Nuclear Theory·nucl-th

Monday·October 28, 2024

12 papers—4 primary·8 cross-listed

05
[Submitted on 24 Oct 2024] (cross-list from astro-ph.HE)
Limiting Rotation Rate of Neutron Stars from Crust Breaking and Gravitational Waves
J. A. Morales · C. J. Horowitz
Neutron stars are not observed to spin faster than about half their breakup rate. This limiting rotational frequency may be related to the strength of their crusts. As a star spins up from accretion, centrifugal forces stress the crust. We perform finite-element simulations of rotating neutron stars and find that the crust fails at rotation rates about half the breakup rate. Given uncertainties in microphysics, we have not determined the crust configuration after this failure. Instead, we argue that the crust may fail in an asymmetric way and could produce a configuration with a significant ellipticity (fractional difference in moments of inertia). If the ellipticity is large, a rotating star will radiate gravitational waves that may limit further spin up. These stars may be promising sources for LIGO / VIRGO and next generation gravitational wave detectors.
Comments:
7 pages, 3 figures, 1 table. Additional discussion added including dependence on equation of state. ApJL in press
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2410.19111 [pdf]
ApJL(2025)·7 citations
06
[Submitted on 25 Oct 2024] (cross-list from nucl-ex)
Comparing effective temperatures in standard, Tsallis, and q-dual statistics from transverse momentum spectra of identified light charged hadrons produced in gold--gold collisions at RHIC energies
Ting-Ting Duan🇨🇳 · Pei-Pin Yang🇨🇳 · Peng-Cheng Zhang🇨🇳 · Hai-Ling Lao🇨🇳 · Fu-Hu Liu🇨🇳 · Khusniddin K. Olimov🇺🇿
This study investigates the transverse momentum ( $p_{T}$ ) spectra of identified light charged hadrons produced in gold--gold (Au+Au) collisions across various centrality classes at center-of-mass energies per nucleon pair, $s_{N N}$ , ranging from 7.7 to 200 GeV, as measured by the STAR Collaboration at the Relativistic Heavy Ion Collider (RHIC). The analysis employs standard (Bose-Einstein/Fermi-Dirac), Tsallis, and q-dual statistics to fit the same $p_{T}$ spectra and derive distinct effective temperatures: $T_{Standard}$ , $T_{Tsallis}$ , and $T_{q-dual}$ . In most instances, there exists an approximately linear relationship or positive correlation between $T_{Tsallis}$ and $T_{Standard}$ , as well as between $T_{q-dual}$ and $T_{Standard}$ , when considering $T_{Standard}$ as a baseline. However, while both $T_{Tsallis}$ and $T_{q-dual}$ increase from semi-central to central Au+Au collisions at 62.4 GeV and 200 GeV, where QGP is expected, changes in $T_{Standard}$ occur more gradually. This work suggests that $T_{Standard}$ is better suited for characterizing phase transitions between hadronic matter and QGP compared to $T_{Tsallis}$ or $T_{q-dual}$ , primarily due to the considerations related to entropy index in the Tsallis and q-dual statistics.
Comments:
19 pages, 9 figures. The European Physical Journal Plus, accepted
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2410.19266 [pdf]
Eur.Phys.J.Plus(2024)·5 citations
07
[Submitted on 25 Oct 2024] (cross-list from hep-lat)
Locating Critical Points Using Ratios of Lee-Yang Zeros
Tatsuya Wada🇯🇵 · Masakiyo Kitazawa🇯🇵 · Kazuyuki Kanaya🇯🇵
We propose a method to numerically determine the location of a critical point in general systems using the finite-size scaling of Lee-Yang zeros. This method makes use of the fact that the ratios of Lee-Yang zeros on various spatial volumes intersect at the critical point. While the method is similar to the Binder-cumulant analysis, it is advantageous in suppressing the finite-volume effects arising from the mixing of variables in general systems. We show that the method works successfully for numerically locating the CP in the three-dimensional three-state Potts model with a nonzero external field.
Comments:
6 pages, 3 figures, Minor changes
Subjects:
High Energy Physics — Lattice (hep-lat); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2410.19345 [pdf]
PRL(2025)·10 citations
08
[Submitted on 25 Oct 2024] (cross-list from nucl-ex)
First Experimental Test of the Ratio Method
S. Ota · P. Capel · G. Christian · V. Durant · K. Hagel · E. Harris · R.C. Johnson · Z. Luo · F.M. Nunes · M. Roosa · A. Saastamoinen · D.P. Scriven
The ratio is a new reaction observable suggested to extract accurately structure information on halo nuclei. It corresponds to the ratio of differential cross sections for scattering and breakup, which is predicted to remove the uncertainty related to the reaction dynamics. We present here the first experimental test of the method for the 11Be + 12C collision at ELab = 20A MeV performed at Texas A&M University. Differential cross sections for scattering and inclusive one-neutron breakup have been measured with the new detector array BlueSTEAl. The ratio of cross sections is very smooth and independent of the projectile-target interaction, which demonstrates the validity of the ratio method. We extend our analysis to existing 11Be + 208Pb data, confirming that the method works well on any target.
Comments:
Contribution to the proceedings of the 14th International Conference on Nucleus-Nucleus Collisions (NN2024) (4 pages, 2 figures)
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2410.19377 [pdf]
NPA(2025)·0 citations
09
[Submitted on 25 Oct 2024] (cross-list from hep-ph)
Deciphering the mechanism of $J / ψ$ -nucleon scattering
Bing Wu🇨🇳 · Xiang-Kun Dong🇩🇪 · Meng-Lin Du🇨🇳 · Feng-Kun Guo🇨🇳 · Bing-Song Zou🇨🇳
The low-energy $J / ψ N$ scattering is important for various reasons: it is related to the hidden-charm $P_{c}$ pentaquark states, provides insights into the role of gluons in nucleon structures, and is relevant to the $J / ψ$ properties in nuclear medium. The scattering can happen through two distinct mechanisms: the coupled-channel mechanism via open-charm meson-baryon intermediate states, and the soft-gluon exchange mechanism. We investigate the $J / ψ N$ $S$ -wave scattering length through both mechanisms, and find that the soft-gluon exchange mechanism leads to a scattering length at least one order of magnitude larger than that from the coupled-channel mechanism and thus is the predominant one. The findings can be verified by lattice calculations and will enhance our understanding of the scattering processes breaking the Okubo-Zweig-Iizuka rule.
Comments:
9 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2410.19526 [pdf]
Fund.Res.(2025)·20 citations
10
[Submitted on 25 Oct 2024] (cross-list from hep-ph)
$P$ -wave charmonium contribution to hidden-charm states from reanalysis of lattice QCD data
Pan-Pan Shi🇪🇸 · Miguel Albaladejo🇪🇸 · Meng-Lin Du🇨🇳 · Feng-Kun Guo🇨🇳 · Juan Nieves🇪🇸
We reanalyze, considering the contribution of $P$ -wave charmonia, lattice data for the $D D ˉ$ - $D_{s} D ˉ_{s}$ coupled-channel of S. Prelovsek et al. [JHEP 06, 035 (2021)] and $D D ˉ^{*}$ systems of S. Prelovsek et al. [Phys. Rev. Lett. 111, 192001 (2013)] with $m_{π} ≃ 280$ and $266$ MeV, and $L = 24 a /32 a$ ( $a ≃ 0.09$ fm) and $L = 16 a$ ( $a ≃ 0.1239 (13)$ fm), respectively. The hidden-charm states with $J^{P C} = 0^{++}$ , $1^{++}$ , and $2^{++}$ quantum numbers are then searched for. For $0^{++}$ , the analysis reveals three poles in the $D D ˉ$ - $D_{s} D ˉ_{s}$ coupled-channel amplitude, corresponding to three states. Two of these poles, located near the $D D ˉ$ and $D_{s} D ˉ_{s}$ thresholds, can be interpreted as mostly molecular states. A third pole above the $D_{s} D ˉ_{s}$ threshold is originated from the $P$ -wave $χ_{c 0} (2 P)$ charmonium state. The number of poles found in the $D D ˉ$ - $D_{s} D ˉ_{s}$ system is the same as that found in the original lattice analysis though the position of the third pole changes sizeably. In the $1^{++}$ sector, we find two poles in the complex energy plane. The first one is related to the molecular $X (3872)$ state, with a compositeness exceeding $90%$ , while the second one, stemming from the $χ_{c 1} (2 P)$ charmonium, appears above the $D D ˉ^{*}$ threshold and it likely corresponds to the recently discovered $χ_{c 1} (4010)$ state. In the $2^{++}$ sector, we also report two poles and find that the dressed $χ_{c 2} (2 P)$ is lighter than the $D^{*} D ˉ^{*}$ molecular state, with the dynamics of the latter closely related to that of the heavy-quark spin-symmetry partner of the $X (3872)$ . Our exploratory study of the $1^{++}$ and $2^{++}$ sectors offers valuable insights into their dynamics, but given that the fits that we carry out are underconstrained, more lattice data are required to draw robust conclusions.
Comments:
25 pages, 15 figures. Version to appear in Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2410.19563 [pdf]
PRD(2025)·14 citations
11
[Submitted on 25 Oct 2024] (cross-list from hep-ph)
Formation, dissociation and regeneration of charmonia within microscopic Langevin simulations
Naomi Oei🇩🇪 · Nadja Krenz🇩🇪 · Juan Torres-Rincon🇩🇪 · Hendrik van Hees🇩🇪 · Carsten Greiner🇪🇸
We present a microscopic dynamical model to study the formation, dissociation, and recombination processes of charmonium states in a heat bath at constant temperature and volume. Within this classical approach, heavy quarks are described as Brownian particles in a background medium of light constituents and can therefore be modeled by a Fokker-Planck equation with constant transport coefficients, which is then implemented through relativistic Langevin simulations. The heavy quarks interact classically via a Coulomb-like screened potential to form a bound state if the relative energy of the pair becomes negative. Dissociation of bound states is possible as a result of screening effects on the potential as well as through scatterings with plasma particles. We demonstrate the full equilibration of the system and show that the resulting equilibrium charmonium yields are in accordance with the Statistical Hadronization Model.
Comments:
11 pages, 10 figures; typos corrected, reference list updated, Fig. 4 added
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2410.19619 [pdf]
PRD(2025)·11 citations
12
[Submitted on 25 Oct 2024] (cross-list from hep-ph)
Approaching Stable Quark Matter
Yang Bai🇺🇸 · Ting-Kuo Chen🇺🇸
The determination of whether the ground state of baryon matter in Quantum Chromodynamics (QCD) is the ordinary nucleus or a quark matter state remains a long-standing question in physics. A critical parameter in this investigation is the bag parameter $B$ , which quantifies the QCD vacuum energy and can be computed using nonperturbative methods such as Lattice QCD (LQCD). By combining the equation of state derived from perturbative QCD (pQCD) with the bag parameter to fit the LQCD-simulated data for isospin-dense matter, we address the stability of quark matter within the LQCD+pQCD framework. Our findings suggest that the current data imposes an upper bound on $B^{1/4} ≲ 160$ MeV, approaching a conclusive statement on quark matter stability. Given the lower bound on $B$ from the quark condensate contribution to the vacuum energy, the stable 2-flavor quark matter remains possible, whereas the stable 2+1-flavor quark matter is excluded, assuming complete deconfinement and chiral-symmetry restoration and the reliability of pQCD at baryon chemical potentials around the proton mass. Additionally, we derive more general thermodynamic bounds on the quark matter energy-per-baryon and $B$ , which, while weaker, provide complementary insights.
Comments:
31 pages, 14 figures, matches the published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2410.19678 [pdf]
EPJC(2026)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE