Fri·Jan 7, 2022Friday·January 7, 2022

1. 01*

   Hyperons and ${\Theta }_s^{+}$ in Holographic QCD

   Yizhuang Liu🇵🇱 · Maciej A. Nowak🇵🇱 · Ismail Zahed🇺🇸

   We revisit the holographic description of strange baryons in the context of the Sakai-Sugimoto construction, by considering the strange quark mass as heavy. Hyperons are described by a massive $(K,K^{\ast })$ multiplet, bound to a light-flavor instanton in bulk, much in the spirit of the Callan-Klebanov construction. The modular Hamiltonian maps onto the Landau problem, a charged particle in a 2-dimensional external magnetic field, induced by the bulk Chern-Simons interaction, plus spin-orbit coupling. The ensuing holographic hyperon spectrum compares fairly with the empirical one. The holographic strange pentaquark baryon ${\Theta }_s^{+}$ is shown to be unbound.

   ↳ hep-phnucl-exnucl-thPRD(2022)·5 citations
2. 02*

   Status of Lattice QCD Determination of Nucleon Form Factors and their Relevance for the Few-GeV Neutrino Program

   Aaron S. Meyer🇺🇸 · André Walker-Loud🇺🇸 · Callum Wilkinson🇺🇸

   Calculations of neutrino-nucleus cross sections begin with the neutrino-nucleon interaction, making the latter critically important to flagship neutrino oscillation experiments, despite limited measurements with poor statistics. Alternatively, lattice QCD (LQCD) can be used to determine these interactions from the Standard Model with quantifiable theoretical uncertainties. Recent LQCD results of $g_{\mathrm{A}}$ are in excellent agreement with data, and results for the (quasi-)elastic nucleon form factors with full uncertainty budgets are expected within a few years. We review the status of the field and LQCD results for the nucleon axial form factor, $F_{\mathrm{A}}(Q^2)$, a major source of uncertainty in modeling sub-GeV neutrino-nucleon interactions. Results from different LQCD calculations are consistent, but collectively disagree with existing models, with potential implications for current and future neutrino oscillation experiments. We describe a road map to solidify confidence in the LQCD results and discuss future calculations of more complicated processes, important to few-GeV neutrino oscillation experiments.

   ↳ hep-lathep-exhep-phnucl-ex+1Ann.Rev.Nucl.Part.Sci.(2022)·81 citations
3. 03*

   Anomalous enhancement of dilepton production as a precursor of color superconductivity

   Toru Nishimura🇯🇵 · Masakiyo Kitazawa🇯🇵 · Teiji Kunihiro🇯🇵

   We compute the modification of the photon self-energy due to dynamical diquark fluctuations developed near the critical temperature of the color superconductivity through the Aslamasov-Larkin, Maki-Thompson and density of states terms, which are responsible for the paraconductivity in metals at vanishing energy and momentum. It is shown that the rate has a significant enhancement at low invariant-mass region over a rather wide range of temperature in the normal phase. This enhancement is worth exploration in the relativistic heavy-ion collisions, which may thereby reveal the significance of the diquark fluctuations in dense quark matter.

   ↳ hep-phnucl-exnucl-thPTEP(2022)·18 citations
4. 04*

   Analyzing transverse momentum spectra by a new method in high-energy collisions

   Li-Li Li🇨🇳 · Fu-Hu Liu🇨🇳 · Muhammad Waqas🇨🇳 · Muhammad Ajaz🇵🇰

   We analyzed the transverse momentum spectra of positively and negatively charged pions (${\pi }^{+}$ and ${\pi }^{-}$), positively and negatively charged kaons ($K^{+}$ and $K^{-}$), protons and antiprotons ($p$ and $\bar{p}$), as well as $\varphi$ produced in mid-(pseudo)rapidity region in central nucleus--nucleus (AA) collisions over a center-of-mass energy range from 2.16 to 2760 GeV per nucleon pair. The transverse momentum of the considered particle is regarded as the joint contribution of two participant partons which obey the modified Tsallis-like transverse momentum distribution and have random azimuths in superposition. The calculation of transverse momentum distribution of particles is performed by the Monte Carlo method and compared with the experimental data measured by international collaborations. The excitation functions of effective temperature and other parameters are obtained in the considered energy range. With the increase of collision energy, the effective temperature parameter increases quickly and then slowly. The boundary appears at around 5 GeV, which means the change of reaction mechanism and/or generated matter.

   ↳ hep-phhep-exnucl-exnucl-thUniverse(2022)·17 citations
5. 05*

   Anatomy of octupole correlations in ${}^{96}$Zr with a symmetry-restored multidimensionally-constrained covariant density functional theory

   Yu-Ting Rong🇨🇳 · Xian-Ye Wu🇨🇳 · Bing-Nan Lu🇨🇳 · Jiang-Ming Yao🇨🇳

   A recent analysis based on the STAR measurement in relativistic heavy-ion collision experiments provides evidence of octupole correlation in the ground state of ${}^{96}$Zr, the description of which presents a challenge to nuclear structure models. In this work, we perform projection-after-variation calculations for ${}^{96}$Zr based on a multidimensionally-constrained relativistic Hartree-Bogoliubov model. Our results show that an octupole deformed shape is favored in energy after symmetry restoration, and this phenomenon cannot be reproduced in the pure mean-field calculations. These complex structures originate from the competition among various shell structures in this mass region. Our results suggest that the allowance of symmetry breaking at the mean-field level and the restoration of broken symmetries are essential elements for understanding the structure of ${}^{96}$Zr in density functional theories.

   ↳ nucl-thnucl-exPLB(2023)·32 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.