Tue·Feb 19, 2019Tuesday·February 19, 2019

1. 01*

   Scotogenic dark matter stability from gauged matter parity

   Sin Kyu Kang🇰🇷 · Oleg Popov🇰🇷 · Rahul Srivastava🇪🇸 · José W. F. Valle🇪🇸 · Carlos A. Vaquera-Araujo🇲🇽

   We explore the idea that dark matter stability results from the presence of a matter-parity symmetry, arising naturally as a consequence of the spontaneous breaking of an extended $\mathrm{SU}(3)\otimes \mathrm{SU}(3{)}_{\mathrm{L}}\otimes \mathrm{U}(1{)}_{\mathrm{X}}\otimes \mathrm{U}(1{)}_{\mathrm{N}}$ electroweak gauge symmetry with fully gauged B-L. Using this framework we construct a theory for scotogenic dark matter and analyze its main features.

   hep-phPLB(2019)·35 citations
2. 02*

   A new approach to gauge coupling unification and proton decay

   Stefan Pokorski🇵🇱 · Krzysztof Rolbiecki🇵🇱 · Graham G. Ross🇬🇧 · Kazuki Sakurai🇵🇱

   An analytical formalism, including RG running at two loop order, is used to link the supersymmetric and GUT spectra in any GUT model in which the three gauge couplings unify. In each specific GUT model, one can then fully explore the interplay between the pattern of supersymmetry breaking and the prediction for the proton lifetime. With this formalism at hand, we study three concrete GUT models: (i) Minimal SU(5) SUSY GUT, (ii) Missing Partner SU(5) SUSY GUT, and (iii) an orbifold SU(5) SUSY GUT. In each case we derive interesting conclusions about the possible patterns of the supersymmetric spectrum once the present limits on the proton lifetime are imposed, and vice versa, we obtain the predictions for the proton lifetime for specific viable choices of the SUSY spectrum.

   hep-phJHEP(2019)·14 citations
3. 03*

   On DUNE prospects in the search for sterile neutrinos

   Igor Krasnov🇷🇺

   Experiments measuring the parameters of active neutrino oscillations can also search for the sterile neutrinos in a part of sterile neutrino parameter space. In this paper, we analyze the prospects for the sterile neutrino search in the upcoming experiment DUNE for the sterile neutrinos with masses at GeV scale. As it relies on the still-undecided design of the Near Detector, we provide the expected number of the sterile neutrino decays in the Near Detector volume. Our most optimistic predictions show that the corresponding limit on mixing can be approximately of the same order as the previous estimates made for the LBNE. We present our results as separate plots for the sterile neutrino mixing with electron, muon and tau neutrinos. Generally, DUNE has good prospects to probe large region of the previously unavailable part of the parameter space before the new projects (like SHiP) join the searches.

   hep-phPRD(2019)·61 citations
4. 04*

   $b\to s{\mu }^{+}{\mu }^{-}$ anomalies and related phenomenology in $U(1{)}_{B_3-x_{\mu }{L}_{\mu }-x_{\tau }{L}_{\tau }}$ flavor gauge models

   P. Ko🇰🇷 · Takaaki Nomura🇰🇷 · Chaehyun Yu🇰🇷

   We propose a generation dependent lepton/baryon gauge symmetry, $U(1{)}_{B_3-x_{\mu }{L}_{\mu }-x_{\tau }{L}_{\tau }}\equiv U(1{)}_X$ (with $x_{\mu }+x_{\tau }=1$ for anomaly cancellation), as a possible solution for the $b\to s{\mu }^{+}{\mu }^{-}$ anomalies. By introducing two Higgs doublet fields, we can reproduce the observed CKM matrix, and generate flavor changing $Z^{\prime }$ interactions in the quark sector. Thus one can explain observed anomalies in $b\to s{\ell }^{+}{\ell }^{-}$ decay with the lepton non-universal $U(1{)}_X$ charge assignments. We show the minimal setup explaining $b\to s{\ell }^{+}{\ell }^{-}$ anomalies, neutrino masses and mixings and dark matter candidate, taking into account experimental constraints of flavor physics such as charged lepton flavor violations and the $B_s$--${\bar{B}}_s$ mixing. Finally we discuss collider physics focusing on $Z^{\prime }$ production at the Large Hadron Collider and relic density of our dark matter candidate.

   hep-phhep-exJHEP(2019)·24 citations
5. 05*

   Revisiting the Heavy Vector Quarkonium Leptonic Widths

   Guo-Li Wang🇨🇳 · Xing-Gang Wu🇨🇳

   We revisit the heavy quarkonium leptonic decays $\psi (nS)\to {\ell }^{+}{\ell }^{-}$ and ${\rm Y}(nS)\to {\ell }^{+}{\ell }^{-}$ using the Bethe-Salpeter method. The emphasis is on the relativistic correction. For the $\psi (1S-5S)$ decays, the relativistic effects are $22_{-2}^{+3}\%$, $34_{-5}^{+5}\%$, $41_{-6}^{+6}\%$, $52_{-13}^{+11}\%$ and $62_{-12}^{+14}\%$, respectively. For the ${\rm Y}(1S-5S)$ decays, the relativistic effects are $14_{-2}^{+1}\%$, $23_{-3}^{+0}\%$, $20_{-2}^{+8}\%$, $21_{-7}^{+6}\%$ and $28_{-7}^{+2}\%$, respectively. Thus, the relativistic corrections are large and important in heavy quarkonium leptonic decays, especially for the highly excited charmonium. Our results for ${\rm Y}(nS)\to {\ell }^{+}{\ell }^{-}$ are consistent with the experimental data.

   hep-phhep-exCPC(2020)·15 citations
6. 06*

   Asymmetries of anti-triplet charmed baryon decays

   C.Q. Geng🇨🇳 · Chia-Wei Liu🇹🇼 · Tien-Hsueh Tsai🇹🇼

   We analyze the decay processes of ${\mathbf{B}}_c\to {\mathbf{B}}_{n}M$ with the $SU(3{)}_F$ flavor symmetry and spin-dependent amplitudes, where ${\mathbf{B}}_c({\mathbf{B}}_n)$ and $M$ are the anti-triplet charmed (octet) baryon and nonet meson states, respectively. In the $SU(3{)}_F$ approach, it is the first time that the decay rates and up-down asymmetries are fully and systematically studied without neglecting the $\mathcal{O}(\overline{15})$ contributions of the color anti-symmetric parts in the effective Hamiltonian. Our results of the up-down asymmetries based on $SU(3{)}_F$ are quite different from the previous theoretical values in the literature. In particular, we find that the up-down symmetry of $\alpha ({\Lambda }_c^{+}\to {\Xi }^0{K}^{+}{)}_{SU(3)}=0.94_{-0.11}^{+0.06}$, which is consistent with the recent experimental data of $0.77\pm 0.78$ by the BESIII Collaboration, but predicted to be zero in the literature. We also examine the $K_S^0-K_L^0$ asymmetries between the decays of ${\mathbf{B}}_c\to {\mathbf{B}}_n{K}_S^0$ and ${\mathbf{B}}_c\to {\mathbf{B}}_n{K}_L^0$ with both Cabibbo-allowed and doubly Cabibbo-suppressed transitions.

   hep-phhep-exPLB(2019)·70 citations
7. 07*

   An inverse seesaw model with global $U(1{)}_H$ symmetry

   Ujjal Kumar Dey🇰🇷 · Takaaki Nomura🇰🇷 · Hiroshi Okada🇰🇷

   We propose an inverse seesaw model based on hidden global symmetry $U(1{)}_H$ in which we realize tiny neutrino masses with rather natural manner taking into account relevant experimental bounds. The small Majorana mass for inverse seesaw mechanism is induced via small vacuum expectation value of a triplet scalar field whose Yukawa interactions with standard model fermions are controlled by $U(1{)}_H$. We discuss the phenomenology of the exotic particles present in the model including the Goldstone boson coming from breaking of the global symmetry, and explore testability at the Large Hadron Collider experiments.

   hep-phPRD(2019)·7 citations
8. 08*

   Sensitivity of the intensity frontier experiments for neutrino and scalar portals: analytic estimates

   Kyrylo Bondarenko🇳🇱 · Alexey Boyarsky🇳🇱 · Maksym Ovchynnikov🇳🇱 · Oleg Ruchayskiy🇩🇰

   In recent years, a number of intensity-frontier experiments have been proposed to search for feebly interacting particles with a mass in the GeV range. We show analytically how the characteristic shape of the sensitivity regions of such experiments - upper and lower boundaries of the probed region, the maximal mass reach - depends on the parameters of the experiments, taking the SHiP and the MATHUSLA experiments as an example. We find a good agreement of our estimates with the results of the Monte Carlo simulations.

   hep-phhep-exJHEP(2019)·35 citations
9. 09*

   Gravitational Searches for Lorentz Violation with Ultracold Neutrons

   C. A. Escobar🇲🇽 · A. Martín-Ruiz🇲🇽

   We investigate the consequences of Lorentz violation (as expressed within the gravity sector of the Standard-Model Extension) for gravitational quantum states of ultracold neutrons (UCNs). Since our main aim is to compare our theoretical results with the recent high-sensitivity GRANIT experiment, we frame this work according to the laboratory conditions under which it was carried out. This offers the possibility of testing Lorentz invariance by experiments using UCNs. Thus we consider the nonrelativistic Hamiltonian describing the quantum mechanics of an unpolarized neutron's beam in presence of a weak-gravity field, and the latter is described by a post-Newtonian expansion of the metric up to order $O(2)$ and linear in the Lorentz-violating coefficients ${\bar{s}}^{\mu \nu }$. Using a semi-classical wave packet, which is appropriate to describe an intense beam of UCNs, we derive the effective Hamiltonian describing the neutron's motion along the axis of free fall and then we compute the Lorentz-violating shifts on the energy levels. The comparison of our results with those obtained in the GRANIT experiment leads to an upper bound for a particular combination of the Lorentz-violating coefficients.

   hep-phhep-thPRD(2019)·15 citations
10. 10*

    Analysis of the ${\mathbf{e}}^{+}{\mathbf{e}}^{-}\to \mathbf{J}/\mathbf{\psi D}\bar{\mathbf{D}}$ reaction close to the threshold concerning claims of a ${\chi }_{c0}(2P)$ state

    En Wang🇨🇳 · Wei-Hong Liang🇨🇳 · Eulogio Oset🇪🇸

    We analyze the $D\bar{D}$ mass distribution from a recent Belle experiment on the $e^{+}{e}^{-}\to J/\psi D\bar{D}$ reaction, and show that the mass distribution divided by phase space does not have a clear peak above the $D\bar{D}$ threshold that justifies the experimental claim of a ${\chi }_{c0}(2P)$ state from those data. Then we use a unitary formalism with coupled channels $D^{+}{D}^{-}$, $D^0{\bar{D}}^0$, $D_s{\bar{D}}_s$, and $\eta \eta$, with some of the interactions taken from a theoretical model, and use the data to fix other parameters. We then show that, given the poor quality of the data, we can get different fits leading to very different $D\bar{D}$ amplitudes, some of them supporting a $D\bar{D}$ bound state and others not. The main conclusion is that the claim for the ${\chi }_{c0}(2P)$ state, already included in the PDG, is premature, but refined data can provide very valuable information on the $D\bar{D}$ scattering amplitude. As side effects, we warn about the use of a Breit-Wigner amplitude parameterization close to threshold, and show that the $D_s{\bar{D}}_s$ channel plays an important role in this reaction.

    hep-phhep-exEPJA(2021)·33 citations
11. 11*

    Explicit form of the R-ratio of electron-positron annihilation into hadrons

    A.V.Nesterenko🇷🇺

    The explicit expression for the R-ratio of electron-positron annihilation into hadrons, which properly accounts for all the effects due to continuation of the spacelike perturbative results into the timelike domain, is obtained at an arbitrary loop level. Several equivalent ways to derive a commonly employed approximation of the R-ratio are recapped and the impact of discarded in the latter higher-order pi2-terms on the evaluation of the strong running coupling is elucidated. The obtained results substantially facilitate the theoretical study of electron-positron annihilation into hadrons and the related strong interaction processes.

    hep-phhep-exJ.Phys.G(2019)·15 citations
12. 12*

    Relativistic Quantum Kinetic Theory for Massive Fermions and Spin Effects

    Jian-Hua Gao🇨🇳 · Zuo-Tang Liang🇨🇳

    We present the complete first order relativistic quantum kinetic theory with spin for massive fermions derived from the Wigner function formalism in a concise form that shows explicitly how the 32 Wigner equations reduce to 4 independent transport equations. We solve modified on-shell conditions to obtain the general solution and present the corresponding transport equations in three different forms that are suitable for different purposes. We demonstrate how different spin effects arise from the kinetic theory by calculating the chiral separation effect with mass correction, the chiral anomaly from the axial current and the quantum magnetic moment density induced by vorticity and magnetic field. We also show how to generate the global polarization effect due to spin vorticity coupling. The formalism presented may serve as a practical theoretical framework to study different spin effects in relativistic fermion systems encountered in different areas such as heavy ion, astro-particle and condensed matter physics as well.

    hep-phhep-thnucl-thPRD(2019)·160 citations
13. 13*

    Kinetic theory for massive spin-1/2 particles from the Wigner-function formalism

    Nora Weickgenannt🇩🇪 · Xin-li Sheng🇨🇳 · Enrico Speranza🇩🇪 · Qun Wang🇨🇳 · Dirk H. Rischke🇩🇪

    We calculate the Wigner function for massive spin-1/2 particles in an inhomogeneous electromagnetic field to leading order in the Planck constant $\hslash$. Going beyond leading order in $\hslash$ we then derive a generalized Boltzmann equation in which the force exerted by an inhomogeneous electromagnetic field on the particle dipole moment arises naturally. Carefully taking the massless limit we find agreement with previous results. The case of global equilibrium with rotation is also studied. Finally, we outline the derivation of fluid-dynamical equations from the components of the Wigner function. The conservation of total angular momentum is promoted as an additional fluid-dynamical equation of motion. Our framework can be used to study polarization effects induced by vorticity and magnetic field in relativistic heavy-ion collisions.

    hep-phPRD(2019)·243 citations
14. 14*

    Round Table on Axions and Axion-like Particles

    Paolo Di Vecchia🇩🇰 · Maurizio Giannotti🇺🇸 · Massimiliano Lattanzi🇮🇹 · Axel Lindner🇩🇪

    In this contribution, based on the discussion at a round table of the XIII Quark Confinement and the Hadron Spectrum - Confinement conference, we review the main properties of the QCD axion and, more generally, of axion-like particles and their relevance in astrophysics and cosmology. In the last section we describe the experimental concepts to search for the QCD axion and axion-like particles (ALPs).

    hep-phastro-ph.COPoS(2019)·31 citations
15. 15*

    Probing the Scale of New Physics in the $ZZ\gamma$ Coupling at $e^{+}{e}^{-}$ Colliders

    John Ellis🇬🇧 · Shao-Feng Ge🇯🇵 · Hong-Jian He🇨🇳 · Rui-Qing Xiao🇨🇳

    The $ZZ\gamma$ triple neutral gauge couplings are absent in the Standard Model (SM) at the tree level. They receive no contributions from dimension-6 effective operators, but can arise from effective operators of dimension-8. We study the scale of new physics associated with such dimension-8 operators that can be probed by measuring the reaction $e^{+}{e}^{-}\to Z\gamma$, followed by $Z\to \ell \bar{\ell },\nu \bar{\nu }$ decays, at future $e^{+}{e}^{-}$ colliders including the ILC, CEPC, FCC-ee and CLIC. We demonstrate how angular distributions of the final state mono-photon and leptons can play a key role in suppressing SM backgrounds. We further show that using electron/positron beam polarizations can significantly improve the signal sensitivities. We find that the dimension-8 new physics scale can be probed up to the multi-TeV region at such lepton colliders.

    hep-phhep-exCPC(2020)·90 citations
16. 16*

    Non-linear evolution in QCD at high-energy beyond leading order

    B. Ducloué🇫🇷 · E. Iancu🇫🇷 · A.H. Mueller🇺🇸 · G. Soyez🇫🇷 · D.N. Triantafyllopoulos🇮🇹

    The next-to-leading order (NLO) Balitsky-Kovchegov (BK) equation describing the high-energy evolution of the scattering between a dilute projectile and a dense target suffers from instabilities unless it is supplemented by a proper resummation of the radiative corrections enhanced by (anti-)collinear logarithms. Earlier studies have shown that if one expresses the evolution in terms of the rapidity of the dilute projectile, the dominant anti-collinear contributions can be resummed to all orders. However, in applications to physics, the results must be re-expressed in terms of the rapidity of the dense target. We show that although they lead to stable evolution equations, resummations expressed in the rapidity of the dilute projectile show a strong, unwanted, scheme dependence when their results are translated in terms of the target rapidity. Instead, in this paper, we work directly in the rapidity of the dense target where anti-collinear contributions are absent but where new, collinear, instabilities arise. These are milder since disfavoured by the typical BK evolution. We propose several prescriptions for resumming these new double logarithms and find only little scheme dependence. The resummed equations are non-local in rapidity and can be extended to full NLO accuracy.

    hep-phJHEP(2019)·133 citations
17. 17*

    Low-energy lepton physics in the MRSSM: $(g-2{)}_{\mu }$, $\mu \to e\gamma$ and $\mu \to e$ conversion

    Wojciech Kotlarski🇩🇪 · Dominik Stöckinger🇩🇪 · Hyejung Stöckinger-Kim🇩🇪

    Low-energy lepton observables are discussed in the Minimal R-symmetric Supersymmetric Standard Model. We present comprehensive numerical analyses and the analytic one-loop results for $(g-2{)}_{\mu }$, $\mu \to e\gamma$, and $\mu \to e$ conversion. The interplay between the three observables is investigated as well as the parameter regions with large $g-2$. A striking difference to the MSSM is the absence of $\tan \beta$ enhancements; however we find smaller enhancements governed by MRSSM-specific R-Higgsino couplings ${\lambda }_d$ and ${\Lambda }_d$. As a result we find significant contributions to $g-2$ only in a small parameter space with several SUSY masses below $200$ GeV, compressed spectra and large ${\lambda }_d$, ${\Lambda }_d$. In this parameter space there is a correlation between all three considered observables. In the parameter region with small $(g-2{)}_{\mu }$ the SUSY masses can be larger and the correlation between $\mu \to e\gamma$ and $\mu \to e$ conversion is weak. Therefore already COMET Phase 1 has a promising sensitivity to the MRSSM.

    hep-phJHEP(2019)·27 citations
18. 18*

    Lattice-based equation of state at finite baryon number, electric charge and strangeness chemical potentials

    J. Noronha-Hostler🇺🇸 · P. Parotto🇺🇸 · C. Ratti🇺🇸 · J. M. Stafford🇺🇸

    We construct an equation of state for Quantum Chromodynamics (QCD) at finite temperature and chemical potentials for baryon number $B$, electric charge $Q$ and strangeness $S$. We use the Taylor expansion method, up to the fourth power for the chemical potentials. This requires the knowledge of all diagonal and non-diagonal $BQS$ correlators up to fourth order: these results recently became available from lattice QCD simulations, albeit only at a finite lattice spacing $N_t=12$. We smoothly merge these results to the Hadron Resonance Gas (HRG) model, to be able to reach temperatures as low as 30 MeV; in the high temperature regime, we impose a smooth approach to the Stefan-Boltzmann limit. We provide a parameterization for each one of these $BQS$ correlators as functions of the temperature. We then calculate pressure, energy density, entropy density, baryonic, strangeness, electric charge densities and compare the two cases of strangeness neutrality and ${\mu }_S={\mu }_Q=0$. We also calculate the isentropic trajectories and compare them in the two cases. Our equation of state can be readily used as an input of hydrodynamical simulations of matter created at the Relativistic Heavy Ion Collider (RHIC).

    hep-phnucl-thPRC(2019)·97 citations
19. 19*

    Standard Model Effective Field Theory from On-shell Amplitudes

    Teng Ma🇨🇳 · Jing Shu🇨🇳 · Ming-Lei Xiao🇨🇳

    We present a general method of constructing unfactorizable on-shell amplitudes (amplitude basis), and build up their one-to-one correspondence to the independent and complete operator basis in effective field theory (EFT). We apply our method to the Standard Model EFT, and identify the amplitude basis in dimension 5 and 6, which correspond to the Weinberg operator and operators in Warsaw basis except for some linear combinations.

    hep-phCPC(2023)·101 citations
20. 20*

    Constructing effective field theories via their harmonics

    Brian Henning🇨🇭 · Tom Melia🇯🇵

    We consider the construction of operator bases for massless, relativistic quantum field theories, and show this is equivalent to obtaining the harmonic modes of a physical manifold (the kinematic Grassmannian), upon which observables have support. This enables us to recast the approach of effective field theory (EFT) through the lens of harmonic analysis. We explicitly construct harmonics corresponding to low mass dimension EFT operators.

    hep-phhep-thPRD(2019)·67 citations
21. 21*

    Naturalness without new particles

    Anson Hook🇺🇸

    We demonstrate that the physics which resolves naturalness problems need not take the form of new particles and can sometimes manifest itself as higher dimensional operators. As a proof of principle, we present a simple model where the scale of new particles is parametrically separated from that estimated via naturalness arguments applied to self-quartic couplings. In this example, new particles appear far above the scale $m/\sqrt{\lambda }$, where $m$ is the mass of the particle and $\lambda$ is its self-quartic coupling. The shift symmetry responsible for resolving the naturalness problem involves higher dimensional operators rather than new particles.

    hep-phJHEP(2021)·11 citations
22. 22*

    Fermion Conformal Bootstrap in 4d

    Denis Karateev🇨🇭 · Petr Kravchuk🇺🇸 · Marco Serone🇮🇹 · Alessandro Vichi🇨🇭

    We apply numerical conformal bootstrap techniques to the four-point function of a Weyl spinor in 4d non-supersymmetric CFTs. We find universal bounds on operator dimensions and OPE coefficients, including bounds on operators in mixed symmetry representations of the Lorentz group, which were inaccessible in previous bootstrap studies. We find discontinuities in some of the bounds on operator dimensions, and we show that they arise due to a generic yet previously unobserved fake primary effect, which is related to the existence of poles in conformal blocks. We show that this effect is also responsible for similar discontinuities found in four-fermion bootstrap in 3d, as well as in the mixed-correlator analysis of the 3d Ising CFT. As an important byproduct of our work, we develop a practical technology for numerical approximation of general 4d conformal blocks.

    ↳ hep-thhep-lathep-phJHEP(2019)·63 citations
23. 23*

    Study of the $h\gamma Z$ coupling using $e^{+}{e}^{-}\to h\gamma$ at the ILC

    Yumi Aoki🇯🇵 · Keisuke Fujii🇯🇵 · Sunghoon Jung🇰🇷 · Junghwan Lee🇰🇷 · Junping Tian🇯🇵 · Hiroshi Yokoya🇰🇷

    We study the $e^{+}{e}^{-}\to h\gamma$ process at the International Linear Collider (ILC) to probe new physics in the $h\gamma Z$ coupling. The study is performed at a center of mass energy of 250 GeV and is based on the full simulation of the International Large Detector (ILD). The expected signal significance is found to be 0.53 $\sigma$ for an integrated luminosity of 2000 fb${}^{-1}$ in the case of the standard model. The corresponding 95 $\%$ confidence level upper limit for the signal cross section is 1.08 fb for left-handed beam polarization.

    ↳ hep-exhep-ph4 citations
24. 24*

    An in-medium chiral power counting for nuclear matter and some applications

    J.A. Oller🇪🇸

    We review on a chiral power counting for in-medium chiral perturbation theory with nucleons and pions as explicit degrees of freedom coupled to external sources. It allows for a systematic expansion including both local and pion-mediated inter-nucleon interactions. One can identify from this power counting classes of non-perturbative diagrams that require resummation. A non-perturbative method based on Unitary Chiral Perturbation Theory was also developed for performing those resummations. This power counting and non-perturbative techniques were firstly applied to calculate the pion self-energy, the pion-decay constants and the quark condensate in nuclear matter up-to-and-including next-to-leading order (NLO) contributions. The cancellation of the contributions at NLO to the pion self-energy and decay constants from in-medium nucleon-nucleon (NN) interactions was derived. Some NLO NN contributions survive for the quark condensate due to the quark-mass dependence of the pion mass. Next, we discuss the calculation of the energy density in the nuclear medium by employing the in-medium NN scattering amplitudes. For symmetric and neutron matter it reproduces in good agreement, and without fine tuning, calculations from realistic NN potentials with a model for the three-nucleon interaction. These results are applied to derive the equation of state (EOS) for neutron stars and obtain an upper limit for a neutron mass slightly above 2 solar masses. Our results also fulfill other constraints from the detection of the gravitational waves in the event GW170817, like the upper bound on the maximal mass of a neutron star and the allowed interval for the radius of a 1.4-solar-mass neutron star. The knowledge of the neutron-matter EOS is also employed to give an upper bound of the gravitational constant within the strong gravitational field of a 2 solar-mass neutron star.

    ↳ nucl-thhep-phJ.Phys.G(2019)·7 citations
25. 25*

    Search for Extra Scalars Produced in Association with Muon Pairs at the ILC

    Yan Wang🇨🇳 · Jenny List🇩🇪 · Mikael Berggren🇩🇪

    We study the search for an extra scalar $S$ boson produced in association with the $Z$ boson at the International Linear Collider (ILC). The study is performed at center-of-mass energies of 250 GeV and 500 GeV based on the full simulation of the International Large Detector (ILD). In order to be as model-independent as possible, the analysis uses the recoil technique, in particular with the $Z$ boson decaying into a pair of muons. As a result, exclusion cross-section limits are given in terms of a scale factor $k$ with respect to the Standard Model Higgs-strahlung process cross section. These predicted results, covering all possible searching regions of the extra scalars at the 250 GeV ILC and the 500 GeV ILC, can be interpreted independently of the decay modes of the $S$ boson.

    ↳ hep-exhep-ph5 citations
26. 26*

    IceCube Sterile Neutrino Searches

    B.J.P. Jones🇺🇸

    Anomalies in short baseline experiments have been interpreted as evidence for additional neutrino mass states with large mass splittings from the known, active flavors. This explanation mandates a corresponding signature in the muon neutrino disappearance channel, which has yet to be observed. Searches for muon neutrino disappearance at the IceCube neutrino telescope presently provide the strongest limits in the space of mixing angles for eV-scale sterile neutrinos. This proceeding for the Very Large Volume Neutrino Telescopes (VLVnT) Workshop summarizes the IceCube analyses that have searched for sterile neutrinos and describes ongoing work toward enhanced, high-statistics sterile neutrino searches.

    ↳ hep-exhep-phEPJ Web Conf.(2019)·10 citations
27. 27*

    Experimental searches for muon decays beyond the Standard Model

    Francesco Renga🇮🇹

    The study of muon properties and decays played a crucial role in the early years of particle physics and contributed over decades to build and consolidate the Standard Model. At present, searches for muon decays beyond the Standard Model are performed by exploiting intense beams of muons, and plans exist to upgrade the present facilities or build new ones, which would open new prospects for the quest of new physics in this sector. In this paper I review the present status of the search for muon decays beyond the Standard Model, with a special attention to the most conventional muon lepton flavor violation experiments, but also considering more exotic scenarios and future outlooks.

    ↳ hep-exhep-phphysics.ins-detRev.Phys.(2019)·18 citations
28. 28*

    Mean field and two-body nuclear effects in inclusive electron scattering on argon, carbon and titanium: the superscaling approach

    M. B. Barbaro🇮🇹 · J. A. Caballero🇪🇸 · A. De Pace🇮🇹 · T. W. Donnelly🇺🇸 · R. González-Jiménez🇪🇸 · G. D. Megias🇪🇸

    We compare the predictions of the SuSAv2 model including two-particle two-hole meson-exchange currents with the recent JLab data for inclusive electron scattering on three different targets (C, Ar and Ti). The agreement is very good over the full energy spectrum, with some discrepancy seen only in the deep inelastic region. The 2p2h response, peaked in the dip region between the quasielastic and $\Delta$-resonance peak, is essential to reproduce the data. We also analyze the $k_F$ (Fermi momentum) dependence of the data in terms of scaling of second kind, showing that the 2p2h response scales very differently from the quasielastic one, in full accord with what is predicted by the model. The results represent a valuable test of the applicability of the model to neutrino scattering processes on different nuclei.

    ↳ nucl-thhep-phPRC(2019)·25 citations
29. 29*

    Light front QED, Stueckelberg field and Infrared divergence

    T. R. Govindarajan🇮🇳 · Jai D. More🇮🇳 · P. Ramadevi🇮🇳

    Stueckelberg mechanism introduces a scalar field, known as Stueckelberg field, so that gauge symmetry is preserved in the massive abelian gauge theory. In this work, we show that the role of the Stueckelberg field is similar to the Kulish and Faddeev coherent state approach to handle infrared (IR) divergences. We expect that the light-front quantum electrodynamics (LFQED) with Stueckelberg field must be IR finite in the massless limit of the gauge boson. We have explicitly shown the cancellation of IR divergences in the relevant diagrams contributing to self-energy and vertex correction at leading order.

    ↳ hep-thhep-phMod.Phys.Lett.A(2019)·2 citations
30. 30*

    Transverse Ward-Takahashi Identities and Full Vertices Functions in Different Representation in QED${}_3$

    Cui-Bai Luo🇨🇳 · Hong-Shi Zong🇨🇳

    We first derive the transverse Ward-Takahashi identities (WTI) of 3-dimensional quantum electrodynamics (QED${}_3$) by means of the canonical quantization method and the path integration method, and then prove for the first time that QED${}_3$ is strictly solvable based on the transverse WTI and the longitudinal WTI, that is, the full vector and tensor vertices functions can be expressed in term of the fermion propagators in QED${}_3$. Further, we discuss the effect of different $\gamma$ matrix representations on the full fermion-boson vertex function. It is found that the full vector vertex function does not depend on the different $\gamma$ matrix representation we use, \textit{i.e.}, it does not depend on whether we use 4 $\times$ 4 representation or 2 $\times$ 2 representation. But the tensor vertex function depends on the representation we use.

    ↳ hep-thhep-phCPC(2020)·1 citation
31. 31*

    $d=4$ as the critical dimensionality of asymptotically safe interactions

    Astrid Eichhorn🇩🇰 · Marc Schiffer🇩🇪

    We explore the question why our universe is four dimensional from an asymptotically safe vantage point. We find hints that asymptotically safe quantum fluctuations of gravity can only solve the $U(1)$ Landau-pole problem in the Standard Model in four dimensions. This could single out the observed dimensionality of the universe as the critical dimensionality of asymptotically safe interactions.

    ↳ hep-thgr-qchep-phPLB(2019)·68 citations
32. 32*

    Interacting two-particle states in the symmetric phase of the chiral Nambu--Jona-Lasinio model

    A. Jakovac🇭🇺 · A. Patkos🇭🇺

    The renormalisation group flow of the chiral Nambu--Jona-Lasinio (NJL) model with one fermion flavor is mapped out in the symmetric phase with the help of the Functional Renormalisation Group (FRG) method using a physically motivated non-local trial effective action. The well-known infrared unstable strongly coupled fixed point characterized by a set of pointlike four-fermion couplings is reproduced. The Gaussian infrared end-point of the flow of the four-fermion couplings is now accompanied by non-zero limiting composite couplings characteristic for interacting two-particle states with finite energy and physical size. The negative interaction energy of the constituents is extracted as a function of the physical size of the composite object. This function reaches a minimum in the accessible range of physical sizes, mildly depending on the set of initial values of the couplings. The propagation of a two-particle state minimizing the interaction energy has a natural bound state interpretation.

    ↳ hep-thhep-phMod.Phys.Lett.A(2020)·8 citations
33. 33*

    No-go theorem for static boson stars with negative cosmological constants

    Yan Peng🇨🇳

    In a recent paper, Hod has proven no-go theorem for asymptotically flat static regular boson stars. In the present work, we extend discussions to the gravity with a negative cosmological constant. We consider a scalar field vanishing at infinity. In the asymptotically AdS background, we show that spherically symmetric regular boson stars cannot be constructed with self-gravitating static scalar fields, whose potential is positive semidefinite and increases with respect to its argument.

    ↳ gr-qchep-phhep-thNPB(2020)·5 citations
34. 34*

    String Landscape and Fermion Masses

    Stefano Andriolo🇨🇳 · Shing Yan Li🇨🇳 · S.-H. Henry Tye🇨🇳

    Besides the string scale, string theory has no parameter except some quantized flux values; and the string theory Landscape is generated by scanning over discrete values of all the flux parameters present. We propose that a typical (normalized) probability distribution $P(\mathcal{Q})$ of a physical quantity $\mathcal{Q}$ (with nonnegative dimension) tends to peak (diverge) at $\mathcal{Q}=0$ as a signature of string theory. In the Racetrack Kähler uplift model, where $P(\Lambda )$ of the cosmological constant $\Lambda$ peaks sharply at $\Lambda =0$, the electroweak scale (not the electroweak model) naturally emerges when the median $\Lambda$ is matched to the observed value. We check the robustness of this scenario. In a bottom-up approach, we find that the observed quark and charged lepton masses are consistent with the same probabilistic philosophy, with distribution $P(m)$ that diverges at $m=0$, with the same (or almost the same) degree of divergence. This suggests that the Standard Model has an underlying string theory description, and yields relations among the fermion masses, albeit in a probabilistic approach (very different from the usual sense). Along this line of reasoning, the normal hierarchy of neutrino masses is clearly preferred over the inverted hierarchy, and the sum of the neutrino masses is predicted to be $\sum m_{\nu }\simeq 0.0592$ eV, with an upper bound $\sum m_{\nu }<0.066$ eV. This illustrates a novel way string theory can be applied to particle physics phenomenology.

    ↳ hep-thhep-phPRD(2020)·9 citations
35. 35*

    Ultra-peripheral-collision studies in the fixed-target mode with the proton and lead LHC beams

    N. Yamanaka🇫🇷 · C. Hadjidakis🇫🇷 · D. Kikola🇵🇱 · J.P. Lansberg🇫🇷 · L. Massacrier🇫🇷 · M.G. Echevarria🇮🇹 · A. Kusina🇵🇱 · I. Schienbein🇫🇷 · J. Seixas🇵🇹 · H.S. Shao🇫🇷 · A. Signori🇺🇸 · B. Trzeciak🇳🇱 and 21 other authors

    We address the physics case related to the studies of ultra-peripheral pH, pPb, PbH, and PbPb collisions in the fixed-target mode at the LHC. In particular, we discuss how one can measure the gluon generalized parton distribution E_g(x,xi,t) in exclusive J/psi photoproduction with a transversely polarized hydrogen target.

    ↳ hep-exhep-phnucl-exnucl-thPoS(2019)·1 citation
36. 36*

    Anomalous Supersymmetry

    George Katsianis🇬🇧 · Ioannis Papadimitriou🇰🇷 · Kostas Skenderis🇬🇧 · Marika Taylor🇬🇧

    We show that supersymmetry is anomalous in $\mathcal{N}=1$ superconformal quantum field theories (SCFTs) with an anomalous R-symmetry. This anomaly was originally found in holographic SCFTs at strong coupling. Here we show that this anomaly is present in general and demonstrate it for the massless superconformal Wess-Zumino model via a one loop computation. The anomaly appears first in four-point functions of two supercurrents with either two R-currents or with an R-current and an energy momentum tensor. In fact, the Wess-Zumino consistency conditions together with the standard R-symmetry anomaly imply the existence of the anomaly. We outline the implications of this anomaly.

    ↳ hep-thhep-phPRL(2019)·25 citations
37. 37*

    Exotic compact object behavior in black hole analogues

    Carlos A. R. Herdeiro🇵🇹 · Nuno M. Santos🇵🇹

    Classical phenomenological aspects of acoustic perturbations on a draining bathtub geometry where a surface with reflectivity $\mathcal{R}$ is set at a small distance from the would-be acoustic horizon, which is excised, are addressed. Like most exotic compact objects featuring an ergoregion but not a horizon, this model is prone to instabilities when $|\mathcal{R}{|}^2\approx 1$. However, stability can be attained for sufficiently slow drains when $|\mathcal{R}{|}^2\lesssim 70\%$. It is shown that the superradiant scattering of acoustic waves is more effective when their frequency approaches one of the system's quasi-normal mode frequencies.

    ↳ gr-qcastro-ph.HEhep-phhep-th+1PRD(2019)·4 citations
38. 38*

    Importance of initial and final state effects for azimuthal correlations in p+Pb collisions

    Moritz Greif🇩🇪 · Carsten Greiner🇩🇪 · Björn Schenke🇺🇸 · Sören Schlichting🇺🇸 · Zhe Xu🇨🇳

    We study the influence and interplay of initial state and final state effects in the dynamics of small systems, focusing on azimuthal correlations at different multiplicities. To this end we introduce a new model, matching the classical Yang-Mills dynamics of pre-equilibrium gluon fields (IP-GLASMA) to a perturbative QCD based parton cascade for the final state evolution (BAMPS) on an event-by-event basis. Depending on multiplicity of the event, we see transverse momentum dependent signatures of the initial, but also the final state in azimuthal correlation observables, such as $v_2\left\{2PC\right\}(p_T)$. In low-multiplicity events, initial state correlations dominate for transverse momenta $p_T>2\mathrm{GeV}$, whereas in high-multiplicity events and at low momenta final state interactions dominate and initial state correlations strongly affect $v_2\left\{2PC\right\}(p_T)$ for $p_T>2\mathrm{GeV}$ as well as the $p_T$ integrated $v_2\left\{2PC\right\}$. Nearly half of the final pT integrated $v_2\left\{2PC\right\}$ is contributed by the initial state in low-multiplicity events, whereas in high-multiplicity the share is much less. Based on Ref. [1], we are now able to carry out a systematic multiplicity scan, probing the dynamics on the border of initial state dominated to final state dominated - but not yet hydrodynamic regime.

    ↳ nucl-thhep-phNPA(2019)·2 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.