Tue·Jun 19, 2018Tuesday·June 19, 2018

1. 01*

   Dark Matter, Sparticle Spectroscopy and Muon $(g-2)$ in $SU(4{)}_c\times SU(2{)}_L\times SU(2{)}_R$

   M.E. Gomez🇪🇸 · S. Lola🇬🇷 · R. Ruiz de Austri🇪🇸 · Q. Shafi🇺🇸

   We explore the sparticle mass spectra including LSP dark matter within the framework of supersymmetric $SU(4{)}_c\times SU(2{)}_L\times SU(2{)}_R$ (422) models, taking into account the constraints from extensive LHC and cold dark matter searches. The soft supersymmetry-breaking parameters at $M_{GUT}$ can be non-universal, but consistent with the 422 symmetry. We identify a variety of coannihilation scenarios compatible with LSP dark matter, and study the implications for future supersymmetry searches and the ongoing muon g-2 experiment.

   hep-phJHEP(2018)·8 citations
2. 02*

   Neutrino mass observables and non-Hermitian version of Type-I seesaw model

   Sasmita Mishra🇮🇳

   We study the non-Hermitian extension of the Lagrangian of the Standard Model extended by singlet right-handed heavy neutrinos. The Yukawa coupling matrices comprise of hermitian and non-hermitian components and the neutrino mass eigenvalues are calculated for three generation case. The increased number of unknown parameters in the theory due to non-hermitian nature of coupling matrices impose problem for its productiveness. Hence we apply four zero texture for the Yukawa matrices. We consider the normal hierarchy of neutrino mass ordering and find the mixing angles and Dirac CP violating phase by diagonalizing the lepton mass matrices. The parameters of the mixing matrix are obtained in terms of the parameters of the non-hermitian Yukawa coupling matrix. The values of the angles and phase are compatible with experimental data available for neutrino mass observables and using this the non-hermitian parameters are constrained. Also, we study the constraints imposed by $CP$ violation in the lepton sector and leptogenesis on the model parameters.

   hep-phJCAP(2021)·4 citations
3. 03*

   Inclusive dijet hadroproduction with a rapidity veto constraint

   F. Caporale🇪🇸 · F. G. Celiberto🇪🇸 · G. Chachamis🇪🇸 · D. Gordo Gómez🇪🇸 · A. Sabio Vera🇪🇸

   We study ratios of azimuthal-angle distributions in Mueller-Navelet jets after imposing a rapidity veto constraint: the minijet radiation activity is restricted to only allow final-state partons separated at least a distance in rapidity $b$. It is well-known that the asymptotic growth with the rapidity separation of the two tagged jets of the NLLA BFKL Green's function requires a value of $b\simeq \mathcal{O}(2)$ in order to avoid unphysical cross sections. We further investigate this point from a phenomenological point of view and work out those values of $b$ which best fit angular distributions measured at the LHC in a realistic set-up where impact factors and parton distribution effects are also taken into account.

   hep-phNPB(2018)·65 citations
4. 04*

   Some diagrams and basic formalism to the low energy kaon-hyperon interaction

   Marcelo G. L. Nogueira Santos🇧🇷 · Celso C. Barros Jr🇧🇷

   In this work the low energy kaon-hyperon interaction is studied with nonlinear chiral invariant Lagragians considering kaons, hyperons, and the corresponding resonances in the intermediate states. We show the basic formalism to calculate the total cross sections, angular distributions, and some diagrams of interest.

   hep-ph0 citations
5. 05*

   Equations of Motion for the Standard Model Effective Field Theory: Theory and Applications

   Abdurrahman Barzinji🇩🇰 · Michael Trott🇩🇰 · Anagha Vasudevan🇩🇰

   The equations of motion for the Standard Model Effective Field Theory (SMEFT) differ from those in the Standard Model. Corrections due to local contact operators modify the equations of motion and impact matching results at sub-leading order in the operator expansion. As a consequence, a matching coefficient in ${\mathcal{L}}^{(n)}$ (for operators of dimension $n$) can be dependent on the basis choice for ${\mathcal{L}}^{(m<n)}$. We report the SMEFT equations of motion with corrections due to ${\mathcal{L}}^{(5,6)}$. We demonstrate the effect of these corrections when matching to sub-leading order by considering the interpretation of recently reported $B\to K^{(\ast )}{\ell }^{+}{\ell }^{-}$ lepton universality anomalies in the SMEFT.

   hep-phPRD(2018)·22 citations
6. 06*

   Weak decays of $B_c$ into two hadrons under flavor SU(3) symmetry

   Ruilin Zhu🇨🇳 · Xin-Ling Han🇨🇳 · Yan Ma🇨🇳 · Zhen-Jun Xiao🇨🇳

   A large number of $B_c$ meson events have been recorded at the LHCb detector, especially some two-body hadronic decay modes. We analyzed the weak decays of the $B_c$ meson into two hadron states under the flavor SU(3) symmetry. The relations among amplitudes of $B_c$ into $D+P(V)$, $B+P(V)$, $P(V)+P(V)$, $T_8+{\bar{T}}_8$ and $T_{10}+{\bar{T}}_{10}$ were investigated systematically, where $P$ ( $V$) denotes a light pseudoscalar (vector) meson and $T_{8,10}$ denotes a light baryon. The $\eta -{\eta }^{\prime }$ mixing and $\omega -\varphi$ mixing effects are also considered for the phenomenological discussions. We obtained the relations among decay widths of different $B_c$ decay channels. These results are helpful to study the two-body decay properties of the $B_c$ meson and test the flavor SU(3) symmetry.

   hep-phhep-exEPJC(2018)·12 citations
7. 07*

   Conformal field theory analysis for QCD Kondo effect

   Taro Kimura🇯🇵 · Sho Ozaki🇯🇵

   We study non-perturbative aspects of QCD Kondo effect, which has been recently proposed for the finite density and strong magnetic field systems, using conformal field theory describing the low energy physics near the IR fixed point. We clarify the symmetry class of QCD Kondo effect both for the finite density and magnetic field systems, and show how the IR fixed point is non-perturbatively characterized by the boundary condition, which incorporates the impurity effect in Kondo problem. We also obtain the low temperature behavior of several quantities of QCD Kondo effect in the vicinity of the IR fixed point based on the conformal field theory analysis.

   hep-phcond-mat.str-elhep-thPRD(2019)·21 citations
8. 08*

   Residues of ${\Lambda }_Q$-type and ${\Sigma }_Q$-type Baryons in the Bethe-Salpeter Equation Approach

   Qi-Xin Yu🇨🇳 · Zhen-Yang Wang🇨🇳 · Jing-Juan Qi🇨🇳 · Xin-Heng Guo🇨🇳

   We study the residues of ${\Lambda }_Q$-type baryons (${\Lambda }_Q$ and ${\Xi }_Q^A$) $(Q=b,c)$ and ${\Sigma }_Q$-type baryons (${\Sigma }_Q^{(\ast )}$, ${\Xi }_Q^{S(\ast )}$ and ${\Omega }_Q^{(\ast )}$) in the quark-diquark model within the Bethe-Salpeter (BS) formalism. These residues can be used, for example, in the calculations of the amplitudes in the scattering processes. After constructing the baryonic currents in the BS formalism, we derive the relations between the BS wave functions and the residues for these baryons. The BS equations are solved numerically with the kernel including the scalar confinement and the one gluon exchange terms and with the covariant instantaneous approximation being employed in the calculations. Finally, we obtain the numerical values of the residues $0.103\mathrm{GeV}\sim 0.224\mathrm{GeV}$ for ${\Lambda }_Q$, $0.143\mathrm{GeV}\sim 0.215\mathrm{GeV}$ for ${\Xi }_Q^A$, $0.262\mathrm{GeV}\sim 0.361\mathrm{GeV}$ for ${\Sigma }_Q^{(\ast )}$, $0.313\mathrm{GeV}\sim 0.460\mathrm{GeV}$ for ${\Xi }_Q^{S(\ast )}$ and $0.473\mathrm{GeV}\sim 0.571\mathrm{GeV}$ for ${\Omega }_Q^{(\ast )}$ in the ranges of the parameters in our model.

   hep-phPRD(2018)·0 citations
9. 09*

   Theoretical interpretations of DAMPE first results: a critical review

   Yoann Genolini🇧🇪

   The DAMPE experiment recently published its first results on the lepton ($e^{+}+e^{-}$) cosmic-ray (CRs) flux. These results are of importance since they account for the first direct detection of the lepton break around the energy of 1 TeV and confirm the discoveries of ground-based Cherenkov detectors. Meanwhile they reveal a new high-energy feature in the spectrum which triggered a lot of excitement on the theory side, when interpreted as the typical signature of leptophilic dark-matter annihilation. In this proceeding I mainly focus on the theoretical understanding of the lepton break. Then I quickly review the status of the more speculative line-like DAMPE excess, whose astrophysical (pulsar) or exotic (dark matter) explanation is strongly constrained by multi-messenger astronomy.

   hep-phastro-ph.HE3 citations
10. 10*

    Correlation of normal neutrino mass ordering with upper octant of ${\theta }_{23}^{}$ and third quadrant of $\delta$ via RGE-induced $\mu$-$\tau$ symmetry breaking

    Guo-yuan Huang🇨🇳 · Zhi-zhong Xing🇨🇳 · Jing-yu Zhu🇨🇳

    The recent global analysis of three-flavor neutrino oscillation data indicates that the {\it normal} neutrino mass ordering is favored over the inverted one at the $3\sigma$ level, and the best-fit values of the largest neutrino mixing angle ${\theta }_{23}^{}$ and the Dirac CP-violating phase $\delta$ are located in the higher octant and the third quadrant, respectively. We show that all these important issues can be naturally explained by the $\mu$-$\tau$ reflection symmetry breaking of massive neutrinos from a superhigh energy scale down to the electroweak scale due to the one-loop renormalization-group equations (RGEs) in the minimal supersymmetric standard model (MSSM). The complete parameter space is explored {\it for the first time} in both Majorana and Dirac cases, by allowing the smallest neutrino mass $m_1^{}$ and the MSSM parameter $\tan \beta$ to vary in their reasonable regions.

    hep-phhep-exCPC(2018)·23 citations
11. 11*

    Employing RHIC and LHC data to determine TMD gluon density in a proton

    N.A. Abdulov🇷🇺 · H. Jung🇩🇪 · A.V. Lipatov🇷🇺 · G.I. Lykasov🇷🇺 · M.A. Malyshev🇷🇺

    Transverse momentum dependent (TMD) parton distributions in a proton are important in high energy physics from both theoretical and phenomenological points of view. Using the latest RHIC and LHC data on the inclusive soft hadron production in $pp$ and $AA$ collisions at small transverse momenta, we determine the parameters of the initial TMD gluon density, derived in the framework of quark-gluon string model at the low scale ${\mu }_0\sim 1-2$ GeV and refine its large-$x$ behaviour using the LHC data on the $t\bar{t}$ production at $\sqrt{s}=13$ TeV. Then, we apply the Catani-Ciafaloni-Fiorani-Marchesini (CCFM) evolution equation to extend the obtained TMD gluon density to the whole kinematical region. In addition, the complementary TMD valence and sea quark distributions are generated. The latter are evaluated in the approximation where the gluon-to-quark splitting occurs at the last evolution step using the TMD gluon-to-quark splitting function. Several phenomenological applications of the proposed TMD quark and gluon densities to the LHC processes are discussed.

    hep-phPRD(2018)·14 citations
12. 12*

    $R_{K^{(\ast )}}$ and the origin of Yukawa couplings

    Stephen F. King🇬🇧

    We explore the possibility that the semi-leptonic $B$ decay ratios $R_{K^{(\ast )}}$ which violate $\mu -e$ universality are related to the origin of the fermion Yukawa couplings in the Standard Model. Some time ago, a vector-like fourth family (without a $Z^{\prime }$) was used to generate fermion mass hierarchies and mixing patterns without introducing any family symmetry. Recently the idea of inducing flavourful $Z^{\prime }$ couplings via mixing with a vector-like fourth family which carries gauged $U(1{)}^{\prime }$ charges has been proposed as a simple way of producing controlled flavour universality violation while elegantly cancelling anomalies. We show that the fusion of these two ideas provides a nice connection between $R_{K^{(\ast )}}$ and the origin of Yukawa couplings in the quark sector. However the lepton sector requires some tuning of Yukawa couplings to obtain the desired coupling of $Z^{\prime }$ to muons.

    hep-phJHEP(2018)·60 citations
13. 13*

    Confronting impact parameter dependent JIMWLK evolution with HERA data

    Heikki Mäntysaari🇫🇮 · Björn Schenke🇺🇸

    The small-$x$ evolution of protons is determined from numerical solutions of the JIMWLK equations, starting from an initial condition at moderate $x$ for a finite size proton. The resulting dipole amplitude is used to calculate the total reduced cross section ${\sigma }_r$ and charm reduced cross section ${\sigma }_{rc}$, as well as diffractive vector meson production. We compare results to experimental data from HERA and discuss fundamental problems arising from the regime sensitive to non-perturbative physics. We emphasize that information on the gluonic content of the proton, gluon spatial distributions and correlations over wide ranges in $x$, which can in principle be constrained by our study, are essential ingredients for describing the initial state in proton-proton and proton-ion collisions. Future electron nucleus collisions at an electron-ion collider will provide important additional insight for heavier nuclei. We further demonstrate that it is not possible to probe gluon saturation in electron-proton collision at HERA energies and that electron-heavy ion collisions will be essential to access the saturation regime.

    hep-phPRD(2018)·99 citations
14. 14*

    Fitting flavour symmetries: the case of two-zero neutrino mass textures

    Julien Alcaide🇪🇸 · Jordi Salvado🇪🇸 · Arcadi Santamaria🇪🇸

    We present a numeric method for the analysis of the fermion mass matrices predicted in flavour models. The method does not require any previous algebraic work, it offers a ${\chi }^2$ comparison test and an easy estimate of confidence intervals. It can also be used to study the stability of the results when the predictions are disturbed by small perturbations. We have applied the method to the case of two-zero neutrino mass textures using the latest available fits on neutrino oscillations, derived the available parameter space for each texture and compared them. Textures $A_1$ and $A_2$ seem favoured because they give a small ${\chi }^2$, allow for large regions in parameter space and give neutrino masses compatible with Cosmology limits. The other "allowed" textures remain allowed although with a very constrained parameter space, which, in some cases, could be in conflict with Cosmology. We have also revisited the "forbidden" textures and studied the stability of the results when the texture zeroes are not exact. Most of the forbidden textures remain forbidden, but textures $F_1$ and $F_3$ are particularly sensitive to small perturbations and could become allowed.

    hep-phJHEP(2018)·44 citations
15. 15*

    Dipole Polarizabilities of ${\pi }^{\pm }$-Mesons

    L.V. Fil'kov🇷🇺 · V.L. Kashevarov🇷🇺

    The main experimental works, where dipole polarizabilities of charged pions have been determined, are considered. Possible reasons for the differences between the experimental data are discussed. In particular, it is shown that the account of the $\sigma$-meson gives a significant correction to the value of the polarizability obtained in the latest experiment of the COMPASS collaboration. We present also new fit results for the $(\gamma \gamma \to \pi \pi )$ reaction.

    hep-phhep-exnucl-thInt.J.Mod.Phys.Conf.Ser.(2018)·4 citations
16. 16*

    Calorimetric Dark Matter Detection With Galactic Center Gas Clouds

    Amit Bhoonah🇨🇦 · Joseph Bramante🇨🇦 · Fatemeh Elahi🇮🇷 · Sarah Schon🇨🇦

    We demonstrate that dark matter heating of gas clouds hundreds of parsecs from the Milky Way Galactic center provides a powerful new test of dark matter interactions. To illustrate, we set a leading bound on nucleon scattering for 10-100 MeV mass dark matter. We also constrain millicharged dark matter models, including those proposed to match the recent EDGES 21 cm absorption anomaly. For Galactic center gas clouds, galactic fields' magnetic deflection of electromagnetically charged dark matter is mitigated, because the magnetic fields around the Galactic center are poloidal, as opposed to being aligned parallel to the Milky Way disk. We discuss prospects for detecting dark matter using a population of Galactic center gas clouds warmed by dark matter.

    hep-phastro-ph.GAPRL(2018)·78 citations
17. 17*

    The New $\nu$MSM : Radiative Neutrino Masses, keV-Scale Dark Matter and Viable Leptogenesis with sub-TeV New Physics

    Sven Baumholzer🇩🇪 · Vedran Brdar🇩🇪 · Pedro Schwaller🇩🇪

    We study the scenario in which the Standard model is augmented by three generations of right-handed neutrinos and a scalar doublet. The newly introduced fields share an odd charge under a ${\mathbb{Z}}_2$ parity symmetry. This model, commonly known as "Scotogenic", was designed to provide a mechanism for active neutrino mass generation as well as a viable dark matter candidate. In this paper we consider a scenario in which the dark matter particle is at the keV-scale. Such particle is free from X-ray limits due to the unbroken parity symmetry that forbids the mixing between active and right-handed neutrinos. The active neutrino masses are radiatively generated from the new scalars and the two heavier right-handed states with $\sim \mathcal{O}(100)$ GeV masses. These heavy fermions can produce the observed baryon asymmetry of the Universe through the combination of Akhmedov-Rubakov-Smirnov mechanism and recently proposed scalar decays. To the best of our knowledge, this is the first time that these two mechanisms are shown to be successful in any radiative model. We identify the parameter space where the successful leptogenesis is compatible with the observed abundance of dark matter as well as the measurements from the neutrino oscillation experiments. Interestingly, combining dark matter production and successful leptogenesis gives rise to strict limits from big bang nucleosynthesis which do not allow the mass of dark matter to lie above $\sim 10$ keV, providing a phenomenological hint for considered low-scale dark matter. By featuring the keV-scale dark matter free from stringent X-ray limits, successful baryon asymmetry generation and non-zero active neutrino masses, the model is a direct analogue to the $\nu$MSM model proposed by Asaka, Blanchet and Shaposhnikov. Therefore we dub the presented framework as "The new $\nu$MSM" abbreviated as $\nu \nu$MSM.

    hep-phastro-ph.HEJHEP(2018)·53 citations
18. 18*

    ${\alpha }_s$ status and perspectives (2018)

    David d'Enterria🇨🇭

    The latest experimental and theoretical developments in the high-precision determination of the strong coupling ${\alpha }_s$ are briefly reviewed. Six groups of observables: (i) lattice QCD data, (ii) hadronic $\tau$ decays, (iii) deep-inelastic $e^{\pm }p$ data and parton distribution functions (PDF) fits, (iv) event shapes and jet rates in $e^{+}{e}^{-}$ collisions, (v) Z boson hadronic decays, and (vi) top-quark cross sections in pp collisions, are used to extract the current world-average at the Z pole mass, ${\alpha }_s(m_Z^2)=0.1181\pm 0.0011$ at next-to-next-to-leading-order (NNLO), or beyond, accuracy. Additional NNLO extractions have recently appeared based on new lattice studies, the $R(s)$ ratio in $e^{+}{e}^{-}\to \text{mbox}hadrons$, updated PDF fits, energy-energy correlations in $e^{+}{e}^{-}$ collisions, jet cross sections in $e^{\pm }p$ collisions, and the full set of $pp\to t\bar{t}$ cross sections at the LHC. Inclusion of these new data into the world-average would slightly increase its value and reduce its uncertainty to ${\alpha }_s(m_Z^2)=0.1183\pm 0.0008$. Future ${\alpha }_s$ extraction perspectives with permille uncertainties at future high-luminosity $e^{+}{e}^{-}$ machines -- via W and Z hadronic decays, parton fragmentation functions, and photon $F_2(x,Q^2)$ structure function in $\gamma \gamma$ collisions -- are also discussed.

    ↳ hep-exhep-phPoS(2018)·18 citations
19. 19*

    Fitting rotation curve of galaxies by de Rham-Gabadadze-Tolley massive gravity

    Sirachak Panpanich🇹🇭 · Piyabut Burikham🇹🇭

    We investigate effects of massive graviton on the rotation curves of the Milky Way, spiral galaxies and Low Surface Brightness~(LSB) galaxies. Using a simple de Rham, Gabadadze, and Tolley (dRGT) massive gravity model, we find static spherically symmetric metric and a modified Tolman-Oppenheimer-Volkoff (TOV) equation. The dRGT nonlinear graviton interactions generate density and pressures which behave like a dark energy that can mimic the gravitational effects of a dark matter halo. We found that rotation curves of most galaxies can be fitted well by a single constant-gravity parameter $\gamma \sim m_g^{2}C\sim 10^{-28}{\mathrm{m}}^{-1}$ corresponding to the graviton mass in the range $m_g\sim 10^{-21}-10^{-30}\mathrm{eV}$ depending on the choice of the fiducial metric parameter $C\sim 1-10^{18}\text{m}$. Fitting rotation curve of the Milky Way puts strong constraint on the Yukawa-type coupling of the massive graviton exchange as a result of the shell effects.

    ↳ gr-qcastro-ph.GAhep-phPRD(2018)·51 citations
20. 20*

    Transverse Momentum Balance and Angular Distribution of $b\bar{b}$ Dijets in Pb+Pb collisions

    Wei Dai🇨🇳 · Sa Wang🇨🇳 · Shan-Liang Zhang🇨🇳 · Ben-Wei Zhang🇨🇳 · Enke Wang🇨🇳

    The productions of inclusive b-jet and $b\bar{b}$ dijets in Pb+Pb collisions have been investigated by considering the heavy quark and the light quark in-medium evolution simultaneously. The initial hard processes of inclusive b-jet and $b\bar{b}$ dijets productions are described by a next-to-leading order (NLO) plus parton shower Monte Carlo (MC) event generator SHERPA which can be well-matched with the experimental data in p+p collisions. The framework combines the Langevin transport model to describe the evolution of the bottom quark also its collisional energy loss and the higher-twist description to consider the radiative energy loss of both the bottom and light quarks. We compare the theoretical simulation of inclusive jet and inclusive b-jet $R_{\mathrm{AA}}$ in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV with the experimental data, and then present the theoretical simulation of the momentum balance of the $b\bar{b}$ dijet in Pb+Pb collisions at $5.02$ TeV with the recent CMS data for the first time. A similar trend as that in inclusive dijets has been observed in $b\bar{b}$ dijets, the production distribution is shifted to smaller $x_J$ due to the jet quenching effect. At last, the prediction of the normalized azimuthal angle distribution of the $b\bar{b}$ dijet in Pb+Pb collisions at $5.02$ TeV has been reported. The medium induced energy loss effect of the $b\bar{b}$ dijets will overall suppress its production, but the same side ($\Delta \varphi \to 0$ region) suffers more energy loss than away side ($\Delta \varphi \to \pi$ region), therefore lead to the suppression on the same side and the enhancement on the away side in the normalized azimuthal angle distribution in A+A collisions.

    ↳ nucl-thhep-phnucl-exCPC(2020)·42 citations
21. 21*

    LISA as a probe for particle physics: electroweak scale tests in synergy with ground-based experiments

    Daniel G. Figueroa🇨🇭 · Eugenio Megias🇪🇸 · Germano Nardini🇨🇭 · Mauro Pieroni🇪🇸 · Mariano Quiros🇪🇸 · Angelo Ricciardone🇳🇴 · Gianmassimo Tasinato🇬🇧

    We forecast the prospective of detection for a stochastic gravitational wave background sourced by cosmological first-order phase transitions. We focus on first-order phase transitions with negligible plasma effects, and consider the experimental infrastructures built by the end of the LISA mission. We make manifest the synergy among LISA, pulsar time array experiments, and ground-based interferometers. For phase transitions above the TeV scale or below the electroweak scale, LISA can detect the corresponding gravitational wave signal together with Einstein Telescope, SKA or even aLIGO-aVIRGO-KAGRA. For phase transitions at the electroweak scale, instead, LISA can be the only experiment observing the gravitational wave signal. In case of detection, by using a parameter reconstruction method that we anticipate in this work, we show that LISA on its own has the potential to determine when the phase transition occurs and, consequently, the energy scale above which the standard model of particle physics needs to be modified. The result may likely guide the collider community in the post-LHC era.

    ↳ astro-ph.COhep-phPoS(2018)·20 citations
22. 22*

    Modification of hyperon masses in nuclear matter

    Ki-Hoon Hong🇰🇷 · Ulugbek Yakhshiev🇰🇷 · Hyun-Chul Kim🇰🇷

    We discuss the properties of baryons within the framework of the in-medium modified SU(3) Skyrme model. The modification is performed by a minimal way, the medium functionals in the SU(2) sector being introduced. These functionals are then related to nuclear matter properties near the saturation point. The modifications in the SU(3) sector are performed with the additional changes of kaon properties in nuclear matter. The results show that the properties of baryons in the strange sector are sensitive to the in-medium modifications of the kaon properties. The consistency of the in-medium modifications of hadron properties in the present approach with other model approaches and phenomenological indications is also discussed.

    ↳ nucl-thhep-phPRC(2019)·5 citations
23. 23*

    Negative temperature for negative lapse function

    G.E. Volovik🇫🇮

    Fermion dynamics distinguishes spacetimes having the same metric $g_{\mu \nu }$, but different tetrads $e_{\mu a}$, and in particular, it distinguishes a lapse with negative sign, $N<0$.[1] Here we show that the quasiequilibrium thermodynamic state may exist, in which the region with $N<0$ has negative local temperature $T(\mathbf{r})<0$, while the global Tolman temperature $T_0$ remains positive. For bosons, only $N^2$ matters. However, if bosons are composite, they may inherit the negative $T(\mathbf{r})$ from the fermions, and thus they may distinguish the spacetimes with positive and negative lapse functions via thermodynamics.

    ↳ gr-qccond-mat.otherhep-phJETP Lett.(2019)·8 citations
24. 24*

    Rotating solutions of nonideal transverse Chern-Simons magnetohydrodynamics and the anomalous Hall current

    N. Sadooghi🇮🇷 · M. Shokri🇮🇷

    In order to gain deeper insight into the physics of the novel rotating solution of nonideal transverse magnetohydrodynamics (MHD), presented in one of our recent works, we replace the previously considered Maxwell theory with the $\mathcal{C}\mathcal{P}$ violating Maxwell-Chern-Simons (MCS) theory. In this way, dissipationless chiral magnetic (CM) and anomalous Hall (AH) currents appear in the MCS equation of motion, that, together with equations of relativistic hydrodynamics, builds the set of constitutive equations of the nonideal transverse Chern-Simons magnetohydrodynamics (CSMHD). We are, in particular, interested in the effect of these currents on the evolution of electromagnetic fields in a uniformly and longitudinally expanding quark-gluon plasma with chirality imbalance. Combining the constitutive equations of CSMHD under these assumptions, we arrive, as expected, at two distinct rotating and nonrotating solutions for electromagnetic fields. The rotation occurs with increasing rapidity and a constant angular velocity ${\omega }_0$. Remarkably, the relative angle between the electric and magnetic fields, $\delta$, turns out to be given by the coefficient of AH current ${\kappa }_E$ and the electric conductivity of the medium $\sigma$, as $\delta ={\tan }^{-1}({\kappa }_E/\sigma )$. Whereas the nonrotating solution implies the AH coefficient to be vanishing, and thus nonrotating electric and magnetic fields to be either parallel or antiparallel, the relative orientation of rotating electric and magnetic fields and the evolution of the CM conductivity ${\kappa }_B$ are strongly affected by nonvanishing ${\kappa }_E$. We explore the effect of positive and negative ${\omega }_0$ on the evolution of the CM current, and show, in particular, that a rotation of electromagnetic fields with negative ${\omega }_0$ implies a sign flip of the CM current in a chiral fluid with nonvanishing AH current.

    ↳ nucl-thcond-mat.str-elhep-phhep-thPRD(2018)·6 citations
25. 25*

    Dilepton photoproduction measures the fluctuations of initial electromagnetic fields in nuclear collisions

    Guansong Li · Kai Zhou🇩🇪 · Baoyi Chen🇨🇳

    Dilepton production from two photon interactions $\gamma \gamma \to l^{+}{l}^{-}$ are studied in semi-central and peripheral nuclear collisions. Based on Weizsäcker-Williams approach, it is shown that the dilepton photoproduction is proportional to the electromagnetic (EM) fields $\sim E^2{B}^2$ and therefore sensitive to the magnitude and lifetime of initial EM fields which last only for a short time and are hard to be measured in experiments directly. We propose dilepton photoproduction as a probe for the nuclear charge fluctuations, which are crucial for the electric/magnetic field induced chiral and charge particle evolutions. We calculate the relative standard deviation of dilepton mass spectrum with event-by-event fluctuating nuclear charge distributions (and EM fields).

    ↳ nucl-thhep-phCommun.Theor.Phys.(2020)·4 citations
26. 26*

    A new and finite family of solutions of hydrodynamics. Part I: Fits to pseudorapidity distributions

    T. Csorgo🇭🇺 · G. Kasza🇭🇺 · M. Csanad🇭🇺 · Z. F. Jiang🇨🇳

    We highlight some of the interesting properties of a new and finite, exact family of solutions of 1 + 1 dimensional perfect fluid relativistic hydrodynamics. After reviewing the main properties of this family of solutions, we present the formulas that connect it to the measured rapidity and pseudo-rapidity densities and illustrate the results with fits to p+p collisions at 8 TeV and Pb+Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV.

    ↳ nucl-thhep-exhep-phnucl-exActa Phys.Polon.B(2019)·9 citations
27. 27*

    Collapse to the Center and Ambiguity in the Asymptotic Behavior of the Off-Shell Scattering Amplitude in Singular Three-Body Problems

    Alexander E. Kudryavtsev🇷🇺 · Alexander I. Romanov🇷🇺

    We discuss some examples of equations of the three-body problem with the oscillating asymptotics at large momentum: (i) the fixed-center approximation, (ii) the unitarized equation in the fixed-center approximation, (iii) Skornyakov--Ter-Martirosyan equation, and (iv) equations with operators used in the effective field theory, i.e., which can be expanded in power-series with positive powers of momentum. We show that in the aforementioned three-body problems the situation analogous to the falling down to the center in the two-body problem takes place -- there appears an infinite number of bound states. The energy of these states is not bounded from below. In that sense the situation is close to the falling down to the center in the two-body problem.

    ↳ nucl-thhep-phPhys.Atom.Nucl.(2018)·0 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.