Wed·Feb 5, 2020Wednesday·February 5, 2020

1. 01*

   Suppression of the Higgs Dimuon Decay

   P.M. Ferreira🇵🇹 · Marc Sher🇺🇸

   It is often stated that elimination of tree-level flavor-changing neutral currents in multi-Higgs models requires that all fermions of a given charge to couple to the same Higgs boson. A counterexample was provided by Abe, Sato and Yagyu in a muon-specific two-Higgs doublet model with a softly-broken $Z_4$ symmetry. In this model, all fermions except the muon couple to one Higgs and the muon couples to the other. We study the phenomenology of the model and show that there is a wide range of parameter-space in which the branching ratios of the 125 GeV Higgs are very close to their Standard Model values, with the exception of the branching ratio into muons, which can be substantially suppressed -- this is an interesting possibility, since the current value of this branching ratio is $0.5\pm 0.7$ times the Standard Model value. We also study the charged Higgs boson and show that, if it is lighter than $200$ GeV, it could have a large branching ratio into $\mu \nu$ - even substantially larger than the usual decay into $\tau \nu$. The decays of the heavy neutral scalars are also studied. The model does have a relationship between the branching ratios of the 125 GeV Higgs into $Z$'s, $\tau$'s and $\mu$'s, which can be tested in future accelerators.

   hep-phPRD(2020)·5 citations
2. 02*

   Beyond the Standard Model, guided by Lepton Universality

   Nejc Košnik🇸🇮

   We discuss the current status of lepton flavour universality observables in semileptonic charged and neutral current $B$ meson decays. We recapitulate the current experimental situation. Assuming the current tensions with the SM are of beyond the Standard Model origin we present their implications for the effective theory couplings. Then we discuss general leptoquark models before finally focussing on the model with two scalar leptoquarks ($R_2$ and $S_3$) which have couplings connected by the underlying Grand Unified Theory framework. We present the viability of the model with regard to lepton flavour universality and present opportunities to search for this model in future high-intensity and high-energy experiments

   hep-phPoS(2020)·0 citations
3. 03*

   Lattice QCD (focus on Charm and Beauty form factors, $R(D^{\ast })$, $b$- & $c$-quark masses)

   Oliver Witzel🇺🇸

   We present an overview of state of the art lattice quantum chromodynamcis calculations for heavy-light quantities. Special focus is given to the calculation of form factors for semi-leptonic decays of $B_{(s)}$ and $D$ mesons, the extraction of the Cabibbo-Kobayashi-Maskawa matrix elements $|V_{ub}|$ and $|V_{cb}|$ as well as the determination of $R(D^{(\ast )})$ testing the universality of lepton flavors in $b\to c$ transitions. In addition we report on the determination of $b$ and $c$ quark masses as well as on neutral $B_{(s)}$ meson mixing. Recent results are summarized and new developments highlighted.

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

   Investigation of Higgs boson anomalous FCNC interactions in the simple 3-3-1 model

   D. T. Huong🇻🇳 · N. T. Duy🇻🇳

   We study phenomenological constraints on a simple $3-3-1$ model with flavor violating Yukawa couplings. Both triplets Higgs couple to leptons and quarks, which generates flavor violating signals in both lepton and quark sectors. We have shown that this model can allow for large Higgs lepton flavor-violating rate decay $h\to \mu \tau$ and also can be reached to perfect agreements with other experimental constraints such as $\tau \to \mu \gamma$ and $(g-2{)}_{\mu }$. The contributions of flavor-changing neutral current (FCNC) couplings, Higgs-quark-quark couplings, to the mesons mixing are investigated. Br$(h\to q{q}^{\prime })$ can be enhanced with keeping from the measurements of meson mixing. The branching ratio for $t\to qh$ can reach up to $10^{-3}$, but it could be as low as $10^{-8}$.

   hep-phEPJC(2020)·6 citations
5. 05*

   Cosmological Signatures of Superheavy Dark Matter

   Lingfeng Li🇨🇳 · Shiyun Lu🇨🇳 · Yi Wang🇨🇳 · Siyi Zhou🇸🇪

   We discuss two possible scenarios, namely the curvaton mechanism and the dark matter density modulation, where non-Gaussianity signals of superheavy dark matter produced by gravity can be enhanced and observed. In both scenarios, superheavy dark matter couples to an additional light field as a mediator. In the case of derivative coupling, the resulting non-Gaussianities induced by the light field can be large, which can provide inflationary evidences for these superheavy dark matter scenarios.

   hep-phastro-ph.COhep-thJHEP(2020)·55 citations
6. 06*

   Contributions to $\Delta N_{eff}$ from the dark photon of $U(1{)}_{T3R}$

   Bhaskar Dutta🇺🇸 · Sumit Ghosh🇺🇸 · Jason Kumar🇺🇸

   We consider the effect on early Universe cosmology of the dark photon associated with the gauging of $U(1{)}_{T3R}$, a symmetry group under which only right-handed Standard Model fermions transform non-trivially. We find that cosmological constraints on this scenario are qualitatively much more severe than on other well-studied cases of a new $U(1)$ gauge group, because the dark photon couples to chiral fermions. In particular, the dark photon of $U(1{)}_{T3R}$ is always produced and equilibrates in the early Universe, no matter how small the gauge coupling, unless the symmetry-breaking scale is extremely large. This occurs because, no matter how the weak the coupling, the Goldstone mode (equivalently, the longitudinal polarization) does not decouple. As a result, even the limit of an extremely light and weakly-coupled dark photon of $U(1{)}_{T3R}$ is effectively ruled out by cosmological constraints, unless the symmetry-breaking scale is extremely large. We also discuss the possibility of ameliorating Hubble tension in this model.

   hep-phastro-ph.COPRD(2020)·16 citations
7. 07*

   Combined search for anisotropic birefringence in the gravitational-wave transient catalog GWTC-1

   Lijing Shao🇨🇳

   The discovery of gravitational waves (GWs) provides an unprecedented arena to test general relativity, including the gravitational Lorentz invariance violation (gLIV). In the propagation of GWs, a generic gLIV leads to anisotropy, dispersion, and birefringence. GW events constrain the anisotropic birefringence particularly well. Kostelecký and Mewes (2016) performed a preliminary analysis for GW150914. We improve their method and extend the analysis systematically to the whole GW transient catalog, GWTC-1. This is the first global analysis of the spacetime anisotropic Lorentzian structure with a catalog of GWs, where multiple events are crucial in breaking the degeneracy among gLIV parameters. With the absence of abnormal propagation, we obtain new limits on 34 coefficients for gLIV in the nonminimal gravity that surpass previous limits by $\sim 10^2$-$10^5$.

   hep-phastro-ph.HEgr-qcPRD(2020)·66 citations
8. 08*

   The fate of the axial anomaly in a finite field theory

   Pierre Grangé🇫🇷 · Jean-François Mathiot🇫🇷 · Ernst Werner🇩🇪

   The conservation of the vector current and the axial anomaly responsible for the ${\pi }_0\to \gamma \gamma$ decay amplitude are obtained in leading order within the Taylor-Lagrange formulation of fields considered as operator-valued distributions. As for gauge theories, where this formulation eliminates all divergences and preserves gauge-symmetry, it is shown that the different contributions can be evaluated directly in $4$-dimensional space-time, with no restrictions whatsoever on the four-momentum of the internal loop, and without the need to introduce any additional non physical degrees of freedom like Pauli-Villars fields. We comment on the similar contributions responsible for the decay of the Higgs boson into two photons.

   hep-phhep-thInt.J.Mod.Phys.A(2020)·3 citations
9. 09*

   Tomography of light mesons in light-cone quark model

   Satvir Kaur🇮🇳 · Narinder Kumar🇮🇳 · Jiangshan Lan🇨🇳 · Chandan Mondal🇨🇳 · Harleen Dahiya🇮🇳

   We investigate the tomographical structure of pion and kaon in light cone quark model (LCQM). In particular, we study the parton distribution amplitude (PDA) of pion and kaon. We obtain the parton distribution function (PDF) and the generalized parton distributions (GPDs) of the pion and kaon. The valence quark PDA and PDF of pion, after QCD evolution, are found to be consistent with the data from the E791 and the E615 experiments at Fermilab, respectively. Further, we investigate the transverse momentum distributions (TMDs) of pion and kaon. We also discuss the unpolarized TMD evolution for pion and kaon in this model.

   hep-phPRD(2020)·32 citations
10. 10*

    QCD equation of state at vanishing and high baryon density: Chiral Mean Field model

    Anton Motornenko🇩🇪 · Jan Steinheimer🇩🇪 · Volodymyr Vovchenko🇩🇪 · Stefan Schramm🇩🇪 · Horst Stoecker🇩🇪

    The thermodynamic properties of high temperature and high density QCD-matter are studied using the Chiral SU(3)-flavor parity-doublet Polyakov-loop quark-hadron mean-field model, CMF. The CMF model provides a proper description of lattice QCD data, heavy-ions physics, and static neutron stars. The behavior of lines of constant pressure with increase of baryon density is discussed. The rapid change of pressure behavior at ${\mu }_B/T\approx 3$ suggests a strong contribution of baryons to thermodynamic properties at this region. The position of this region is very close to the radius of convergence for a Taylor expansion of the QCD pressure. The role of mesons and unstable hadrons in the hydrodynamic expansion of strongly interacting matter is also discussed.

    hep-phastro-ph.HEnucl-thNPA(2021)·6 citations
11. 11*

    Chargino production at the ILC

    María Teresa Núñez Pardo de Vera🇩🇪 · Mikael Berggren🇩🇪 · Jenny List🇩🇪

    The lighter chargino, ${\tilde{\chi }}_1^{\pm }$, is a prime candidate to be the next-to-lightest SUSY particle (the NLSP). Several analyses of ${\tilde{\chi }}_1^{\pm }$ pair-production at the ILC, at specific model-points, have been performed, showing that detection and property-determination is possible, even for very difficult cases. However, no recent studies have evaluated the reach of the ILC to detect ${\tilde{\chi }}_1^{\pm }$ pair production in general. In this study, cross sections for ${\tilde{\chi }}_1^{\pm }$ pair production at the ILC were evaluated within a wide range of parameters. The aim was to determine the conditions for the lowest cross sections and compare these worst-case values with an estimation of the cross section limit for the observation of the lightest charginos at the ILC. The estimated limits were extrapolated from the studies performed at LEP, which can also be regarded as a worst-case scenario, since the tremendous advances in detector and accelerator technologies are disregarded

    hep-phhep-ex21 citations
12. 12*

    Gluon Sivers function and transverse single spin asymmetries in $e+p^{\uparrow }\to \gamma +X$

    Siddhesh Padval🇮🇳 · Rohini M. Godbole🇮🇳 · Abhiram Kaushik🇮🇳 · Anuradha Misra🇮🇳 · Vaibhav S. Rawoot🇮🇳

    We present estimates of transverse single-spin asymmetry in prompt photon production in the scattering of low virtuality photons off a polarized proton target and discuss the possibility of using this as a probe to get information about the gluon Sivers function (GSF). Using a generalized parton model (GPM) framework, we estimate the asymmetries at electron-ion collider energy ($\sqrt{s}$ =140 GeV) taking into account both direct and resolved photon processes and find that the dominant contribution, up to $10\%$, comes from quark Sivers function (QSF) while the contribution from GSF is found to be up to $2\%$. However, upon taking into account the effects of the process-dependent initial and final state interactions through the color-gauge invariant generalized parton model approach we find that the situation is significantly changed, with near zero contributions from the QSFs and up to a $1\%$ level contribution from the \textit{f}-type GSF. Our results indicate that this process may be useful for distinguishing between GPM and color-gauge invariant generalized parton models and can be used as a good probe of \textit{f}-type GSF.

    hep-phPRD(2021)·3 citations
13. 13*

    Implications for Electric Dipole Moments of a Leptoquark Scenario for the $B$-Physics Anomalies

    Wolfgang Altmannshofer🇺🇸 · Stefania Gori🇺🇸 · Hiren H. Patel🇺🇸 · Stefano Profumo🇺🇸 · Douglas Tuckler🇺🇸

    Vector leptoquarks can address the lepton flavor universality anomalies in decays associated with the $b\to c\ell \nu$ and $b\to s\ell \ell$ transitions, as observed in recent years. Generically, these leptoquarks yield new sources of CP violation. In this paper, we explore constraints and discovery potential for electric dipole moments (EDMs) in leptonic and hadronic systems. We provide the most generic expressions for dipole moments induced by vector leptoquarks at one loop. We find that $O(1)$ CP-violating phases in tau and muon couplings can lead to corresponding EDMs within reach of next-generation EDM experiments, and that existing bounds on the electron EDM already put stringent constraints on CP-violating electron couplings.

    hep-phJHEP(2020)·41 citations
14. 14*

    Model independent study for the anomalous $W^{+}{W}^{-}\gamma$ couplings at the future lepton-hadron colliders

    S. Spor🇹🇷 · A. A. Billur🇹🇷 · M. Köksal🇹🇷

    The triple gauge couplings are completely defined by the non-Abelian gauge nature of the Standard Model, precision measurements of these couplings at the present and future colliders in this way provide a substantial opportunity to test the gauge structure of the Standard Model. Also, measurements of these couplings are sensitive to new physics beyond the Standard Model. In this context, these couplings can be described by an effective Lagrangian. Here, we have studied the potential of the future $\mu p$ colliders on the anomalous $WW\gamma$ interactions via the subprocess ${\gamma }^{\ast }p\to W^{-}{\nu }_{\mu }$. This subprocess has been generated through the main process $\mu p\to \mu {\gamma }^{\ast }p\to W^{-}{\nu }_{\mu }p$ at the LHC-$\mu p$, the FCC-$\mu p$ and the SPPC-$\mu p$. For these reasons, the total cross sections have been obtained as a function of the anomalous $WW\gamma$ couplings. Also, we have been calculated the best constraints on $c_{WWW}$, $c_W$ and $c_B$ parameters that define the anomalous $WW\gamma$ interactions.

    hep-phEur.Phys.J.Plus(2020)·8 citations
15. 15*

    Chiral pasta

    Andreas Schmitt🇬🇧

    Interiors of neutron stars are ultra-dense and may contain a core of deconfined quark matter. Such a core connects to the outer layers smoothly or through a sharp microscopic interface or through an intermediate macroscopic layer of inhomogeneous mixed phases, which is globally neutral but locally contains electrically charged domains. Here I employ a nucleon-meson model under neutron star conditions that shows a first-order chiral phase transition at large densities. In the vicinity of this chiral transition I calculate the free energies of various mixed phases - different 'pasta structures' - in the Wigner-Seitz approximation. Crucially, chirally broken nuclear matter and the approximately chirally symmetric phase (loosely interpreted as quark matter) are treated on the same footing. This allows me to compute the interface profiles of bubbles, rods, and slabs fully consistently, taking into account electromagnetic screening effects and without needing the surface tension as an input. I find that the full numerical results tend to disfavor mixed phases compared to a simple step-like approximation used frequently in the literature and that the predominantly favored pasta structure consists of slabs with a surface tension $\Sigma \simeq 6\mathrm{MeV}/{\mathrm{fm}}^2$.

    hep-phastro-ph.HEnucl-thPRD(2020)·28 citations
16. 16*

    Gluon-Photon Signatures for color octet at the LHC (and beyond)

    G. Cacciapaglia🇫🇷 · A. Deandrea🇫🇷 · T. Flacke🇰🇷 · A. M. Iyer🇫🇷

    We consider a color octet scalar particle and its exotic decay in the channel gluon-$\gamma$ using an effective Lagrangian description for its strong and electromagnetic interactions. Such a state is present in many extensions of the Standard Model, and in particular in composite Higgs models with top partial compositeness, where couplings to photons arise via the Wess-Zumino-Witten term. We find that final states with one or two photons allow for a better reach at the LHC, even for small branching ratios. Masses up to $1.2$ TeV can be probed at the HL-LHC by use of all final states. Finally, we estimate the sensitivity of the hadronic FCC.

    hep-phJHEP(2020)·39 citations
17. 17*

    Probing new neutral gauge bosons with CEvNS and neutrino-electron scattering

    Omar G. Miranda🇲🇽 · Dimitrios K. Papoulias🇪🇸 · Mariam Tórtola🇪🇸 · José W. F. Valle🇪🇸

    The potential for probing extra neutral gauge boson mediators ($Z^{\prime }$) from low-energy measurements is comprehensively explored. Our study mainly focuses on $Z^{\prime }$ mediators present in string-inspired $E_6$ models and left-right symmetry. We estimate the sensitivities of coherent-elastic neutrino-nucleus scattering (CE$\nu$NS) and neutrino-electron scattering experiments. Our results indicate that such low-energy high-intensity measurements can provide a valuable probe, complementary to high-energy collider searches and electroweak precision measurements.

    hep-phPRD(2020)·36 citations
18. 18*

    Probing approach of the Parton-Hadron-String Dynamics in production for K${}_S$ mesons

    O. Kot🇺🇦 · T. Obikhod🇺🇦 · O. Okhrimenko🇺🇦 · I. Petrenko🇺🇦

    Heavy ion collisions provide a unique probe of the quark-gluon plasma properties. The role of partonic degrees of freedom in p-Pb collisions at $\sqrt{s_{NN}}$ = 5 TeV by studying the production cross section is studied. Experimental observable like the number of K${}_S$ mesons is sensitive to the kinematic properties of the reaction. Our results demonstrate the importance of angular distribution for the partonic degrees of freedom in hadronization process.

    hep-phnucl-th0 citations
19. 19*

    Large-$N_c$ analysis of magnetic and axial two-nucleon currents in pionless effective field theory

    Thomas R. Richardson🇺🇸 · Matthias R. Schindler🇺🇸

    We analyze magnetic and axial two-nucleon contact terms in a combined large-$N_c$ and pionless effective field theory expansion. These terms play important roles in correctly describing, e.g., the low-energy cross section of radiative neutron capture and the deuteron magnetic moment. We show that the large-$N_c$ expansion hints towards a hierarchy between the two leading-order magnetic terms that matches that found in phenomenological fits. We also comment on the issue of naturalness in different Lagrangian bases.

    ↳ nucl-thhep-phPRC(2020)·10 citations
20. 20*

    Asymptotically flat, parameterized black hole metric preserving Kerr symmetries

    Zack Carson🇺🇸 · Kent Yagi🇺🇸

    Recently the Event Horizon Telescope Collaboration, with very-long baseline interferometric observations, resolved structure at the scale of $\sim 5$ Schwarzschild radii about the center of M87${}^{\ast }$, the supermassive black hole resident at the center of Messier 87. This important observation has paved the way for testing what is known as the "no-hair" theorem, stating that isolated black holes are described by the Kerr metric, parameterized only by their mass and spin. Generic, parameterized spacetimes beyond Kerr allow one to arbitrarily test the no-hair theorem for deviations from the Kerr result with no prior theoretical knowledge or motivation. In this paper, we present such a new general, stationary, axisymmetric and asymptotically flat black hole solution with separable geodesic equations (thus preserving symmetries of a Kerr black hole), extending the previous work of Johannsen. In this new metric, five free non-linear functions parameterically deviate from the Kerr result, allowing one to effectively transform to many alternative black hole solutions present in the literature. We then derive analytic expressions for the Keplerian and epicyclic frequencies, the orbital energy and angular momentum, and the location of the innermost stable orbit of circular equatorial particle orbits. We also compute the image of the photon rings in the new spacetime, which correspond to the boundary of the black hole shadow image taken by the Event Horizon Telescope. We finally compare each quantity for the Kerr result against various parameterizations of the metric, finding that, especially for highly rotating black holes, the two solutions disagree significantly. Such a metric parameterization allows one to perform the no-hair tests in a model-independent way, and finally map constraints to specific alternative theories of gravity.

    ↳ gr-qchep-phPRD(2020)·67 citations
21. 21*

    Quantum nature of Wigner function for inflationary tensor perturbations

    Jinn-Ouk Gong🇰🇷 · Min-Seok Seo🇰🇷

    We study the Wigner function for the inflationary tensor perturbation defined in the real phase space. We compute explicitly the Wigner function including the contributions from the cubic self-interaction Hamiltonian of tensor perturbations. Then we argue that it is no longer an appropriate description for the probability distribution in the sense that quantum nature allows negativity around vanishing phase variables. This comes from the non-Gaussian wavefunction in the mixed state as a result of the non-linear interaction between super- and sub-horizon modes. We also show that this is related to the explicit infrared divergence in the Wigner function, in contrast to the trace of the density matrix.

    ↳ hep-thastro-ph.COgr-qchep-ph+1JHEP(2020)·8 citations
22. 22*

    First-order phase boundaries of the massive 1+1 dimensional Nambu--Jona-Lasinio model with isospin

    Michael Thies🇩🇪

    The massive two-dimensional Nambu--Jona-Lasinio model with isospin (isoNJL) is reconsidered in the large $N_c$ limit. We continue the exploration of its phase diagram by constructing missing first-order phase boundaries. At zero temperature, a phase boundary in the plane of baryon and isospin chemical potentials separates the vacuum from a crystal phase. We derive it from the baryon spectrum of the isoNJL model which, in turn, is obtained via a numerical Hartree-Fock (HF) calculation. At finite temperature, a first-order phase boundary sheet is found using a thermal HF calculation. It interpolates smoothly between the zero temperature phase boundary and the perturbative sheet. The calculations remain tractable owing to the assumption that the charged pion condensate vanishes. In that case, most of the calculations can be done with methods developed in the past for solving the massive one-flavor NJL model.

    ↳ hep-thhep-lathep-phPRD(2020)·10 citations
23. 23*

    Beyond the standard model with six-dimensional spinors

    David Chester🇺🇸 · Michael Rios🇺🇸 · Alessio Marrani🇮🇹

    6D spinors with $Spin(3,3)$ symmetry are utilized to efficiently encode three generations of matter. $E_{8(-24)}$ is shown to contain physically relevant subgroups with representations for GUT groups, spacetime symmetries, three generations of the standard model fermions, and Higgs bosons. Pati-Salam, $SU(5)$, and $Spin(10)$ grand unified theories are found when a single generation is isolated. For spacetime symmetries, $Spin(4,2)$ may be used for conformal symmetry, $Ad{S}_5\to d{S}_4$, or simply broken to $Spin(3,1)$ of Minkowski space. Another class of representations finds $Spin(2,2)$ and can give $Ad{S}_3$ with various GUTs. An action for three generations of fermions in the Majorana-Weyl spinor $128$ of $Spin(4,12)$ is found with $Spin(3)$ flavor symmetry inside $E_{8(-24)}$. The $128$ of $Spin(4,12)$ can be regarded as the tangent space to a particular pseudo-Riemannian form of the octo-octonionic Rosenfeld projective plane $E_{8(-24)}/Spin(4,12)=({\mathbb{O}}_s\times \mathbb{O}){\mathbb{P}}^2$.

    ↳ physics.gen-phhep-phhep-thParticles(2023)·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.