Nuclear Theory·nucl-th

Monday·September 22, 2025

11 papers—6 primary·5 cross-listed

01
Global Spin Alignment of (Anti-) $^{4}$ Li in Non-Central Heavy-Ion Collisions
Yun-Peng Zheng🇨🇳 · Dai-Neng Liu🇨🇳 · Lie-Wen Chen🇨🇳 · Jin-Hui Chen🇨🇳 · Che Ming Ko🇺🇸 · Yu-Gang Ma🇨🇳 · Kai-Jia Sun🇨🇳 · Jun Xu🇨🇳 · Bo Zhou🇨🇳
Non-central heavy-ion collisions produce hot and dense nuclear matter with significant fluid vorticity, which can induce global polarizations or alignments of particles with non-zero spins along the direction of the total orbital angular momentum. This phenomenon has been observed for hyperons and vector mesons in experiments. In the present study, we demonstrate that polarized nucleons lead to global spin alignment of the unstable nucleus $^{4}$ Li, which can be measured through its strong decays via $^{4} Li \to^{3} He + p$ . Assuming that $^{4}$ Li is formed through the coalescence of polarized nucleons at kinetic freeze-out, we obtain the angular distribution of the daughter particle $^{3}$ He in the rest frame of the polarized $^{4}$ Li. Taking kinetically freeze-out nucleons from an isotropic and thermalized fireball of constant vorticity and including quantum corrections up to $ℏ^{2}$ in the coalescence calculation through the Moyal star product, we find that the angular distribution of $^{3}$ He has a $cos (2 θ^{*})$ dependence with $θ^{*}$ being its angle with respect to the quantization axis of $^{4}$ Li. We also find that the $^{3}$ He angular distribution depends on both the vorticity and the polarization of kinetically freeze-out nucleons. Future measurements on the spin alignment of $^{4}$ Li in heavy-ion collisions thus offer a promising method to probe the spin dynamics, vortical structure, and spin-dependent equation-of-state of the nuclear matter produced in these collisions.
nucl-thhep-phPRC(2026)·5 citations
02
Signatures of $K^{-}$ condensation on neutron star structure and $f -$ mode frequencies
Debanjan Guha Roy🇮🇳 · Sarmistha Banik🇮🇳
Antikaon ( $K^{-}$ ) condensation within neutron star matter (NS) depends on the antikaon-nucleon interaction potential ( $U_{K}$ ). Appearance of $K^{-}$ generally softens the equation of state (EOS). The impact of this softening on the structure of the NS can be leveraged to find a telltale sign of the phase transition from nucleonic matter to $K^{-}$ condensation. To investigate the impact of $K^{-}$ condensation on NS properties using a Bayesian inference framework, we choose two sets of RMF model parameters to obtain a stiff (DD2) and relatively soft (FSU) nucleonic EOS, and explore a wide range of optical potential depths. Multimessenger observations from NICER and LIGO/Virgo constrain the optical potential values to $U_{K} = - 104.7 2_{- 12.48}^{+ 13.82}$ MeV and $U_{K} = - 66.4 6_{- 3.42}^{+ 2.47}$ MeV for the stiff and soft cases, respectively. Deeper $K^{-}$ potentials trigger condensation at a lower density, softening the EOS and lowering the corresponding maximum masses. While slopes of mass-radius and tidal deformability curves overlap between nucleonic and exotic EOSs, their curvature and $f -$ mode oscillation properties (frequency and damping time) reveal features attributable to EOS softening. However, distinguishing the specific exotic degrees of freedom responsible for the softening remains an open challenge.
nucl-thastro-ph.HEPLB(2025)·6 citations
03
Compressibility and speed of sound in magnetized nuclear matter with broken scale invariance
Pallabi Parui🇮🇳 · Nilanjan Chaudhuri🇮🇳 · Pradip Roy🇮🇳 · Sourav Sarkar🇮🇳
The thermodynamical properties of magnetized nuclear matter at finite temperature and baryon chemical potential are studied within an effective model incorporating the QCD trace anomaly effect. The presence of magnetic field induces anisotropic structure in the energy momentum tensor due to the broken rotational invariance. The study exhibits a phase transition through the sudden change of the effective nucleon mass in a certain range of baryon chemical potential and temperature. The addition of nucleonic vacuum contribution at finite magnetic field leads to the magnetic catalysis effect. The change in squared speed of sound with chemical potential at various temperatures is closely connected to the nature of phase transition in nuclear matter. The pressure anisotropy results in different values of sound speed and isothermal compressibility in the parallel and perpendicular directions with respect to the magnetic field. The smaller values of isothermal compressibility in the parallel direction compared to the perpendicular one indicate that the equation of state is stiffer along the magnetic field direction. The studies of these thermodynamic observables can have significant importance in analyzing the properties of some compact astrophysical objects as well as in the context of non-central heavy ion collision experiments.
nucl-thhep-phPRD(2025)·2 citations
04
Effects of energy levels on the double-differential cross sections of outgoing charged particles for the n+19F reaction below 20 MeV
Hanmei Cao · Fanglei Zou · Xiaojun Sun · Jingshang Zhang
The double-differential cross sections (DDCS) for $n +^{19}$ F reaction is of critical importance for elucidating the mechanisms of nuclear reaction processes, advancing applications in nuclear engineering and technology, and supporting fundamental research in nuclear astrophysics. The quantitative description of DDCS for emission products presents a persistent theoretical challenge, primarily due to the more intricate effects of energy levels than those of 1p-shell nuclei. The pick-up mechanism of complex particles, as one of the important components of statistical theory for light nuclear reactions (STLN), is improved to describe the DDCS of outgoing charged particles, considering the effect of energy levels with energy, angular momentum and parity conservations. A comprehensive analysis of all open reaction channels is performed for $n +^{19}$ F reaction below 20 MeV. After ensuring the acquisition of high-quality DDCS of the emitted neutrons, the DDCS of outgoing charged particles (including $p, d, t, α$ ) are self-consistently obtained. The results of this work are not only in good agreement with the recently measured experimental data at $E_{n}$ =14.2 MeV, but also superior to the data recommended by the current major nuclear databases. Thus, LUNF code for $n +^{19}$ F reaction is developed to obtain the ENDF-6 formatted DDCS file of the nucleon and light composite charged particles.
nucl-thEPJA(2025)·1 citation
05
Electromagnetic sum rules for 22O from coupled-cluster theory
Francesco Marino🇩🇪 · Miriam El Batchy🇩🇪 · Sonia Bacca🇩🇪
In this contribution, we discuss recent results on the determination of the electric dipole polarizability $α_{D}$ for the neutron-rich isotope $^{22}$ O within the ab initio framework. Our calculations utilize the Lorentz integral transform coupled-cluster (LIT-CC) approach with two different chiral potentials that incorporate two and three-nucleon interactions. We compare our predictions with the available experimental data and find good agreement in the low-energy region.
nucl-thEPJ Web Conf.(2025)·1 citation
06
Probing QGP using local charge fluctuations in heavy-ion collisions
Jonathan Parra🇺🇸 · Roman Poberezhniuk🇺🇸 · Volker Koch🇺🇸 · Claudia Ratti🇺🇸 · Volodymyr Vovchenko🇺🇸
We revisit the D-measure of event-by-event net-electric charge fluctuations, an idea first introduced over 20 years ago as a potential signature for the presence of quark-gluon plasma (QGP) in heavy-ion collisions. We developed a quantitative framework that incorporates resonance-decay effects, global and local charge conservation, and experimental kinematic cuts. Folding these effects into a formalism of density correlations yields an improved expression for the $D$ -measure inside acceptance. We make comparisons with ALICE data for Pb-Pb collisions at $s_{NN} = 2.76$ ~TeV. We find that a hadron-gas scenario can describe the data only for a very short charge conservation range, while a QGP scenario is in good agreement with the measurement and is relatively insensitive to the charge conservation range. A Bayesian comparison of both scenarios shows moderate evidence for freeze-out of charge fluctuations in the QGP phase.
nucl-thhep-phEPJ Web Conf.(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Global Spin Alignment of (Anti-)4Li in Non-Central Heavy-Ion Collisions

Signatures of K− condensation on neutron star structure and f−mode frequencies

Compressibility and speed of sound in magnetized nuclear matter with broken scale invariance

Effects of energy levels on the double-differential cross sections of outgoing charged particles for the n+19F reaction below 20 MeV

Electromagnetic sum rules for 22O from coupled-cluster theory

Probing QGP using local charge fluctuations in heavy-ion collisions

Affiliations

Global Spin Alignment of (Anti-) $^{4}$ Li in Non-Central Heavy-Ion Collisions

Signatures of $K^{-}$ condensation on neutron star structure and $f -$ mode frequencies