Nuclear Theory·nucl-th

Tuesday·April 1, 2025

21 papers—11 primary·10 cross-listed

01
[Submitted on 29 Mar 2025]
Separating non-collective effects in d-Au collisions
Satya Ranjan Nayak🇮🇳 · Akash Das🇮🇳 · B.K. Singh🇮🇳
In this work, we present the multiplicity and yield of charged hadrons and particle ratios in d-Au collisions at $s_{N N} = 200$ GeV using the PYTHIA8/Angantyr. The model reproduces the multiplicity ( $N_{c h}$ ) and pseudo-rapidity distribution reasonably well in minimum-biased d-Au collisions without assuming the formation of a thermalized medium. The invariant yield from Angantyr underpredicts the data in central collisions. We discussed the similarity between the nuclear modification factor $R_{AA}$ and data/MC from Angantyr and the possibility of using it as a model-dependent observable to check in-medium effects. The data/MC suggests that the central d-Au collisions exhibit signals like baryon enhancement, but no high $p_{T}$ suppression was found. The d-Au collisions have a much smaller invariant yield than the thermal model calculation for similar $N_{p a r t}$ .
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2503.23019 [pdf]
EPJC(2026)·2 citations
02
[Submitted on 29 Mar 2025]
Relativistic mean-field predictions for dense matter equation of state and application to neutron stars
Luca Passarella🇮🇹 · Jerome Margueron🇺🇸 · Giuseppe Pagliara🇮🇹
Relativistic mean-field models (RMF) based on the exchange of $σ$ , $ω$ , and $ρ$ mesons including non-linear nucleon- $σ$ couplings and density-dependent $ρ$ coupling, are considered. A large set of models is generated using the Markov chain Monte Carlo approach and Bayesian statistics to reproduce nuclear physics knowledge encoded in terms of the nuclear empirical parameters and $χ$ EFT predictions for low-density neutron matter. These models are filtered, in a second step, using astrophysical constraints: the tidal deformability obtained from GW170817 parameter estimation and the observational masses deduced from radio-astronomy. We then obtain a set of selected RMF models that are compatible with present nuclear and astrophysical constraints and that can be employed to make predictions and to quantity their uncertainties. Predictions for masses and radii are compared to NICER masses-radii analyses for PSR J0030+0451 and PSR J0740+6620. We find that RMF models can be made soft enough to predict low values for neutron star radii compatible with GW170817 and, at larger densities, stiff enough to be compatible with NICER analyses for massive neutron stars. Our models can also reach large values for the maximum mass, up to 2.6 $M_{⊙}$ . In addition, for the core composition, we obtain a large distribution of the proton fraction for canonical mass neutron stars, some of them allowing the direct URCA fast cooling process. For massive neutron stars, however, most of our models suggest a large proton fraction in the core allowing direct URCA fast cooling process.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2503.23028 [pdf]
PRC(2025)·12 citations
03
[Submitted on 29 Mar 2025]
Guiding center hydrodynamics with spin
Rajeev Singh🇷🇴
We build upon the recently formulated guiding-center kinetic theory for guiding-center plasma by incorporating spin degrees of freedom in the presence of electromagnetic fields. This approach yields a streamlined set of equations for guiding-center ideal hydrodynamics with spin--fewer than those in traditional spin hydrodynamics--owing to a restriction on motion perpendicular to the magnetic field. We propose that this framework offers a promising tool to comprehending how matter behaves under the influence of intense magnetic fields, such as spin polarization effects observed in experimental measurements.
Comments:
8 pages; comments and feedbacks are welcome; revised and accepted version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2503.23061 [pdf]
J.Subatomic Part.Cosmol.(2025)·6 citations
04
[Submitted on 29 Mar 2025]
Many-channel microscopic cluster model of $^{8}$ Be. I. Formation of high-energy resonance states
V. I. Zhaba · Yu. A. Lashko · V. S. Vasilevsky
The nature and structure of high-energy resonance states in $^{8}$ Be, located just below and above the $p +^{7}$ Li threshold, are investigated in detail. A microscopic many-cluster and many-channel model is employed to study the formation of these resonances. This model includes three distinct three-cluster configurations: $^{4}$ He+ $^{3}$ H+ $p$ , $^{4}$ He+ $^{3}$ He+ $n$ , and $^{4}$ He+ $d$ + $d$ , enabling a comprehensive treatment of all major binary decay channels of $^{8}$ Be, namely $^{4}$ He+ $^{4}$ He, $p +^{7}$ Li, $n +^{7}$ Be, and $d +^{6}$ Li. The primary focus of our analysis is the structure and dominant decay channels of the twin $1^{+}$ , $2^{+}$ , $3^{+}$ , and $4^{+}$ resonance states. Additionally, we propose and implement a model to clarify how the $2^{+}$ resonance states lying below the $p +^{7}$ Li threshold are formed. We demonstrate that these resonances are Feshbach-type states arising due to coupling of the open $^{4}$ He+ $^{4}$ He channel with the closed channels $p +^{7}$ Li, $n +^{7}$ Be, and $d +^{6}$ Li at these energies. Overall, the present approach provides a realistic description of the experimentally observed resonance spectrum near the $^{7}$ Li+ $p$ decay threshold, including negative-parity states $1^{-}$ and $2^{-}$ . Our results are consistent with other microscopic calculations but offer more detailed insight into the internal structure and decay pathways of these resonances.
Comments:
37 pages, 11 figures, 10 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2503.23222 [pdf]
PRC(2025)·1 citation
05
[Submitted on 29 Mar 2025]
Quantum Simulations of Fundamental Physics
Martin J. Savage🇺🇸
Simulating the dynamics of non-equilibrium matter under extreme conditions lies beyond the capabilities of classical computation alone. Remarkable advances in quantum information science and technology are profoundly changing how we understand and explore fundamental quantum many-body systems, and have brought us to the point of simulating essential aspects of these systems using quantum computers. I discuss highlights, opportunities and the challenges that lie ahead.
Comments:
Plenary presentation at The 11th International Workshop on Chiral Dynamics (CD2024), 26-30 August 2024, Ruhr University Bochum, Germany. 15 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Quantum Physics (quant-ph)
arXiv:
2503.23233 [pdf]
PoS(2026)·3 citations
06
[Submitted on 30 Mar 2025]
Neutron stars and Constraints for the Equation of State of Dense Matter
Rajesh Kumar · Veronica Dexheimer · Johannes Jahan
Neutron stars provide a natural laboratory for studying the properties of dense nuclear matter under extreme conditions. In this proceeding, we review our current understanding of dense isospin symmetric and asymmetric matter and neutron star physics. We focus on modern theoretical, experimental, and observational constraints, including first-principle calculations from lattice and perturbative Quantum Chromodynamics (QCD), as well as chiral effective field theory approaches at nuclear densities. From the experimental perspective, constraints on the equation of state arise from heavy-ion collisions, low-energy nuclear physics, and astrophysical observations, including neutron star masses, radii, and gravitational wave signatures from mergers. These multidisciplinary comparisons are crucial for bridging the gap between nuclear physics and astrophysical observations, in order to expand our knowledge of matter at supra-nuclear densities.
Comments:
15 pages, 2 figures, Conference Proceeding
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat)
arXiv:
2503.23413 [pdf]
PoS(2025)·2 citations
07
[Submitted on 30 Mar 2025]
Bayesian method for quantifying the non-Gaussian fluctuations in low-intermediate energy heavy ion collisions
Xinyu Wang🇨🇳 · Xiang Chen🇨🇳 · Junping Yang🇨🇳 · Ying Cui🇨🇳 · Zhuxia Li🇨🇳 · Kai Zhao🇨🇳 · Yingxun Zhang🇨🇳
In this work, we present a model-independent method to quantify the non-Gaussian fluctuations in the observable distributions, which are assessed by the difference between the measured observable distributions and reconstructed observable distributions via the Bayesian method. Our results indicate that the strength of non-Gaussian fluctuation increases with the beam energy, and is primarily driven by non-central collision mechanisms. The experimental measurement of the strength of non-Gaussian fluctuation of the observable distributions will provide valuable insights into understanding the nonequilibrium effects in heavy ion collisions and the liquid-gas phase transition in finite nuclei.
Comments:
6 pages, 4 figures, published on PLB
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2503.23417 [pdf]
PLB(2025)·0 citations
08
[Submitted on 30 Mar 2025]
Pfaffian formulas for non equivalent bases
L.M. Robledo
Pfaffian formulas used to compute overlaps necessary to carry out generator coordinate method calculations using a set of Hartree- Fock- Bogoliubov wave functions, is generalized to the case where each of the HFB states are expanded in different arbitrary bases spanning different sub-space of the Hilbert space. The formula obtained is compared with previous results proving to be completely equivalent to them. A discussion of equivalent formulas obtained in the literature is carried out.
Comments:
5 pages, no figures
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el)
arXiv:
2503.23539 [pdf]
PLB(2025)·2 citations
09
[Submitted on 31 Mar 2025]
Nuclear clustering process in heavy-ion collisions : experimental constraints on the low-temperature region of the QCD phase diagram
E. Bonnet🇫🇷 · B. Borderie🇫🇷 · R. Bougault🇫🇷 · A. Chbihi🇫🇷 · Q. Fable🇫🇷 · J.D. Frankland🇫🇷 · D. Gruyer🇫🇷 · M. La Commara🇮🇹 · A. Le Fèvre🇩🇪 · N. Le Neindre🇫🇷 · I. Lombardo🇮🇹 · J. Łukasik🇵🇱 and 3 other authors
In this article, we study the production of Hydrogen and Helium isotopes in heavy-ion collisions in the incident energy range between 80 and 150 MeV/nucleon. We compare their inclusive multiplicities emitted in the transverse plane of the reaction with the predictions given by the thermal model. As a first step, we validate the choice of this approach to describe the experimental measurements. We also show that the transient states have to be explicitly taken into account for a good statistical description of the experimental multiplicities. From the thermodynamical parameter values obtained we complete the existing database built with the use of thermal-statistical models to reproduce particle production in the (ultra-)relativistic-energy measurements. We then proposed a new constraint on the so-called freeze-out region in the temperature (T) versus baryonic chemical potential (muB) phase diagram of the quantum chromodynamics. These new results indicate that there is a common framework to describe the hadron production and nuclear clustering processes in heavy-ion collisions.
Comments:
10 pages, 3 figure panels, accepted for publication in PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2503.23809 [pdf]
PRC(2025)·4 citations
10
[Submitted on 31 Mar 2025]
Investigating nuclear beta decay using lattice quantum Monte Carlo approach
Teng Wang🇨🇳 · Xu Feng🇨🇳 · Bing-Nan Lu🇨🇳
We present an \textit{ab initio} calculation of nuclear $β$ decay within the framework of nuclear lattice effective field theory (NLEFT), employing auxiliary-field quantum Monte Carlo methods to solve the nuclear many-body problem. Our approach combines next-to-next-to-leading order two- and three-body chiral interactions with one- and two-body axial current operators, all consistently derived in chiral effective field theory. Low-energy constants are determined exclusively from nucleon-nucleon scattering phase shifts and few-body observables for systems with $A \leq 3$ . Using these interactions and transition operators, we perform two-channel Monte Carlo simulations to compute the $β$ -decay matrix element for $^{6}$ He, obtaining results in reasonable agreement with experimental measurements. To address the Monte Carlo sign problem, we implement a perturbative expansion around a leading-order Hamiltonian with approximate Wigner-SU(4) symmetry. This systematic approach provides a foundation for extending NLEFT simulations to precision studies of weak processes in medium-mass nuclei.
Comments:
10 pages, 4 figures, with 3 pages of supplemental materials. Accepted for publication in PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat)
arXiv:
2503.23840 [pdf]
PRC(2025)·8 citations
11
[Submitted on 31 Mar 2025]
Time-Dependent Density Functional Theory Description of $^{238}$ U(n,f), $^{240, 242}$ Pu(n,f) and $^{237}$ Np(n,f) Reactions
Aurel Bulgac · Ibrahim Abdurrahman · Matthew Kafker · Ionel Stetcu
In nuclei with an odd nucleon number the non-vanishing spin number density is the source of a pseudo-magnetic field, which favors the splitting of the nucleon Cooper pairs. Such an pseudo-magnetic field is generated always in the dynamics of any nucleus, but its effects on Cooper pairs is significantly enhanced in the dynamic evolution of nuclei with an odd number of nucleons. We present for the first time a microscopic study of the induced fission of the odd neutron compound nuclei $^{239}$ U, $^{241, 243}$ Pu, and the odd proton, odd neutron compound nucleus $^{238}$ Np, performed within the time-dependent density functional theory extended to superfluid fermion systems, without any simplifying assumptions and with controlled numerical approximations, and for a very large number of initial conditions. Due to the presence of the unpaired odd nucleon(s), the time-reversal symmetry of the fission compound nucleus is spontaneously broken, an aspect routinely neglected in the most advanced microscopic approaches of the past. The emerging fission fragment properties are quite similar to the properties of fission fragments of neighboring even-even nuclei. The time from saddle-to-scission is often significantly longer in odd-N-odd-Z or odd-A nuclei than for even-even nuclei since systems with unpaired nucleons are easier to excite and the potential energy surfaces of these nuclei have more structure, often resembling a very complicated obstacle course, rather than a more direct evolution of the nuclear shape from the top of the outer fission barrier to the scission configuration. The Pauli blocking approximation, often invoked in the literature, expected to inhibit the fission of nuclei with unpaired nucleons, is surprisingly strongly violated during the fission dynamics.
Comments:
5 pages, 5 figures, 1 table
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2503.24268 [pdf]
PRL(2025)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE