bosonic dark matter from the CDEX-1B experiment using the profile likelihood ratio method

    Y. Wang🇨🇳 · Q. Yue🇨🇳 · S.K. Liu🇨🇳 · K.J. Kang🇨🇳 · Y.J. Li🇨🇳 · H.P. An🇨🇳 · J.P. Chang🇨🇳 · J.H. Chen🇹🇼 · Y.H. Chen🇨🇳 · J.P. Cheng🇨🇳 · W.H. Dai🇨🇳 · Z. Deng🇨🇳 and 68 other authors

    We present the improved constraints on couplings of solar axions and more generic bosonic dark matter particles using 737.1 kg-days of data from the CDEX-1B experiment. The CDEX-1B experiment, located at the China Jinping Underground Laboratory, primarily aims at the direct detection of weakly interacting massive particles using a p-type point-contact germanium detector. We adopt the profile likelihood ratio method for analysis of data in the presence of backgrounds. An energy threshold of 160 eV was achieved, much better than the 475 eV of CDEX-1A with an exposure of 335.6 kg-days. This significantly improves the sensitivity for the bosonic dark matter below 0.8 keV among germanium detectors. Limits are also placed on the coupling $g_{Ae}<2.48\times 10^{-11}$ from Compton, bremsstrahlung, atomic-recombination and de-excitation channels and $g_{AN}^{eff}\times g_{Ae}<4.14\times 10^{-17}$ from a ${}^{57}$Fe M1 transition at 90\% confidence level.

    ↳ hep-exhep-phphysics.ins-detPRD(2020)·43 citations
27. 27*

    UV Constraints on Massive Spinning Particles: Lessons from the Gravitino

    Scott Melville🇬🇧 · Diederik Roest🇳🇱 · David Stefanyszyn🇬🇧

    Self-interacting massive particles with spin $\ge 1$ unavoidably violate unitarity; the question is at what scale. For spin-$1$ the strong coupling scale (at which perturbative unitarity is lost) cannot be raised by any finite tuning of the interactions, while for spin-$2$ there exists a special tuning of the Wilson coefficients which can raise this scale (and enjoys numerous special properties such as ghost-freedom). Here, we fill in the missing piece by describing how the self-interactions of a massive spin-$3/2$ field, or "massive gravitino", become strongly coupled at high energies. We show that while several different structures appear in the leading order potential, the strong coupling scale cannot be raised (in the absence of additional fields). At the level of the off-shell Lagrangian, it is always the non-linear symmetries of the longitudinal Stuckelberg mode that dictate the strong coupling, and we show that in general it is only possible to parametrically raise the strong coupling scale if Wess-Zumino structures exist. We complement this off-shell approach with a first analysis of positivity bounds for a massive spin-$3/2$ particle, showing that any potential self-interaction which contributes to an on-shell 2-to-2 elastic process at tree level must vanish if this low-energy theory is to have a standard UV completion. We identify the mixing between the longitudinal mode and the transverse modes as the main obstacle to positivity, and clarify how the non-Abelian nature of non-linear (dRGT) massive gravity allows it to satisfy positivity where all known spin $\ge 3/2$ Abelian theories fail. Our results imply that a massive gravitino cannot appear alone in a controlled EFT---it must be accompanied by other particles, e.g.~as part of a supermultiplet. Together with the spin-$1$ and spin-$2$ cases, we suggest features which will persist in even higher spin massive theories.

    ↳ hep-thgr-qchep-phJHEP(2020)·22 citations
28. 28*

    Transport coefficients of hot and dense matter

    O. Soloveva🇩🇪 · P. Moreau🇩🇪 · L. Oliva🇩🇪 · T. Song🇩🇪 · W. Cassing🇩🇪 · E. Bratkovskaya🇩🇪

    We present calculations for the shear viscosity of the hot and dense quark-gluon plasma (QGP) using the partonic scattering cross sections as a function of temperature $T$ and baryon chemical potential ${\mu }_B$ from the dynamical quasiparticle model (DQPM) that is matched to reproduce the equation of state of the partonic system above the deconfinement temperature $T_c$ from lattice QCD. To this aim we calculate the collisional widths for the partonic degrees of freedom at finite $T$ and ${\mu }_B$ in the time-like sector and conclude that the quasiparticle limit holds sufficiently well. Furthermore, the ratio of shear viscosity $\eta$ over entropy density $s$, i.e. $\eta /s$, is evaluated using these collisional widths and are compared to lQCD calculations for ${\mu }_B$ = 0 as well. We find that the ratio $\eta /s$ is in agreement with the results of calculations within the original DQPM on the basis of the Kubo formalism. Furthermore, there is only a very modest change of $\eta /s$ with the baryon chemical ${\mu }_B$ as a function of the scaled temperature $T/T_c({\mu }_B)$.

    ↳ nucl-thhep-phSpringer Proc.Phys.(2020)·4 citations
29. 29*

    Extending and Calibrating the Velocity dependent One-Scale model for Cosmic Strings with One Thousand Field Theory Simulations

    J. R. C. C. C. Correia🇵🇹 · C. J. A. P. Martins🇵🇹

    Understanding the evolution and cosmological consequences of topological defect networks requires a combination of analytic modeling and numerical simulations. The canonical analytic model for defect network evolution is the Velocity-dependent One-Scale (VOS) model. For the case of cosmic strings, this has so far been calibrated using small numbers of Goto-Nambu and field theory simulations, in the radiation and matter eras, as well as in Minkowski spacetime. But the model is only as good as the available simulations, and it should be extended as further simulations become available. In previous work we presented a General Purpose Graphics Processing Unit implementation of the evolution of cosmological domain wall networks, and used it to obtain an improved VOS model for domain walls. Here we continue this effort, exploiting a more recent analogous code for local Abelian-Higgs string networks. The significant gains in speed afforded by this code enabled us to carry out 1032 field theory simulations of $512^3$ size, with 43 different expansion rates. This detailed exploration of the effects of the expansion rate on the network properties in turn enables a statistical separation of various dynamical processes affecting the evolution of the network. We thus extend and accurately calibrate the VOS model for cosmic strings, including separate terms for energy losses due to loop production and scalar/gauge radiation. By comparing this newly calibrated VOS model with the analogous one for domain walls we quantitatively show that energy loss mechanisms are different for the two types of defects.

    ↳ astro-ph.COhep-phphysics.comp-phPRD(2019)·47 citations
30. 30*

    Static force from the lattice

    Nora Brambilla🇩🇪 · Viljami Leino🇩🇪 · Owe Philipsen🇩🇪 · Christian Reisinger🇩🇪 · Antonio Vairo🇩🇪 · Marc Wagner🇩🇪

    We present a novel approach to compute the force between a static quark and a static antiquark from lattice gauge theory directly, rather than extracting it from the static energy. We explore this approach for SU(3) pure gauge theory using the multilevel algorithm and smeared operators.

    ↳ hep-lathep-phPoS(2019)·7 citations
31. 31*

    Hubble-induced phase transitions: Walls are not forever

    Dario Bettoni🇪🇸 · Javier Rubio🇫🇮

    The interplay between non-minimally coupled scalar fields and a kinetic-dominated era following the end of inflation triggers the spontaneous symmetry breaking of internal symmetries and the subsequent evolution of the fields towards large expectation values. We present here a detailed analysis of the associated dynamics in quintessential inflation scenarios involving a non-minimally coupled $Z_2$-symmetric spectator field. By analytically following the evolution of the spectator field fluctuations at early times, we characterize the formation of classical, homogeneous and spatially-localized field configurations separated by domain walls. The life expectancy of these dividing barriers is set by the scale of inflation, the non-minimal coupling and self-interactions of the spectator field and potentially, but not necessarily, the duration of the heating stage. For most of the parameter space, the domain walls are doomed to disappear before big bang nucleosynthesis. Potential phenomenological consequences of the scenario are discussed.

    ↳ astro-ph.COgr-qchep-phJCAP(2020)·47 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.