Fri·Nov 9, 2018Friday·November 9, 2018

1. 01*

   The interplay of hadronic amplitudes and Coulomb phase in LHC measurements at 13 $\mathrm{TeV}$

   A.K.Kohara🇫🇷 · E. Ferreira🇧🇷 · M. Rangel🇧🇷

   Detailed analysis of the measurements of differential cross sections in the forward region of pp elastic scattering at 13 TeV in LHC is performed. The structures of the real and imaginary parts of the scattering amplitude are investigated, both requiring exponential and linear factors. Representations of the data in different conditions are compared, accounting for predictions from dispersion relations and investigating the role of the Coulomb-nuclear interference. The additivity of nuclear and Coulomb eikonal phases to determine the interference phase in pp scattering is submitted to a comparison with assumption of phase equal to zero. The structures of the real part of the scattering amplitude under the two assumptions are examined, and direct comparison is performed with the information extracted from the data. The alternative criteria for the treatment of the interference phase lead to different values for the $\rho$ parameter between 0.1 and 0.13 while $\sigma$ differ by 0.18 mb, and it is shown that the available data cannot discriminate the two models.

   hep-phPLB(2019)·12 citations
2. 02*

   Lepton angular distributions of fixed-target Drell-Yan experiments in perturbative QCD and a geometric approach

   Wen-Chen Chang🇹🇼 · Randall Evan McClellan🇺🇸 · Jen-Chieh Peng🇺🇸 · Oleg Teryaev🇷🇺

   The lepton angular distributions of the Drell-Yan process in fixed-target experiments are investigated by NLO and NNLO perturbative QCD. We present the calculated angular parameters $\lambda$, $\mu$, $\nu$ and the degree of violation of the Lam-Tung relation, $1-\lambda -2\nu$, for the NA10, E615 and E866 experiments. Predictions for the ongoing COMPASS and SeaQuest experiments are also presented. The transverse momentum ($q_T$) distributions of $\lambda$ and $\nu$ show a clear dependence on the dimuon mass ($Q$) while those of $\mu$ have a strong rapidity ($x_F$) dependence. Furthermore, $\lambda$ and $\nu$ are found to scale with $q_T/Q$. These salient features could be qualitatively understood by a geometric approach where the lepton angular distribution parameters are expressed in terms of the polar and azimuthal angles of the "natural axis" in the dilepton rest frame.

   hep-phhep-exnucl-exnucl-thPRD(2019)·19 citations
3. 03*

   Two-step strongly first-order electroweak phase transition modified FIMP dark matter, gravitational wave signals, and the neutrino mass

   Ligong Bian🇨🇳 · Xuewen Liu🇨🇳

   We study a dynamical freeze-in production of the dark matter considering the electroweak phase transition history of the Universe. The kinematical thresholds of the decay and scattering processes for the dark matter production can be altered by the temperature dependent thermal masses of particles, which might lead to enhancement or reduction of the dark matter relic abundance. The second-stage strongly first-order electroweak phase transition (SFOEWPT) triggered by the hidden scalars can be probed at colliders and the gravitational wave detectors. The two-step SFOEWPT modified late decay FIMP dark matter is accomplished with a Dirac neutrino mass explanation in the scotogenic model.

   hep-phastro-ph.COPRD(2019)·50 citations
4. 04*

   Light Fermionic WIMP Dark Matter with Light Scalar Mediator

   Shigeki Matsumoto🇯🇵 · Yue-Lin Sming Tsai🇹🇼 · Po-Yan Tseng🇯🇵

   A light fermionic weakly interacting massive particle (WIMP) dark matter is investigated by studying its minimal renormalizable model, where it requires a scalar mediator to have an interaction between the WIMP and standard model particles. We perform a comprehensive likelihood analysis of the model involving the latest but robust constraints and those will be obtained in the near future. In addition, we pay particular attention to properly take the kinematically equilibrium condition into account. It is shown that near-future experiments and observations such as low-mass direct dark matter detections, flavor experiments and CMB observations play important roles to test the model. Still, a wide parameter region will remain even if no WIMP and mediator signals are detected there. We also show that precise Higgs boson measurements at future lepton colliders will significantly test this remaining region.

   hep-phJHEP(2019)·70 citations
5. 05*

   Adiabatic Electroweak Baryogenesis Driven by an Axion-like Particle

   Kwang Sik Jeong🇰🇷 · Tae Hyun Jung🇰🇷 · Chang Sub Shin🇰🇷

   An axion-like particle (ALP) offers a new direction in electroweak baryogenesis because the periodic nature enables it to trigger a strong first-order phase transition insensitively to the decay constant $f$. For $f$ much above TeV, the ALP-induced electroweak phase transition is approximately described by adiabatic processes, distinguishing our scenario for electroweak baryogenesis from the conventional ones. We show that, coupled to the electroweak anomaly, the ALP can naturally realize spontaneous electroweak baryogenesis to solve the matter-antimatter asymmetry problem for $f$ in the range between about $10^5$ GeV and $10^7$ GeV. In such an ALP window, the $CP$ violation for baryogenesis is totally free from the experimental constraints, especially from the recently improved limit on the electron electric dipole moment. Future searches for ALPs could probe our scenario while revealing the connection between electroweak symmetry breaking and baryogenesis.

   hep-phPRD(2020)·51 citations
6. 06*

   Recent developments on direct $CP$ violation in the kaon system and connection to $K\to \pi \nu \bar{\nu }$ measurements

   Teppei Kitahara🇮🇱

   The first lattice result from the RBC and UKQCD Collaborations and improved perturbative calculations of ${\epsilon }_K^{\prime }/{\epsilon }_K$ have implied that the Standard-Model (SM) expectation deviates from measured values at the $2.8\sigma$ level. Since ${\epsilon }_K^{\prime }/{\epsilon }_K$ comes from $CP$-violating FCNC and is significantly suppressed in the SM, the discrepancy can be explained easily in several new physics (NP) models. In this contribution, it is shown that correlations with the other rare decays, especially $K\to \pi \nu \overline{\nu }$ and $K_S\to {\mu }^{+}{\mu }^{-}$, are crucial for discrimination of the NP models. These channels can be probed precisely in the future by the NA62 and KOTO experiments for $K\to \pi \nu \overline{\nu }$ and LHCb experiment for $K_S\to {\mu }^{+}{\mu }^{-}$.

   hep-phPoS(2018)·0 citations
7. 07*

   Exotic tetraquark states with $J^{PC}=0^{+-}$

   Yi-Chao Fu🇨🇳 · Zhuo-Ran Huang🇨🇳 · Zhu-Feng Zhang🇨🇳 · Wei Chen🇨🇳

   We use the Laplace/Borel sum rules (LSR) and the finite energy/local duality sum rules (FESR) to investigate the non-strange $ud\bar{u}\bar{d}$ and hidden-strange $us\bar{u}\bar{s}$ tetraquark states with exotic quantum numbers $J^{PC}=0^{+-}$ . We systematically construct all eight possible tetraquark currents in this channel without covariant derivative operator. Our analyses show that the $ud\bar{u}\bar{d}$ systems have good behaviour of sum rule stability and expansion series convergence in both the LSR and FESR analyses, while the LSR for the $us\bar{u}\bar{s}$ states do not associate with convergent OPE series in the stability regions and only the FESR can provide valid results. We give the mass predictions $1.43\pm 0.09$ GeV and $1.54\pm 0.12$ GeV for the $ud\bar{u}\bar{d}$ and $us\bar{u}\bar{s}$ tetraquark states, respectively. Our results indicate that the $0^{+-}$ isovector $us\bar{u}\bar{s}$ tetraquark may only decay via weak interaction mechanism, e.g. $X_{us\bar{u}\bar{s}}\to K\pi \pi$, since its strong decays are forbidden by kinematics and the symmetry constraints on the exotic quantum numbers. It is predicted to be very narrow, if it does exist. The $0^{+-}$ isoscalar $us\bar{u}\bar{s}$ tetraquark is also predicted to be not very wide because its dominate decay mode $X_{us\bar{u}\bar{s}}\to \varphi \pi \pi$ is in $P$-wave.

   hep-phhep-exhep-latPRD(2019)·12 citations
8. 08*

   Coupling QCD-scale axion-like particles to gluons

   Daniel Aloni🇮🇱 · Yotam Soreq🇺🇸 · Mike Williams🇺🇸

   We present a novel data-driven method for determining the hadronic interaction strengths of axion-like particles (ALPs) with QCD-scale masses. Using our method, it is possible to calculate the hadronic production and decay rates of ALPs, along with many of the largest ALP decay rate to exclusive final states. To illustrate the impact on QCD-scale ALP phenomenology, we consider the scenario where the ALP-gluon coupling is dominant over the ALP coupling to photons, electroweak bosons, and all fermions for $m_{\pi }\lesssim m_a\lesssim 3$ GeV. We emphasize, however, that our method can easily be generalized to any set of ALP couplings to SM particles. Finally, using the approach developed here, we provide calculations for the branching fractions of ${\eta }_c\to VV$ decays, i.e. ${\eta }_c$ decays into two vector mesons, which are consistent with the known experimental values.

   hep-phhep-exPRL(2019)·188 citations
9. 09*

   Low scale type II seesaw: Present constraints and prospects for displaced vertex searches

   Stefan Antusch🇨🇭 · Oliver Fischer🇩🇪 · A. Hammad🇨🇭 · Christiane Scherb🇨🇭

   The type II seesaw mechanism is an attractive way to generate the observed light neutrino masses. It postulates a SU(2)${}_{\mathrm{L}}$-triplet scalar field, which develops an induced vacuum expectation value after electroweak symmetry breaking, giving masses to the neutrinos via its couplings to the lepton SU(2)${}_{\mathrm{L}}$-doublets. When the components of the triplet field have masses around the electroweak scale, the model features a rich phenomenology. We discuss the current allowed parameter space of the minimal low scale type II seesaw model, taking into account all relevant constraints, including charged lepton flavour violation as well as collider searches. We point out that the symmetry protected low scale type II seesaw scenario, where an approximate "lepton number"-like symmetry suppresses the Yukawa couplings of the triplet to the lepton doublets, is still largely untested by the current LHC results. In part of this parameter space the triplet components can be long-lived, potentially leading to a characteristic displaced vertex signature where the doubly-charged component decays into same-sign charged leptons. By performing a detailed analysis at the reconstructed level we find that already at the current run of the LHC a discovery would be possible for the considered parameter point, via dedicated searches for displaced vertex signatures. The discovery prospects are further improved at the HL-LHC and the FCC-hh/SppC.

   hep-phJHEP(2019)·73 citations
10. 10*

    Unification of Flavor SU(3) Analyses of Heavy Hadron Weak Decays

    Xiao-Gang He🇹🇼 · Yu-Ji Shi🇨🇳 · Wei Wang🇨🇳

    Analyses of heavy mesons and baryons hadronic charmless decays using the flavor SU(3) symemtry can be formulated in two different forms. One is to construct the SU(3) irreducible representation amplitude (IRA) by decomposing effective Hamiltonian, and the other is to draw the topological diagrams (TDA). In the flavor SU(3) limit, we study various $B/D\to PP,VP,VV$, $B_c\to DP/DV$ decays, and two-body nonleptonic decays of beauty/charm baryons, and demonstrate that when all terms are included these two ways of analyzing the decay amplitudes are completely equivalent. Furthermore we clarify some confusions in drawing topological diagrams using different ways of describing beauty/charm baryons.

    hep-phEPJC(2020)·80 citations
11. 11*

    Tritium beta decay with additional emission of new light bosons

    Giorgio Arcadi🇩🇪 · Julian Heeck🇧🇪 · Florian Heizmann🇩🇪 · Susanne Mertens🇩🇪 · Farinaldo S. Queiroz🇧🇷 · Werner Rodejohann🇩🇪 · Martin Slezák🇩🇪 · Kathrin Valerius🇩🇪

    We consider tritium beta decay with additional emission of light pseudoscalar or vector bosons coupling to electrons or neutrinos. The electron energy spectrum for all cases is evaluated and shown to be well estimated by approximated analytical expressions. We give the statistical sensitivity of KATRIN to the mass and coupling of the new bosons, both in the standard setup of the experiment as well as for future modifications in which the full energy spectrum of tritium decay is accessible.

    hep-phhep-exJHEP(2019)·30 citations
12. 12*

    A novel approach to the computation of one-loop three- and four-point functions. I -- The real mass case

    J. Ph. Guillet (1)🇫🇷 · E. Pilon (1)🇫🇷 · Y. Shimizu (2)🇯🇵 · M. S. Zidi (3) ((1) Univ. Savoie Mont Blanc, CNRS, LAPTH, Annecy, France, (2) KEK, Tsukuba, Japan, (3) LPTh, Université de Jijel, Jijel, Algérie)🇩🇿

    This article is the first of a series of three presenting an alternative method to compute the one-loop scalar integrals. This novel method enjoys a couple of interesting features as compared with the method closely following 't Hooft and Veltman adopted previously. It directly proceeds in terms of the quantities driving algebraic reduction methods. It applies to the three-point functions and, in a similar way, to the four-point functions. It also extends to complex masses without much complication. Lastly, it extends to kinematics more general than the one of physical e.g.\ collider processes relevant at one loop. This last feature may be useful when considering the application of this method beyond one loop using generalised one-loop integrals as building blocks.

    hep-phPTEP(2019)·7 citations
13. 13*

    $R_{D^{(\ast )}}$ motivated ${\mathcal{S}}_1$ leptoquark scenarios: Impact of interference on the exclusion limits from LHC data

    Tanumoy Mandal🇸🇪 · Subhadip Mitra🇮🇳 · Swapnil Raz🇮🇳

    Motivated by the persistent anomalies in the semileptonic $B$-meson decays, we investigate the competency of LHC data to constrain the $R_{D^{(\ast )}}$-favoured parameter space in a charge $-1/3$ scalar leptoquark (${\mathcal{S}}_1$) model. We consider some scenarios with one large free coupling to accommodate the $R_{D^{(\ast )}}$ anomalies. As a result, some of them dominantly yield nonresonant $\tau \tau$ and $\tau \nu$ events at the LHC through the $t$-channel ${\mathcal{S}}_1$ exchange. So far, no experiment has searched for leptoquarks using these signatures and the relevant resonant leptoquark searches are yet to put any strong exclusion limit on the parameter space. We recast the latest $\tau \tau$ and $\tau \nu$ resonance search data to obtain new exclusion limits. The nonresonant processes strongly interfere (destructively in our case) with the Standard Model background and play the determining role in setting the exclusion limits. To obtain precise limits, we include non-negligible effects coming from the subdominant (resonant) pair and inclusive single leptoquark productions systematically in our analysis. To deal with large destructive interference, we make use of the transverse mass distributions from the experiments in our statistical analysis. In addition, we also recast the relevant direct search results to obtain the most stringent collider bounds on these scenarios to date. These are independent bounds and are competitive to other known bounds. Finally, we indicate how one can adopt these bounds to a wide class of models with ${\mathcal{S}}_1$ that are proposed to accommodate the $R_{D^{(\ast )}}$ anomalies.

    hep-phhep-exPRD(2019)·80 citations
14. 14*

    Probing Pseudoscalars with Pulsar Polarisation Data Sets

    Karam Chand🇮🇳 · Subhayan Mandal🇮🇳

    Recently a data set containing linear and circular polarisation information of a collection of six hundred pulsars has been released. The operative radio wavelength for the same was 21 cm. Pulsars radio emission process is modelled either with synchroton / superconducting self-Compton route or with curvature radiation route. These theories fall short of accounting for the circular polarisation observed, as they are predisposed towards producing, solely, linear polarisation. Here we invoke (pseudo)scalars and their interaction with photons mediated by colossal magnetic fields of pulsars, to account for the circular part of polarisation data. This enables us to estimate the pseudoscalar parameters such as its coupling to photons and its mass in conjunction as product. To obtain these values separately, we turn our attention to recent observation on 47 pulsars, whose absolute polarisation position angles have been made available. Except, a third of the latter set, the rest of it overlaps with the expansive former data set on polarisation type \& degree. This helps us figure out, both the pseudoscalar parameters individually, that we report here.

    hep-phastro-ph.HEAstrophysics(2024)·1 citation
15. 15*

    Homeopathic Dark Matter, or how diluted heavy substances produce high energy cosmic rays

    Marco Cirelli🇫🇷 · Yann Gouttenoire🇩🇪 · Kalliopi Petraki🇫🇷 · Filippo Sala🇩🇪

    We point out that current and planned telescopes have the potential of probing annihilating Dark Matter (DM) with a mass of O(100) TeV and beyond. As a target for such searches, we propose models where DM annihilates into lighter mediators, themselves decaying into Standard Model (SM) particles. These models allow to reliably compute the energy spectra of the SM final states, and to naturally evade the unitarity bound on the DM mass. Indeed, long-lived mediators may cause an early matter-dominated phase in the evolution of the Universe and, upon decaying, dilute the density of preexisting relics thus allowing for very large DM masses. We compute this dilution in detail and provide results in a ready-to-use form. Considering for concreteness a model of dark U(1) DM, we then study both dilution and the signals at various high energy telescopes observing gamma rays, neutrinos and charged cosmic rays. This study enriches the physics case of these experiments, and opens a new observational window on heavy new physics sectors.

    hep-phastro-ph.COastro-ph.HEJCAP(2019)·96 citations
16. 16*

    Higgs Inflation and the Refined dS Conjecture

    Dhong Yeon Cheong🇰🇷 · Sung Mook Lee🇰🇷 · Seong Chan Park🇰🇷

    The refined de Sitter derivative conjecture provides constraints to potentials that are low energy effective theories of quantum gravity. It can give direct bounds on inflationary scenarios and determine whether the theory is in the Landscape or the Swampland. We consider the `Higgs inflation' scenario taking the refined de Sitter derivative conjecture into account. Obtaining the critical lines for the potential, we find a conjecture parameter space in which the `Higgs inflation' is to be in the Landscape. Comparing with the model independent observational bounds from recent data we find that the observational bounds represent the Higgs inflation can be in the Landscape.

    hep-phhep-thPLB(2019)·50 citations
17. 17*

    LHC constraints and potential on resonant monotop production

    Giacomo Cacciapaglia🇫🇷 · Eric Conte🇫🇷 · Aldo Deandrea🇫🇷 · Benjamin Fuks🇫🇷 · Hua-Sheng Shao🇫🇷

    We discuss the phenomenology associated with a resonant monotop collider signal, i.e. a signal in which a single top quark is resonantly produced in association with missing energy through an s-channel scalar exchange. We study both the bounds originating from dedicated monotop searches performed by the ATLAS and CMS experiments, and the constraints associated with other processes that could be induced by a new physics context favouring monotop production at colliders. The latter class of constraints includes, in particular, the recasting of analyses from the LHC and the TeVatron. All theoretical calculations are performed at the next-to-leading order accuracy in QCD, and we finally combine all results to establish the present limits on the parameter space and test the relevance of the monotop signal at the LHC Run 2.

    hep-phEPJC(2019)·7 citations
18. 18*

    Exclusive Top Threshold Matching at Lepton Colliders

    Jürgen Reuter🇩🇪 · Bijan Chokoufé Nejad🇩🇪 · Andre Hoang🇦🇹 · Wolfgang Kilian🇩🇪 · Maximilian Stahlhofen🇩🇪 · Thomas Teubner🇬🇧 · Christian Weiss🇩🇪

    The threshold scan at future lepton colliders is the most precise known method to determine the top quark mass (well below 100 MeV), a fundamental parameter of the Standard Model that co-determines the stability properties of the electroweak vacuum. We present a new method to match the continuum next-to-leading order QCD corrections with the next-to-leading logarithmic resummation of the Coulomb singularities of the quasi-toponium bound state at threshold where fixed-order perturbation theory is invalid. This matching is performed at the level of the fully exclusive $W^{+}b{W}^{-}\bar{b}$ final state. It allows to study all kinds of differential distributions at or close to threshold. The top mass dependence of these distributions opens up new possibilities for the top mass determination that might be competitive with the inclusive threshold scan.

    hep-phPoS(2019)·4 citations
19. 19*

    Monte Carlo, fitting and Machine Learning for Tau leptons

    V. Cherepanov🇫🇷 · E. Richter-Was🇵🇱 · Z. Was🇵🇱

    Status of tau lepton decay Monte Carlo generator TAUOLA, and its main recent applications are reviewed. It is underlined, that in recent efforts on development of new hadronic currents, the multi-dimensional nature of distributions of the experimental data must be taken with a great care. Studies for H to tau tau; tau to hadrons indeed demonstrate that multi-dimensional nature of distributions is important and available for evaluation of observables where tau leptons are used to constrain experimental data. For that part of the presentation, use of the TAUOLA program for phenomenology of H and Z decays at LHC is discussed, in particular in the context of the Higgs boson parity measurements with the use of Machine Learning techniques. Some additions, relevant for QED lepton pair emission and electroweak corrections are mentioned as well.

    hep-phSciPost Phys.Proc.(2019)·9 citations
20. 20*

    Probing AdS/QCD backgrounds with semi-classical strings

    Saulo Diles🇧🇷

    New AdS/QCD backgrounds have been proposed to describe the spectrum of heavy vector mesons via the implementation of additional energy scales on the bulk geometry of the soft wall model. The extra energy scales are needed to include the decay constants of hadronic states when describing the radial excitations of the heavy meson. Here we analyze one model that introduces an ultraviolet cutoff on Anti de-Sitter space and a model that consider a dilaton profile modified by the addition of an extra term and no cutoff. For each one of these two models we consider the presence of a semi-classical string in the bulk that is dual to a static and infinitely heavy meson. We compute the expected value of the Wilson loop operator using the holographic dictionary and obtain the dual potential for the static $q\bar{q}$ pair. For the model with modified dilaton profile the on-shell string action presents a peculiar ultraviolet divergence, a compatible regularization is discussed and a new subtraction scheme is used. We consider the case of finite temperature and determine how the dissociation temperature of the heavy meson is affected by the additional energy scales.

    ↳ hep-thhep-phEPL(2020)·6 citations
21. 21*

    Sensitivity enhancement for a light axion dark matter search with magnetic material

    Alexander V. Gramolin🇺🇸 · Deniz Aybas🇺🇸 · Dorian Johnson🇺🇸 · Janos Adam🇺🇸 · Alexander O. Sushkov🇺🇸

    The sensitivity of experimental searches for axion dark matter coupled to photons is typically proportional to the strength of the applied static magnetic field. We demonstrate how a permeable material can be used to enhance the magnitude of this static magnetic field, and therefore improve the sensitivity of such searches in the low frequency lumped-circuit limit. Using gadolinium iron garnet toroids at temperature 4.2 K results in a factor of 4 enhancement compared to an air-core toroidal design. The enhancement is limited by magnetic saturation. Correlation of signals from three such toroids allows efficient rejection of systematics due to electromagnetic interference. The sensitivity of a centimeter-scale axion dark matter search based on this approach is on the order of $g_{a\gamma \gamma }\approx 10^{-9}$ GeV${}^{-1}$ after 8 hours of data collection for axion masses near $10^{-10}$ eV. This approach may substantially extend the sensitivity reach of large-volume lumped element axion dark matter searches.

    ↳ physics.ins-dethep-exhep-ph5 citations
22. 22*

    Radiative $B$ Decays at Belle

    Akimasa Ishikawa🇯🇵

    We report recent results on radiative $B$ decays at Belle at the KEKB collider.

    ↳ hep-exhep-phPoS(2019)·1 citation
23. 23*

    Collective neutrino oscillations and detectabilities in failed supernovae

    Masamichi Zaizen🇯🇵 · Takashi Yoshida🇯🇵 · Kohsuke Sumiyoshi🇯🇵 · Hideyuki Umeda🇯🇵

    We investigate the collective neutrino oscillations under the three flavor multi-angle approximation in a spherically symmetric simulation of failed supernovae. A failed supernova emits high neutrino fluxes in a short time, while intense accretion proceeds with high electron density enough to experience re-collapse into a black hole. Our results show that matter-induced effects completely dominate over neutrino self-interaction effects and multi-angle matter suppression occurs at all time snapshots we studied. These facts suggest us that only MSW resonances affect the neutrino flavor conversions in failed supernovae and simple spectra will be observed at neutrino detectors. We also estimate the neutrino event rate in current and future neutrino detectors from a source at 10 kpc as a Galactic event. The time evolution of neutrino detection could provide information about the dense and hot matter and constrain the neutrino mass ordering problem.

    ↳ astro-ph.HEhep-phPRD(2018)·12 citations
24. 24*

    Exploratory study of the off-shell properties of the weak vector bosons

    Axel Maas🇦🇹 · Sebastian Raubitzek🇦🇹 · Pascal Törek🇦🇹

    Gauge invariance requires even in the weak interactions that physical, observable particles are described by gauge-invariant composite operators. Such operators have the same structure as those describing bound states, and consequently the physical versions of the $W^{\pm }$, the $Z$, and the Higgs should have some kind of substructure. To test this consequence, we use lattice gauge theory to study the physical weak vector bosons off-shell, especially their form-factor and weak radius, and compare the results to the ones for the elementary particles. We find that the physical particles show substantial deviations from the structure of a point-like particle. At the same time the gauge-dependent elementary particles exhibit unphysical behavior.

    ↳ hep-lathep-phPRD(2019)·23 citations
25. 25*

    Signs of Dynamical Dark Energy in Current Observations

    Joan Sola Peracaula🇪🇸 · Adria Gomez-Valent🇪🇸 · Javier de Cruz Perez🇪🇸

    Investigations on dark energy (DE) are currently inconclusive about its time evolution. Hints of this possibility do however glow now and then in the horizon. Herein we assess the current status of dynamical dark energy (DDE) in the light of a large body of updated $SNIa+H(z)+BAO+LSS+CMB$ observations, using the full Planck 2015 CMB likelihood. The performance of the $\Lambda$CDM model (with equation of state $w=-1$ for $\Lambda$) is confronted with that of the general XCDM and CPL parametrizations, as well as with the traditional $\Phi$CDM model based on the scalar field potential $V\sim {\Phi }^{-\alpha }$. In particular, we gauge the impact of the bispectrum in the LSS and BAO parts, and show that the subset of $CMB+BAO+LSS$ observations may contain the bulk of the DDE signal. The departure from $w=-1$ is significant: roughly $2.6\sigma$ for XCDM and $2.9\sigma$ for $\Phi$CDM. In both cases the full Bayesian evidence is found to be positive even for a prior range of the DDE parameters extending over several standard deviations from the mean when the bispectrum is taken into account. Positive signs follow as well from the preliminary results of Planck 2018 data using the compressed CMB likelihood. As a bonus we also find that the ${\sigma }_8$-tension becomes reduced with DDE.

    ↳ astro-ph.COgr-qchep-phhep-thPhys.Dark Univ.(2019)·103 citations
26. 26*

    Hunting Axion Dark Matter with Protoplanetary Disk Polarimetry

    Tomohiro Fujita🇯🇵 · Ryo Tazaki🇯🇵 · Kenji Toma🇯🇵

    We find that the polarimetric observations of protoplanetary disks are useful to search for ultra-light axion dark matter. Axion dark matter predicts the rotation of the linear polarization plane of propagating light, and protoplanetary disks are ideal targets to observe it. We show that a recent observation puts the tightest constraint on the axion-photon coupling constant for axion mass $m\lesssim 10^{-21}$eV.

    ↳ astro-ph.COastro-ph.EPhep-phPRL(2019)·71 citations
27. 27*

    Blazar VHE spectral alterations induced by photon-ALP oscillations

    Giorgio Galanti🇮🇹 · Fabrizio Tavecchio🇮🇹 · Marco Roncadelli🇮🇹 · Carmelo Evoli🇮🇹

    Prompted by the increasing interest of axion-like particles (ALPs) for very-high-energy (VHE) astrophysics, we have considered a full scenario for the propagation of a VHE photon/ALP beam emitted by a BL Lac and reaching us in the light of the most up-to-date astrophysical information and for energies up to above $100\mathrm{TeV}$. During its trip, the beam -- generated in a small region of a BL Lac jet -- crosses a variety of magnetic structures in very different astronomical environments: the BL Lac jet, the host elliptical galaxy, the extragalactic space and the Milky Way. We have taken an effort to model all these magnetic fields in the most realistic fashion and using a new model developed by us concerning the extragalactic magnetic field. Assuming an intrinsic spectrum with a power law exponentially truncated at a fixed cut-off energy, we have evaluated the resulting observed spectra of Markarian 501, the extreme BL Lac 1ES 0229+200 and a similar source located at $z=0.6$ up to above $100\mathrm{TeV}$. We obtain interesting results: the model with photon-ALP oscillations possesses features (spectral energy oscillatory behaviour and photon excess above $20\mathrm{TeV}$) which can be tested by $\gamma$-ray observatories like CTA, HAWC, GAMMA 400, LHAASO, TAIGA-HiSCORE and HERD. In addition, our ALP can be detected in dedicated laboratory experiments like the upgrade of ALPS II at DESY, the planned IAXO and STAX experiments, as well as with other techniques developed by Avignone and collaborators.

    ↳ astro-ph.HEhep-phMNRAS(2019)·71 citations
28. 28*

    BRST invariant RG flows

    Shimasadat Asnafi🇮🇷 · Holger Gies🇩🇪 · Luca Zambelli🇩🇪

    A mass parameter for the gauge bosons in gauge-fixed four-dimensional Yang-Mills theory can be accommodated in a local and manifestly BRST-invariant action. The construction is based on the Faddeev-Popov method involving a nonlinear gauge-fixing and a background Nakanishi-Lautrup field. When applied to momentum-dependent masslike deformations, this formalism leads to a full regularization of the theory which explicitly preserves BRST symmetry. We deduce a functional renormalization group equation for the one-particle-irreducible effective action, which has a one-loop form. The master equation is compatible with it, i.e. BRST symmetry is preserved along the flow, and it has a standard regulator-independent Zinn-Justin form. As a first application, we compute the leading-order gluon wave-function renormalization.

    ↳ hep-thhep-phPRD(2019)·20 citations
29. 29*

    Digitizing Gauge Fields: Lattice Monte Carlo Results for Future Quantum Computers

    Daniel C. Hackett🇺🇸 · Kiel Howe🇺🇸 · Ciaran Hughes🇺🇸 · William Jay🇺🇸 · Ethan T. Neil🇺🇸 · James N. Simone🇺🇸

    In the near-future noisy intermediate-scale quantum (NISQ) era of quantum computing technology, applications of quantum computing will be limited to calculations of very modest scales in terms of the number of qubits used. The need to represent numeric quantities using limited resources leads to digitization errors which must be taken into account. As a first step towards quantum simulations of realistic high-energy physics problems, we explore classically the effects of digitizing elements of the $\mathrm{SU}(2)$ gauge group to a finite set. We consider several methods for digitizing the group, finding the best performance from an action-preserving projection onto a mesh. Working in (3+1) dimensions, we find that using $\sim 7$ (qu)bits to represent each $\mathrm{SU}(2)$ gauge link induces a digitization error on the order of $10\%$ in short-distance observables and $2\%$ in long-distance observables. Promisingly, our results indicate that each $\mathrm{SU}(2)$ gauge link can be represented by $\mathcal{O}(10)$ (qu)bits, from which we estimate that a $16^3$ $\mathrm{SU}(2)$ lattice could be simulated with no more than $\mathcal{O}(10^5)$ (qu)bits. Our results on digitization are also of interest as a form of lossy compression that could be used in high-performance classical computing to alleviate communications bottlenecks.

    ↳ quant-phhep-lathep-phhep-thPRA(2019)·81 citations
30. 30*

    The Spur and the Gap in GD-1: Dynamical evidence for a dark substructure in the Milky Way halo

    Ana Bonaca🇺🇸 · David W. Hogg🇺🇸 · Adrian M. Price-Whelan🇺🇸 · Charlie Conroy🇺🇸

    We present a model for the interaction of the GD-1 stellar stream with a massive perturber that naturally explains many of the observed stream features, including a gap and an off-stream spur of stars. The model involves an impulse by a fast encounter, after which the stream grows a loop of stars at different orbital energies. At specific viewing angles, this loop appears offset from the stream track. A quantitative comparison of the spur and gap features prefers models where the perturber is in the mass range of $10^6{\mathrm{M}}_{\odot }$ to $10^8{\mathrm{M}}_{\odot }$. Orbit integrations back in time show that the stream encounter could not have been caused by any known globular cluster or dwarf galaxy with a determined orbit, and mass, size and impact-parameter arguments show that it could not have been caused by a molecular cloud in the Milky Way disk. The most plausible explanation for the gap-and-spur structure is an encounter with a dark-matter substructure, like those predicted to populate galactic halos in LCDM cosmology. However, the expected densities of LCDM subhalos in this mass range and in this part of the Milky Way are $2-3\sigma$ lower than the inferred density of the GD-1 perturber. This observation opens up the possibility that detailed observations of streams could measure the mass spectrum of dark-matter substructures and even identify individual substructures and their orbits in the Galactic halo.

    ↳ astro-ph.GAastro-ph.COhep-ph151 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.