Nuclear Theory·nucl-th

Monday·June 2, 2025

8 papers—5 primary·3 cross-listed

01
[Submitted on 29 May 2025]
AI-Assisted analysis of $^{28}$ Si $^{*}$ $\to$ 7 $α$ break-up data
Theodoros Depastas🇺🇸 · Aldo Bonasera🇺🇸 · Joe Natowitz🇺🇸
Mid-weight $α$ -conjugate nuclei are predicted to possess exotic toroid-like resonances with high angular momenta. The search for these states in $^{28}$ Si $^{*}$ is the main point of two published experimental investigations of the peripheral $^{28}$ Si + $^{12}$ C reaction by Cao and collaborators and by Hannaman and collaborators. In this work, we develop a novel Artificial Intelligence (AI)-based machine learning method utilizing the Gaussian Mixture Model (GMM) to analyze available experimental and theoretical data. We additionally study the reaction with the Hybrid $α$ -Cluster (H $α$ C) model. In all the examined data our results suggest the presence of underlying structure which is close to that predicted for toroidal states.
Comments:
9 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.23920 [pdf]
PRC(2025)·3 citations
02
[Submitted on 30 May 2025]
Radial and Non-Radial Oscillations of Protoneutron Stars with Hyperonic Composition
Prashant Thakur🇮🇳 · Adamu Issifu🇧🇷 · Ishfaq Ahmad Rather🇩🇪 · Y. Lim🇰🇷 · Tobias Frederico🇧🇷
This paper explores radial and non-radial oscillations of protoneutron stars (PNSs) as they evolve from hot, neutrino-rich configurations through deleptonization to cold, catalyzed states. The equation of state (EoS) is modeled using a density-dependent relativistic mean-field framework, with stellar evolution characterized by changes in entropy and lepton fraction. Both nucleonic and hyperonic compositions are considered. Non-radial $f$ - and $p_{1}$ -mode oscillations are computed using both the Cowling approximation and the full General Relativistic framework. Trapped neutrinos initially increase the error in the Cowling approximation for $f$ -modes, which decreases during deleptonization and rises again in the cold phase. In contrast, $p_{1}$ -mode errors peak during intermediate stages due to evolving pressure and density gradients. The emergence of hyperons modestly raises oscillation frequencies in both modes. Existing universal relations for $f$ -mode frequency and damping time lack model independence for PNSs, motivating a more robust relation. In particular, our proposed universal relation involving the moment of inertia and $η ~$ shows strong agreement across all evolutionary phases, offering a temperature-sensitive, model-independent scaling for asteroseismology. Radial oscillations of a $1.4 M_{⊙}$ PNS are also studied for different EoSs. Our results show that displacement ( $ξ$ ) and pressure perturbation ( $η$ ) profiles are highly sensitive to thermal state, composition, and compactness. Hyperonic stars show higher frequencies, altered node structures, and stronger pressure perturbations due to EoS softening. Differences in frequency separation $Δ ν_{n}$ and fundamental frequency $ν_{0}$ between nucleonic and hyperonic models provide clear observational diagnostics for probing the interiors of PNSs and constraining the EoS of dense matter.
Comments:
18 pages, 11 figures, 6 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2505.24104 [pdf]
EPJC(2026)·6 citations
03
[Submitted on 30 May 2025]
Next-to-leading-order prediction for the neutrinoless double-beta decay
Y. L. Yang🇨🇳 · P. W. Zhao🇨🇳
The neutrinoless double-beta decay ( $0 ν β β$ ) of two neutrons $nn \to pp ee$ is the elementary subprocess of $0 ν β β$ decay in nuclei. Accurate knowledge of the $nn \to pp ee$ amplitude is required to pin down the short-range contributions in the nuclear matrix elements of the candidate nuclei for large-scale $0 ν β β$ searches. In this Letter, we report the first next-to-leading-order prediction of the nn \rightarrow ppee amplitude, with Bayesian uncertainty quantification. This is made possible by the development of the relativistic chiral effective field theory, in which no unknown contact term is required up to next-to-leading order. The theory is validated by reproducing in a parameter-free way the available data on the charge independence and charge symmetry breaking contributions in the two-nucleon scattering. The present work makes an essential step towards addressing the uncertainty in the theoretical calculations of the nuclear matrix elements relevant for $0 ν β β$ searches.
Comments:
6 pages, 5 figures, accepted by Physical Review Letters
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2505.24121 [pdf]
PRL(2025)·4 citations
04
[Submitted on 30 May 2025]
Neutrino emission from neutron star matter
Omar Benhar🇮🇹 · Lucas Tonetto🇮🇹
The temperature of a newly formed neutron star is believed to be as high as $1 0^{11}$ ~K, corresponding to a thermal energy of about $10$ MeV. After a time $t \sim 50 s$ , the neutrino mean free path in nuclear matter exceeds the typical star radius, R~ $\sim$ ~10 Km, and neutrino emission becomes the dominant mechanism of energy loss, eventually bringing the temperature down to $\sim 1 0^{8}$ ~K. Neutrinos also play a critical role in determining the composition of matter in the star interior, consisting primarily of a charge-neutral mixture of neutrons, protons and leptons in $β$ -equilibrium. This article provides an introduction to the weak interactions of nucleons in nuclear matter, as well as a concise review of the neutrino emission reactions taking place in the neutron star core. The approximations involved in the standard theoretical treatment of thermal and dynamical effects are analysed in the light of the recent progress of the field, and the prospects for future developments are outlined.
Comments:
Invited paper, accepted for publication in IJMPE
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.24485 [pdf]
IJMPE(2025)·2 citations
05
[Submitted on 30 May 2025]
Heavy Ion Double Charge Exchange Reactions as Probes for Two-Body Transition Densities
Jessica I.Bellone · Maria Colonna · Danilo Gambacurta · Horst Lenske
Collisional heavy ion double charge exchange (DCE) reactions, induced by second order nucleon-nucleon interactions, are shown to provide access to the two-body transition densities of the complementary DCE transitions in the interacting nuclei. Corresponding two-body operators are introduced, treating the second order distorted wave reaction amplitude in the s-channel interaction form. The theoretical results are applied to the reaction $^{18} O +^{76} S e \to^{18} N e +^{76} G e$ at $T_{l ab} = 270$ ~MeV, being $^{76} G e$ a candidate for neutrino--less double beta decay.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2505.24753 [pdf]
PRC(2025)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE

AI-Assisted analysis of 28Si∗ → 7α break-up data

Radial and Non-Radial Oscillations of Protoneutron Stars with Hyperonic Composition

Next-to-leading-order prediction for the neutrinoless double-beta decay

Neutrino emission from neutron star matter

Heavy Ion Double Charge Exchange Reactions as Probes for Two-Body Transition Densities

Affiliations

AI-Assisted analysis of $^{28}$ Si $^{*}$ $\to$ 7 $α$ break-up data