Thu·Apr 23, 2020Thursday·April 23, 2020

1. 01*

   Non-linear Regge trajectories with AdS/QCD

   Miguel Angel Martin Contreras🇨🇱 · Alfredo Vega🇨🇱

   In this work, we consider a non-quadratic dilaton $\Phi (z)=(\kappa z{)}^{2-\alpha }$ in the context of the static soft wall model to describe the mass spectrum of a wide range of vector mesons from the light up to the heavy sectors. The effect of this non-quadratic approach is translated into non-linear Regge trajectories with the generic form $M^2=a(n+b{)}^{\nu }$. We apply this sort of fits for the isovector states of $\omega$, $\varphi$, $J/\psi$ and ${\rm Y}$ mesons and compare with the corresponding holographic duals. We also extend these ideas to the heavy-light sector by using the isovector set of parameters to extrapolate the proper values of $\kappa$ and $\alpha$ through the average constituent mass $\bar{m}$ for each mesonic specie considered. In the same direction, we address the description of possible non-$q\bar{q}$ candidates using $\bar{m}$ as a holographic threshold, associated with the structure of the exotic state, to define the values of $\kappa$ and $\alpha$. We study the ${\pi }_1$ mesons in the light sector, and the $Z_c$, $Y$ and $Z_b$ mesons in the heavy sector as possible exotic vector states. Finally, the RMS error for describing these twenty-seven states with fifteen parameters (four values for $\kappa$ and $\alpha$ respectively and seven values for $\bar{m}$) is $12.61\%$.

   hep-phhep-thPRD(2020)·44 citations
2. 02*

   Limits on $CP$-violating hadronic interactions and proton EDM from paramagnetic molecules

   V. V. Flambaum🇦🇺 · I. B. Samsonov🇦🇺 · H. B. Tran Tan🇦🇺

   Experiments with paramagnetic ground or metastable excited states of molecules (ThO, HfF${}^{+}$, YbF, YbOH, BaF, PbO, etc.) provide strong constraints on electron electric dipole moment (EDM) and coupling constant $C_{SP}$ of contact semileptonic interaction. We compute new contributions to $C_{SP}$ arising from the nucleon EDMs due to combined electric and magnetic electron-nucleon interaction. This allows us to improve limits from the experiments with paramagnetic molecules on the $CP$-violating parameters, such as the proton EDM, $|d_p|<1.1\times 10^{-23}e\cdot$cm, the QCD vacuum angle, $|\bar{\theta }|<1.4\times 10^{-8}$, as well as the quark chromo-EDMs and $\pi$-meson-nucleon couplings. Our results may also be used to search for the axion dark matter which produces oscillating $\bar{\theta }$.

   hep-phnucl-thphysics.atom-phJHEP(2020)·13 citations
3. 03*

   Continuous and Discrete Symmetries of Renormalization Group Equations for Neutrino Oscillations in Matter

   Shun Zhou🇨🇳

   Three-flavor neutrino oscillations in matter can be described by three effective neutrino masses ${\tilde{m}}_i^{}$ (for $i=1,2,3$) and the effective mixing matrix $V_{\alpha i}^{}$ (for $\alpha =e,\mu ,\tau$ and $i=1,2,3$). When the matter parameter $a\equiv 2\sqrt{2}{G}_{\mathrm{F}}^{}{N}_e^{}E$ is taken as an independent variable, a complete set of first-order ordinary differential equations for ${\tilde{m}}_i^2$ and $|V_{\alpha i}^{}{|}^2$ have been derived in the previous works. In the present paper, we point out that such a system of differential equations possesses both the continuous symmetries characterized by one-parameter Lie groups and the discrete symmetry associated with the permutations of three neutrino mass eigenstates. The implications of these symmetries for solving the differential equations and looking for differential invariants are discussed.

   hep-phmath-phmath.MPJ.Phys.G(2022)·6 citations
4. 04*

   Curvature and thermal corrections in tree-level CPT-Violating Leptogenesis

   Nick E. Mavromatos🇬🇧 · Sarben Sarkar🇬🇧

   In a model for leptogenesis based on spontaneous breaking of Lorentz and CPT symmetry [1-3], we examine the consistency of using the approximation of plane-wave solutions for a free spin-(1/2) Dirac (or Majorana) fermion field propagating in a Friedmann-Lemaitre-Robertson-Walker space time augmented with a cosmic time-dependent (or, equivalently, a temperature-dependent) Kalb-Ramond (KR) background. For the range of parameters relevant for leptogenesis, our analysis fully justifies the use of plane-wave solutions in our study of leptogenesis with Boltzmann equations; any corrections induced by space-time-curvature are negligible. We also elaborate further on how the lepton asymmetry is communicated to the Baryon sector. We demonstrate that the KR background (KRB) does not contribute to the anomaly equations that determine the baryon asymmetry a) through an explicit evaluation of a triangle Feynman graph and b) indirectly, on topological grounds, by identifying the KRB as torsion (in the effective string-inspired low energy gravitational field theory).

   hep-phgr-qchep-thEPJC(2020)·17 citations
5. 05*

   Revisiting the tensor $J^{PC}=2^{--}$ meson spectrum

   L. M. Abreu🇧🇷 · F. M. da Costa Júnior🇧🇷 · A. G. Favero🇨🇦

   This work is devoted to the discussion and characterization of the tensor $2^{-(-)}$ meson spectrum, by making use of the Coulomb gauge Hamiltonian approach to QCD, with the interactions being given by an improved confining potential and a transverse hyperfine interaction, whose kernel is a Yukawa-type potential. Our aim is to study the basic features of $2^{-(-)}$ mesons within an unified framework through the whole range of quark masses. We concentrate our investigation on predictions of expected but yet-unobserved ground states of unflavored light mesons and on charmonium and bottomonium states. The numerical results are compared with existing literature.

   hep-phPRD(2020)·11 citations
6. 06*

   Light Dark Photon Dark Matter from Inflation

   Yuichiro Nakai🇨🇳 · Ryo Namba🇨🇳 · Ziwei Wang🇨🇦

   We discuss the possibility of producing a light dark photon dark matter through a coupling between the dark photon field and the inflaton. The dark photon with a large wavelength is efficiently produced due to the inflaton motion during inflation and becomes non-relativistic before the time of matter-radiation equality. We compute the amount of production analytically. The correct relic abundance is realized with a dark photon mass extending down to $10^{-21}\mathrm{eV}$.

   hep-phastro-ph.COgr-qchep-thJHEP(2020)·73 citations
7. 07*

   Breaking Mirror Twin Color

   Brian Batell🇺🇸 · Wei Hu🇺🇸 · Christopher B. Verhaaren🇺🇸

   We investigate simple extensions of the Mirror Twin Higgs model in which the twin color gauge symmetry and the discrete $Z_2$ mirror symmetry are spontaneously broken. This is accomplished in a minimal way by introducing a single new colored triplet, sextet, or octet scalar field and its twin along with a suitable scalar potential. This spontaneous $Z_2$ breaking allows for a phenomenologically viable alignment of the electroweak vacuum, and leads to dramatic differences between the visible and mirror sectors with regard to the residual gauge symmetries at low energies, color confinement scales, and particle spectra. In particular, several of our models feature a remnant $SU(2)$ or $SO(3)$ twin color gauge symmetry with a very low confinement scale in comparison to ${\Lambda }_{\mathrm{QCD}}$. Furthermore, couplings between the colored scalar and matter provide a new dynamical source of twin fermion masses, and due to the mirror symmetry, these lead to a variety of correlated visible sector effects that can be probed through precision measurements and collider searches.

   hep-phJHEP(2020)·10 citations
8. 08*

   Sterile neutrino dark matter via coinciding resonances

   J. Ghiglieri🇫🇷 · M. Laine🇨🇭

   It has been proposed that two resonances could coincide in the early universe at temperatures $T\sim \mathrm{0.2...0.5}$ GeV: one between two nearly degenerate GeV-scale sterile neutrinos, producing a large lepton asymmetry through freeze-out and decays; another between medium-modified active neutrinos and keV-scale sterile neutrinos, converting the lepton asymmetry into dark matter. Making use of a framework which tracks three sterile neutrinos of both helicities as well as three separate lepton asymmetries, and scanning the parameter space of the GeV-scale species, we establish the degree of fine-tuning that is needed for realizing this scenario.

   hep-phJCAP(2020)·53 citations
9. 09*

   Boundary effects on constituent quark masses and on chiral susceptibility in a four-fermion interaction model

   L. M. Abreu🇧🇷 · E. B. S. Corrêa🇧🇷 · E. S. Nery🇧🇷

   In this work we investigate the finite-size effects on the phase structure of a two-flavor four-fermion interaction model with a flavor-mixing four-body interaction and in the presence of a magnetic background, taking into account different boundary conditions. We employ mean-field approximation and Schwinger's proper-time method in a toroidal topology with antiperiodic and periodic boundary conditions. The chiral susceptibility and constituent quark masses are studied under the change of the relevant parameters: size of compactified coordinates, temperature, chemical potential and magnetic field strength, within the different scenarios of boundary conditions and the value of flavor-mixing parameter. The findings suggest that the thermodynamic behavior of this system is strongly affected by the combined effects of relevant variables, depending on the range of their change, the value of flavor-mixing parameter and the choice of boundary conditions.

   hep-phPhysica A: Statistical Mechanics and its Applications(2021)·13 citations
10. 10*

    New term in effective field theory at fixed topology

    M. Kieburg🇦🇺 · M. Lauritzen🇩🇰 · B.T. Søgaard🇩🇰 · K. Splittorff🇩🇰

    A random matrix model for lattice QCD which takes into account the positive definite nature of the Wilson term is introduced. The corresponding effective theory for fixed index of the Wilson Dirac operator is derived to next to leading order. It reveals a new term proportional to the topological index of the Wilson Dirac operator and the lattice spacing. The new term appears naturally in a fixed index spurion analysis. The spurion approach reveals that the term is the first in a new family of such terms and that equivalent terms are relevant for the effective theory of continuum QCD.

    ↳ hep-latcond-mat.dis-nnhep-phhep-thPRD(2021)·0 citations
11. 11*

    Computing Nucleon Electric Dipole Moment from lattice QCD

    Taku Izubuchi🇺🇸 · Hiroshi Ohki🇯🇵 · Sergey Syritsyn🇺🇸

    Electric dipole moments (EDMs) of nucleons and nuclei are actively considered as direct evidence of the CP violation. Calculations of nucleon EDMs on lattice are required to connect the quark- and hadron- level effective CP violating interactions within QCD or other CP violating sources in new physics beyond the standard model. Among them, the theta-induced nucleon EDM, that is the only such renormalizable interaction, has widely been investigated on a lattice. In the report, we review recent developments of the lattice calculations of nucleon EDM induced QCD theta term.

    ↳ hep-lathep-phPoS(2020)·11 citations
12. 12*

    Light nuclei in the hadron resonance gas

    Benjamin Dönigus🇩🇪

    The description of the production of light (anti-)(hyper-)nuclei in a hadron resonance gas, or statistical-thermal model approach, has proven to be rather successful, despite the fact that the binding energies of these compound objects are small compared to the emitting fireball temperature. We summarise some recent developments and findings in this approach.

    ↳ nucl-thhep-phIJMPE(2020)·19 citations
13. 13*

    Extended search for sub-eV axion-like resonances via four-wave mixing with a quasi-parallel laser collider in a high-quality vacuum system

    Akihide Nobuhiro🇯🇵 · Yusuke Hirahara🇯🇵 · Kensuke Homma🇯🇵 · Yuri Kirita🇯🇵 · Takaya Ozaki🇯🇵 · Yoshihide Nakamiya🇯🇵 · Masaki Hashida🇯🇵 · Shunsuke Inoue🇯🇵 · Shuji Sakabe🇯🇵

    Resonance states of axion-like particles were searched for via four-wave mixing by focusing two-color pulsed lasers into a quasi-vacuum. A quasi-parallel collision system that allows probing of the sub-eV mass range was realized by focusing the combined laser fields with an off-axis parabolic mirror. A 0.10 mJ/34 fs Ti:Sapphire laser pulse and a 0.14 mJ/9 ns Nd:YAG laser pulse were spatiotemporally synchronized by sharing a common optical axis and focused into the vacuum system. No significant four-wave mixing signal was observed at the vacuum pressure of $3.7\times 10^{-5}$ Pa , thereby providing upper bounds on the coupling-mass relation by assuming exchanges of scalar and pseudoscalar fields at a 95 % confidence level in the mass range below 0.21 eV. For this search, the experimental setup was substantially upgraded so that optical components are compatible with the requirements of the high-quality vacuum system, hence enabling the pulse power to be increased. With the increased pulse power, a new kind of pressure-dependent background photons emerged in addition to the known atomic four-wave mixing process. This paper shows the pressure dependence of these background photons and how to handle them in the search.

    ↳ hep-exhep-phPTEP(2020)·17 citations
14. 14*

    Phase Transitions of Quintessential AdS Black Holes in M-theory/Superstring Inspired Models

    A. Belhaj🇲🇦 · A. El Balali🇲🇦 · W. El Hadri🇲🇦 · Y. Hassouni🇲🇦 · E. Torrente-Lujan🇪🇸

    We study $d$-dimensional $AdS$ black holes surrounded by Dark Energy (DE), embedded in $D$-dimensional M-theory/superstring inspired models having $Ad{S}_d\times {\mathbb{S}}^{d+k}$ space-time with $D=2d+k$. We focus on the thermodynamic Hawking-Page phase transitions of quintessential DE black hole solutions, whose microscopical origin is linked to $N$ coincident $(d-2)$-branes supposed to live in such $(2d+k)$-dimensional models. Interpreting the cosmological constant as the number of colors $\propto N^{\frac{d-1}{2}}$, we calculate various thermodynamical quantities in terms of brane number, entropy and DE contributions. Computing the chemical potential conjugated to the number of colors in the absence of DE, we show that a generic black hole is more stable for a larger number of branes for lower dimensions $d$.In the presence of DE, we find that the DE state parameter ${\omega }_q$ should take particular values, for $(D,d,k)$ models, providing a non trivial phase transition structure.

    ↳ hep-thgr-qchep-phInt.J.Mod.Phys.A(2021)·29 citations
15. 15*

    Probing Flavor Structure of Cosmic Ray $e^{\mp }$ Spectrum and Implications for Dark Matter Indirect Searches

    Shao-Feng Ge🇨🇳 · Hong-Jian He🇨🇳 · Yu-Chen Wang🇨🇳 · Qiang Yuan🇨🇳

    Measuring high energy cosmic ray electrons/positrons (CRE) provides important means for the dark matter (DM) indirect detection and for probing the nearby galactic sources. In this work, we perform a systematic analysis of the flavor structure of DM annihilations into charged leptons based on the cosmic ray CRE spectra measured by DAMPE, Fermi-LAT, AMS-02, and CALET experiments. We study the annihilations of possible TeV scale DM particles in a nearby subhalo, which is proposed to explain the possible peak-like structure of the DAMPE CRE data. We pay special attention to the possible non-resonant excess (besides the possible peak-like structure) and demonstrate that such non-resonant excess can mainly arise from the decay of muons produced by the DM annihilations in the subhalo. With these we study the flavor composition of the lepton final states from DM annihilations $\chi \chi \to e^{+}{e}^{-},{\mu }^{+}{\mu }^{-},{\tau }^{+}{\tau }^{-}$ by fitting the CRE data. We demonstrate that decays of the final states ${\mu }^{+}{\mu }^{-}$ and ${\tau }^{+}{\tau }^{-}$ can provide the non-resonant excess, while the peak excess arises from the $e^{+}{e}^{-}$ final state. We further analyze the constraints on the lepton flavor composition using the Fermi-LAT $\gamma$-ray measurements. We find that the flavor composition is consistent with the Fermi-LAT data at relatively low Galactic latitudes, while the fraction of the final state ${\tau }^{\pm }$ is severely bounded.

    ↳ astro-ph.HEastro-ph.COhep-exhep-phNPB(2020)·11 citations
16. 16*

    Centrifugal effects in N-Delta states

    J. A. Niskanen🇫🇮

    Recently it has been pointed out that in the two-baryon $N\Delta$ or $\Delta \Delta$ system the width of the state is greatly diminished due to the relative kinetic energy of the two baryons, since the internal energy of the particles, available for pionic decay, is smaller. For nonzero orbital angular momenta this effect becomes state dependent. Also the real part of the $N\Delta$ energy can get contribution from the centrifugal barrier leading to rotational series of diffuse states. Obviously, these states may have an interpretation as isospin one dibaryons. Direct and explicit calculations for this are presented with some details of the coupled state wave functions displayed. With finite expectation values of these repulsive effects it may be possible to define state dependent effective thresholds for $N\Delta$ states and these, in turn, can show resonant like behavior.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2020)·2 citations
17. 17*

    Gravitational wave constraints on the observable inflation

    Erwin H. Tanin🇺🇸 · Tommi Tenkanen🇺🇸

    Gravitational waves (GW) produced in the early Universe contribute to the number of relativistic degrees of freedom, $N_{\mathrm{eff}}$, during Big Bang Nucleosynthesis (BBN). By using the constraints on $N_{\mathrm{eff}}$, we present a new bound on how much the Universe could have expanded between horizon exit of the largest observable scales today and the end of inflation. We discuss the implications on inflationary models and show how the new constraints affect model selection. We also discuss the sensitivities of the current and planned GW observatories such as LIGO and LISA, and show that the constraints they could impose are always less stringent than the BBN bound.

    ↳ astro-ph.COgr-qchep-phJCAP(2021)·22 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.