Fri·Feb 17, 2023Friday·February 17, 2023

1. 01*

   Collective Excitation in High-Energy Nuclear Collisions -- In Memory of Professor Lianshou Liu

   Huan Zhong Huang🇺🇸 · Feng Liu🇨🇳 · Xiaofeng Luo🇨🇳 · Shusu Shi🇨🇳 · Fuqiang Wang🇺🇸 · Nu Xu🇺🇸

   We celebrate the legacies of our friend and mentor Professor Lianshou Liu who was one of the pioneers for the phenomenology of multi-particle interactions and initiated the physics of relativistic heavy-ion collisions in China. In this article, we discuss some of the recent exciting experimental observations on the collective phenomena including collectivity, chirality, criticality, strangeness production, and thermal equilibrium in high-energy nuclear collisions. Future directions, especially the physics at high baryon density, will be discussed with a focus on the first-order phase boundary and hyperon-nucleon interactions.

   nucl-exnucl-thSymmetry(2023)·6 citations
2. 02*

   Cross-shell states in ${}^{15}$C: a test for p-sd interactions

   J. Lois-Fuentes🇪🇸 · B. Fernández-Domínguez🇪🇸 · X. Pereira-López🇪🇸 · F. Delaunay🇫🇷 · W. N. Catford🇬🇧 · A. Matta🇫🇷 · N. A. Orr🇫🇷 · T. Duguet🇫🇷 · T. Otsuka🇯🇵 · V. Somà🇫🇷 · O. Sorlin🇫🇷 · T. Suzuki🇯🇵 and 50 other authors

   The low-lying structure of ${}^{15}$C has been investigated via the neutron-removal ${}^{16}$C$(d,t)$ reaction. Along with bound neutron sd-shell hole states, unbound p-shell hole states have been firmly confirmed. The excitation energies and the deduced spectroscopic factors of the cross-shell states are an important measure of the $[(p{)}^{-1}(sd{)}^2]$ neutron configurations in ${}^{15}$C. Our results show a very good agreement with shell-model calculations using the SFO-tls interaction for ${}^{15}$C. However, a modification of the $p$-$sd$ and $sd$-$sd$ monopole terms was applied in order to reproduce the $N=9$ isotone ${}^{17}$O. In addition, the excitation energies and spectroscopic factors have been compared to the first calculations of ${}^{15}$C with the $abinitio$ self-consistent Green's function method employing the NNLO${}_{sat}$ interaction. The results show the sensitivity to the size of the $N=8$ shell gap and highlight the need of going beyond the current truncation scheme in the theory.

   nucl-exnucl-thPLB(2023)·3 citations
3. 03*

   Possible Existence of Extremely Neutron-Rich Superheavy Nuclei in Neutron Star Crusts Under a Superstrong Magnetic Field

   Kazuyuki Sekizawa🇯🇵 · Kentaro Kaba

   We investigate outer crust compositions for a wide range of magnetic field strengths, up to $B\simeq 4\times 10^{18}$ G, employing the latest experimental nuclear masses supplemented with various mass models. The essential effects of the magnetic field are twoholds: 1) Enhancement of electron fraction, which is connected to that of protons via the charge neutrality condition, due to the Landau-Rabi quantization of electron motion perpendicular to the field, namely, neutron-richness is suppressed for a given pressure. As a result, 2) nuclei can exist at higher pressures without dripping out neutrons. By exploring optimal outer-crust compositions from all possible nuclei predicted by theoretical models, we find that neutron-rich heavy nuclei with neutron magic numbers 50, 82, 126, as well as 184, with various proton numbers emerge for $B\gtrsim 10^{17}$ G. Moreover, we show that superheavy nuclei with proton numbers $Z\ge 104$, including unknown elements such as $Z=119,120,122$, and/or $124$, depending on mass models, may emerge as an equilibrium composition at bottom layers of the outer crust for $B\gtrsim 10^{18}$ G, which are extremely neutron-rich ($N\approx 260$-$287$, i.e., $N/Z\approx 2.2$-$2.4$). We point out that those extremely neutron-rich superheavy nuclei locate around the next neutron magic number $N=258$ after $N=184$, underlining importance of nuclear structure calculations under such really exotic, extreme conditions. We demonstrate how the superstrong magnetic field substantially alters crustal properties of neutron stars, which may have detectable consequences.

   ↳ nucl-thastro-ph.HEnucl-ex7 citations
4. 04*

   $K^{\ast 0}$ meson production using a transport and a statistical hadronization model at energies covered by the RHIC beam energy scan

   Aswini Kumar Sahoo🇮🇳 · Md. Nasim🇮🇳 · Subhash Singha🇨🇳

   In this paper, we discuss the centrality and energy dependence of $K^{\ast 0}$ resonance production using ultrarelativistic quantum molecular dynamics (UrQMD) and thermal models. The $K^{\ast 0}/K$ ratios obtained from the UrQMD and thermal models are compared with measurements done by the STAR experiment in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, and 39 GeV. The $K^{\ast 0}/K$ ratio from the thermal model is consistent with data in most-peripheral collisions, however it overpredicts the ratio in central Au+Au collisions. This could be due to the fact that the thermal model does not have a hadronic rescattering phase, which is expected to be dominant in more central collisions. Furthermore, we have studied the $K^{\ast 0}/K$ ratio from UrQMD by varying the hadron propagation time ($\tau$) within the range 5 to 50 fm/c. It was found that the $K^{\ast 0}/K$ ratio decreases with increasing $\tau$. Comparison between data and UrQMD suggest, one needs to consider a $\tau$ $\approx$ 10-50 fm/c to explain data at $\sqrt{s_{NN}}$ = 7.7-39 GeV in Au+Au collisions. We also predict the rapidity distribution of $K^{\ast 0}$ from UrQMD which could be measured in the STAR beam energy scan phase II (BES-II) program.

   ↳ nucl-thhep-phnucl-exPRC(2023)·14 citations
5. 05*

   Properties of Infinite Nuclear Medium from QCD Sum Rules and the Neutron Star-Black Hole Mass Gap

   Bijit Singha🇮🇳 · Debasish Das🇮🇳 · Leonard S. Kisslinger🇺🇸

   A non-perturbative framework is provided to connect QCD with nuclear phenomenology in the intermediate and high density regime. Using QCD Sum Rules, in-medium scalar and vector self-energies of nucleons are calculated as functions of the density of an infinite nuclear medium. The self-energies are used in the relativistic mean field theory lagrangian of a high-density nuclear medium to find the binding energy of in-medium nucleons and the value of light quark condensate, $⟨\bar{q}q{⟩}_{\mathrm{vac}}=-(0.288\mathrm{GeV}{)}^3$, in the Borel-improved resummation scheme. The critical mass of an ideal neutron star is obtained by coupling a uniform saturation energy density of cold, dense nuclear matter to Einstein equation in hydrostatic equilibrium. Since it is less likely for a neutron star core to avoid deconfinement and enter the rigid vector repulsion phase where the speed of sound can smoothly approach from conformal to causal limit, a gap should exist in the stellar mass spectrum, $[3.48M_{\odot },5.47M_{\odot }]$, where it would be rare to find any isolated, cold, non-rotating neutron star or a black hole.

   ↳ hep-phastro-ph.HEnucl-exnucl-th2 citations
6. 06*

   Effects of Coulomb and isospin symmetry breaking interactions on neutron-skin thickness

   Tomoya Naito🇯🇵 · Gianluca Colò🇮🇹 · Haozhao Liang🇯🇵 · Xavier Roca-Maza🇮🇹 · Hiroyuki Sagawa🇯🇵

   Both the Coulomb interaction and isospin symmetry breaking (ISB) parts of the nuclear interaction break the isospin symmetry in atomic nuclei. Effects of these two kinds of interaction on properties of atomic nuclei, especially, the mass difference of mirror nuclei and the neutron-skin thickness of $N=Z$ and $N\ne Z$ nuclei, are discussed. It is found that corrections to the Hartree-Fock-Slater approximation for the Coulomb interaction negligibly affect the neutron-skin thickness, while the charge-symmetry breaking term originating from the strong interaction might affect it non-negligibly. According to our calculations, the ISB terms other than the Coulomb interaction affect the estimation of the density dependence of the symmetry energy, $L$, by about $0$--$12\mathrm{MeV}$ using the correlation with the neutron-skin thickness.

   ↳ nucl-thnucl-exPRC(2023)·19 citations
7. 07*

   Neutrino Structure Functions from GeV to EeV Energies

   Alessandro Candido🇮🇹 · Alfonso Garcia🇺🇸 · Giacomo Magni🇳🇱 · Tanjona Rabemananjara🇳🇱 · Juan Rojo🇳🇱 · Roy Stegeman🇬🇧

   The interpretation of present and future neutrino experiments requires accurate theoretical predictions for neutrino-nucleus scattering rates. Neutrino structure functions can be reliably evaluated in the deep-inelastic scattering regime within the perturbative QCD (pQCD) framework. At low momentum transfers ($Q^2\le \mathrm{few}$ GeV${}^2$), inelastic structure functions are however affected by large uncertainties which distort event rate predictions for neutrino energies $E_{\nu }$ up to the TeV scale. Here we present a determination of neutrino inelastic structure functions valid for the complete range of energies relevant for phenomenology, from the GeV region entering oscillation analyses to the multi-EeV region accessible at neutrino telescopes. Our NNSF$\nu$ approach combines a machine-learning parametrisation of experimental data with pQCD calculations based on state-of-the-art analyses of proton and nuclear parton distributions (PDFs). We compare our determination to other calculations, in particular to the popular Bodek-Yang model. We provide updated predictions for inclusive cross sections for a range of energies and target nuclei, including those relevant for LHC far-forward neutrino experiments such as FASER$\nu$, SND@LHC, and the Forward Physics Facility. The NNSF$\nu$ determination is made available as fast interpolation LHAPDF grids, and can be accessed both through an independent driver code and directly interfaced to neutrino event generators such as GENIE.

   ↳ hep-phastro-ph.HEhep-exnucl-ex+1JHEP(2023)·58 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.