Tue·Apr 16, 2024Tuesday·April 16, 2024

1. 01*

   Correlations of event activity with hard and soft processes in $p$ + Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV at STAR

   STAR Collaboration: M. I. Abdulhamid🇪🇬 · B. E. Aboona🇺🇸 · J. Adam🇨🇿 · L. Adamczyk🇵🇱 · J. R. Adams🇺🇸 · I. Aggarwal🇮🇳 · M. M. Aggarwal🇮🇳 · Z. Ahammed🇮🇳 · E. C. Aschenauer🇺🇸 · S. Aslam🇮🇳 · J. Atchison🇺🇸 · V. Bairathi🇨🇱 and 350 other authors

   With the STAR experiment at the BNL Relativisic Heavy Ion Collider, we characterize $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV p+Au collisions by event activity (EA) measured within the pseudorapidity range $eta$ $in$ [-5, -3.4] in the Au-going direction and report correlations between this EA and hard- and soft- scale particle production at midrapidity ($\eta$ $\in$ [-1, 1]). At the soft scale, charged particle production in low-EA p+Au collisions is comparable to that in p+p collisions and increases monotonically with increasing EA. At the hard scale, we report measurements of high transverse momentum (pT) jets in events of different EAs. In contrast with the soft particle production, high-pT particle production and EA are found to be inversely related. To investigate whether this is a signal of jet quenching in high-EA events, we also report ratios of pT imbalance and azimuthal separation of dijets in high- and low-EA events. Within our measurement precision, no significant differences are observed, disfavoring the presence of jet quenching in the highest 30% EA p+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV.

   nucl-exPRC(2024)·16 citations
2. 02*

   Correlation between the charge radii difference in mirror partner nuclei and the symmetry energy slope

   Xiao-Rong Ma · Shuai Sun🇨🇳 · Rong An🇨🇳 · Li-Gang Cao

   A correlation between the charge radii difference of mirror partner nuclei $\Delta R_{\mathrm{ch}}$ and the slope parameter $L$ of symmetry energy has been built to ascertain the equation of state of isospin asymmetric nuclear matter. In this work, the influences of pairing correlations and isoscalar compression modulus on the $\Delta R_{\mathrm{ch}}$ are systematically investigated based on the Skyrme energy density functional theory. The calculated results suggest that the linear correlation between $\Delta R_{\mathrm{ch}}$ and $L$ is decreased by the surface pairing correlations. The slope parameter deduced from the difference of charge radii of mirror-pair nuclei ${}^{32}$Ar-${}^{32}$Si, ${}^{36}$Ca-${}^{36}$S, ${}^{38}$Ca-${}^{38}$Ar, and ${}^{54}$Ni-${}^{54}$Fe falls into the range of $L$=42.57-50.64 MeV, that is, the rather soft equation of state of asymmetric nuclear matter. Besides, the range of the slope parameter can also be influenced by the effective forces classified by various isoscalar incompressibility coefficients.

   ↳ nucl-thnucl-exCPC(2024)·6 citations
3. 03*

   Spin entanglement of multinucleons: experimental prospects

   Dong Bai🇨🇳 · Zhongzhou Ren🇨🇳

   Multiprotons and multineutrons are among the most exotic and mysterious things ever produced on earth. They provide an exceptional opportunity to understand nuclear forces and nuclear dynamics at extreme conditions, as well as neutron stars in the heaven. Quantum entanglement, referred to as ``spooky action at a distance'' by Einstein, is a ubiquitous yet deep property of quantum systems. It not only occupies a central position in quantum information science but also is investigated intensively in high energy physics, condensed matter physics, and quantum gravity. In comparison, the study of nuclear entanglement is still in infancy, and the entanglement properties of multiprotons and multineutrons in free space are generally unknown. Here, we study the crucial problem of how to measure spin entanglement of these multinucleons in nuclear experiments, with special emphases on two- and three-nucleon states. These findings open a freshly new direction for the multinucleon research. They are also useful for understanding entanglement properties of other exotic nuclear objects.

   ↳ nucl-thnucl-ex8 citations
4. 04*

   Bayesian inference of neutron-skin thickness and neutron-star observables based on effective nuclear interactions

   Jia Zhou🇨🇳 · Jun Xu🇨🇳

   We have obtained the constraints on the density dependence of the symmetry energy from neutron-skin thickness data by parity-violating electron scatterings and neutron-star observables using a Bayesian approach, based on the standard Skyrme-Hartree-Fock (SHF) model and its extension as well as the relativistic mean-field (RMF) model. While the neutron-skin thickness data (neutron-star observables) mostly constrain the symmetry energy at subsaturation (suprasaturation) densities, they may more or less constrain the behavior of the symmetry energy at suprasaturation (subsaturation) densities, depending on the energy-density functional form. Besides showing the final posterior density dependence of the symmetry energy, we also compare the slope parameters of the symmetry energy at 0.10 fm${}^{-3}$ as well as the values of the symmetry energy at twice saturation density from three effective nuclear interactions. The present work serves as a comparison study based on relativistic and non-relativistic energy-density functionals, for constraining the nuclear symmetry energy from low to high densities using a Bayesian approach.

   ↳ nucl-thastro-ph.HEastro-ph.SRnucl-exSCPMA(2024)·12 citations
5. 05*

   A machine learning-based study of open-charm hadrons in proton-proton collisions at the Large Hadron Collider

   Kangkan Goswami🇮🇳 · Suraj Prasad🇮🇳 · Neelkamal Mallick🇮🇳 · Raghunath Sahoo🇮🇳 · Gagan B. Mohanty🇮🇳

   n proton-proton and heavy-ion collisions, the study of charm hadrons plays a pivotal role in understanding the QCD medium and provides an undisputed testing ground for the theory of strong interaction, as they are mostly produced in the early stages of collisions via hard partonic interactions. The lightest open-charm, $D^0$ meson ($c\text{Bar}u$), can originate from two separate sources. The prompt $D^0$ originates from either direct charm production or the decay of excited open charm states, while the nonprompt stems from the decay of beauty hadrons. In this paper, using different machine learning (ML) algorithms such as XGBoost, CatBoost, and Random Forest, an attempt has been made to segregate the prompt and nonprompt production modes of $D^0$ meson signal from its background. The ML models are trained using the invariant mass through its hadronic decay channel, i.e., $D^0\to {\pi }^{+}{K}^{-}$, pseudoproper time, pseudoproper decay length, and distance of closest approach of $D^0$ meson, using PYTHIA8 simulated $pp$ collisions at $\sqrt{s}=13\mathrm{TeV}$. The ML models used in this analysis are found to retain the pseudorapidity, transverse momentum, and collision energy dependence. In addition, we report the ratio of nonprompt to prompt $D^0$ yield, the self-normalized yield of prompt and nonprompt $D^0$ and explore the charmonium, $J/\psi$ to open-charm, $D^0$ yield ratio as a function of transverse momenta and normalized multiplicity. The observables studied in this manuscript are well predicted by all the ML models compared to the simulation.

   ↳ hep-phhep-exhep-thnucl-ex+1PRD(2024)·18 citations
6. 06*

   Charmonium Transport in Ultra-Relativistic Heavy-Ion Collisions at the LHC

   Biaogang Wu🇺🇸 · Ralf Rapp🇺🇸

   We provide an update on our semi-classical transport approach for quarkonium production in high-energy heavy-ion collisions, focusing on $J/\psi$ and $\psi (2S)$ mesons in 5.02 TeV Pb-Pb collisions at the Large Hadron Collider (LHC) at both forward and mid-rapidity. In particular, we employ the most recent charm-production cross sections reported in pp collisions, which are pivotal for the magnitude of the regeneration contribution, and their modifications due to cold-nuclear-matter (CNM) effects. Multi-differential observables are calculated in terms of nuclear modification factors as a function of centrality, transverse momentum, and rapidity, including the contributions from bottom-decay feeddown. For our predictions for $\psi (2S)$ production, the mechanism of sequential regeneration relative to the more strongly bound $J/\psi$ meson plays an important role in interpreting recent ALICE data.

   ↳ nucl-thnucl-exUniverse(2024)·24 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.