We present a framework for spin dynamics in the quark-gluon plasma created in relativistic heavy-ion collisions. Under the approximation of small polarization, macroscopic spin degrees of freedom decouple from the background, and their evolution equations and transport coefficients have been computed using quantum kinetic theory of massive particles with nonlocal collisions. Employing this theory, we numerically solve dissipative relativistic spin hydrodynamics. We explore three interaction scenarios between constituent particles and apply this framework to compute both global and local spin polarization of $\mathrm{\Lambda }$ hyperons in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}}=200$ GeV. Our results show that the initially vanishing spin potential relaxes toward thermal vorticity, driving global polarization. Furthermore, we demonstrate that the sign of longitudinal polarization is sensitive to the interaction type, emphasizing the need for a consistent treatment of dissipative effects in spin hydrodynamics to describe experimental data.

The ${}^{32}\mathrm{Si}{(}^3\mathrm{He},\mathit{d}){}^{33}\mathrm{P}$ reaction was studied in inverse kinematics at $6.3\mathrm{MeV}/u$. States in ${}^{33}\mathrm{P}$ corresponding to the proton $1s\text{−}0d$ single-particle orbitals were identified up to $\approx 4.5$ MeV in excitation energy. The (${}^3\mathrm{He},d$) spectroscopic factors were determined from distorted-wave Born approximation calculations. When combined with complementary neutron-adding data, the $1s\text{−}0d$ proton vacancies in the ${}^{32}\mathrm{Si}$ ground state were extracted. In conjunction with a reanalysis of data from previous single-particle measurements, the trends in proton and neutron vacancy were explored across the ${}^{28,30,32,34}\mathrm{Si}$ isotopes. Both proton and neutron vacancy data show gradual changes in their occupancies. The proton $1s_{1/2}$ orbitals in ${}^{32}\mathrm{Si}$ and ${}^{34}\mathrm{Si}$ are both consistent with being empty. The ground-state nucleon distributions are described by shell-model calculations constrained to the $1s\text{−}0d$ model space.

The study of neutron-induced threshold reactions is important for validating nuclear models, ensuring accuracy in theoretical frameworks, and finding practical applications, particularly in fusion reactor technology (FRT) and accelerator-driven systems (ADSs). This research focuses on measuring neutron-induced reaction cross sections on ${}^{68}\mathrm{Zn}$, specifically the ${}^{68}\mathrm{Zn}{(n,p)}^{68}\mathrm{Cu}$ and ${}^{68}\mathrm{Zn}{(n,\alpha )}^{65}\mathrm{Ni}$ reactions. Current data for these reactions are limited in the case of the ($n,p$) reaction, and in the case of the ($n,\alpha$) reaction exhibit significant discrepancies, especially for the neutron energy range below 12 MeV. Our study addresses these data gaps and discrepancies by providing new cross-section measurements. To address these gaps, we performed new cross-section measurements using white neutron beams at the Weapons Neutron Research (WNR) facility at Los Alamos Neutron Science Center (LANSCE), contributing to a more detailed understanding of neutron-induced reactions on ${}^{68}\mathrm{Zn}$ below 20 MeV. The experimental setup, data analysis, and results are discussed, highlighting the improved agreement between our new data and theoretical calculations.

A systematic study of all relevant in-medium effects on the total $K^{-}$ nuclear potential is presented in this work. The $K^{-}N$ scattering amplitudes, including Pauli-blocking effects and hadron self-energies (hyperons, nucleons, pions, and kaons), are derived within a next-to-leading-order chiral meson-baryon coupled-channel interaction model. These amplitudes are employed in a microscopic model of the $K^{-}$ nuclear potential in symmetric nuclear matter that includes one-, two-, and, when the kaons and pions are dressed, also multinucleon absorption processes. The potential is then applied in calculations of the strong energy shifts and widths of 64 measured kaonic atom levels. The comparison of the results of the full model that includes Pauli correlations and hadron self-energies with data provides ${\chi }^2/dp=1.5$, the lowest value obtained by a theoretical model to date and comparable with that of the best fitted phenomenological potentials. Furthermore, the calculated branching ratios for mesonic and nonmesonic absorption channels in kaonic carbon and kaonic neon are in good agreement with available data.

The fundamental process of neutrinoless double β decay, $nn\to pp{e}^{-}{e}^{-}$, dominated by the exchange of light Majorana neutrinos, is studied in a quasiphenomenological framework based on chiral effective field theory. In the current calculation, we evaluate the contributions of finite nucleon size to the transition amplitude in a nonperturbative manner by incorporating the nucleon form factors. We find that the present approach could renormalize the amplitude in the context of the standard mechanism and provide predictions consistent with the previous investigations. Consequently, we argue that the physics parametrized by the form factors is related to that of the leading-order contact term introduced in [V. Cirigliano et al., Phys. Rev. Lett. 120, 202001 (2018)]. in a perturbative scheme. To solidify our calculation, we also perform nuclear many-body calculations for finite nuclei ${}^{76}\mathrm{Ge}$ and ${}^{136}\mathrm{Xe}$. Our results provide not only a benchmark calculation for the transition amplitude between two frameworks but also evidence for the reasonableness of nonperturbative treatment for the effects of finite nucleon size in conventional nuclear many-body methods.

In the coming age of precision neutrino physics, neutrinos from the Sun become robust probes of the conditions of the solar core. Here, we focus on ${}^8\mathrm{B}$ neutrinos, for which there are already high-precision measurements by the Sudbury Neutrino Observatory and Super-Kamiokande. Using only basic physical principles and straightforward statistical tools, we estimate projected constraints on the temperature and density of the ${}^8\mathrm{B}$ neutrino production zone compared to a reference solar model. We outline how to better understand the astrophysics of the solar interior using forthcoming neutrino data and solar models. Finally, we note that detailed forward modeling will be needed to develop the full potential of this approach.

Reference-state-based many-body methods start from Hamiltonians that are normal ordered with respect to the reference state. In low-energy nuclear physics applications, normal-ordered Hamiltonians consisting of two- and three-nucleon forces are usually truncated at the two-body rank with residual three-nucleon operators being discarded. Benchmark computations have shown that this truncation is accurate, but we lack an understanding about why it works. We show that the normal-ordered two-body truncation is exact for zero-range three-body forces when nuclei are computed using the coupled cluster with singles and doubles method. As the nuclear three-nucleon force is short ranged and a three-body contact is a leading term in effective field theories of quantum chromodynamics, our result provides an analytical basis for the popular normal-ordered two-body approximation.

A unified description of full reaction channels in low-energy heavy-ion collisions is a great challenge. Although, the theoretical models based on the dinuclear system (DNS) concept have been successfully employed in multinucleon transfer (MNT) reactions, the underestimation of the quasielastic (QE) channel results in unreliable description of few-nucleon transfer, especially for the light reaction systems. In this work, the DNS-sysu model is improved by introducing the impact-parameter-dependent transition probabilities for a unified description of few-nucleon and many-nucleon transfer in MNT reactions. Extensive experimental data—including reactions such as ${}^{40}\mathrm{Ca}$, ${}^{58,64}\mathrm{Ni}$, ${}^{136}\mathrm{Xe}$, and ${}^{208}\mathrm{Pb}+{}^{208}\mathrm{Pb}$—were compared with the model predictions. The calculated isotopic distributions, mass distributions, and charge distributions show good agreement with experimental measurements. The improved DNS-sysu model enables reasonable characterization and description of the QE scattering or grazing collision, notably resolving long-standing underestimation in the QE channel.

We present the measured data of the proton analyzing power $A_y$ in polarized proton elastic scattering of an unpolarized ${}^3\mathrm{He}$ target and the ${}^3\mathrm{He}$ analyzing power $A_{0y}$ in unpolarized proton scattering of a polarized ${}^3\mathrm{He}$ target at three intermediate energies: 50, approximately 65, and 100 MeV. The experimental results are compared with rigorous four-nucleon scattering calculations based on the realistic charge dependent (CD) Bonn nucleon-nucleon ($NN$) potential. Large discrepancies are observed for both $A_y$ and $A_{0y}$ at the angles where the observables exhibit a minimum and a maximum at almost all three measured energies. The examination for discrepancies has been extended to the lower incident energy of 8.5 MeV, revealing that differences exist from 8.5 to 100 MeV for $A_y$. The $\mathrm{\Delta }$-isobar effects derived using the $NN+N\mathrm{\Delta }$ coupled-channel approach do not account for the $A_y$ and $A_{0y}$ data at the three investigated energies. We therefore estimated the effects of the irreducible three-body forces associated with the CD $\mathrm{Bonn}+\mathrm{\Delta }$-isobar calculations. We also analyzed the $p\text{−}{}^3\mathrm{He}$ elastic scattering amplitudes. The results obtained suggest that $A_y$ and $A_{0y}$ for $p\text{−}{}^3\mathrm{He}$ elastic scattering at intermediate energies are insensitive to the $2\pi$-exchange-type three-nucleon forces ($3N\mathrm{Fs}$), but enhance nuclear interactions, including the $3N\mathrm{Fs}$ masked in nucleon-deuteron elastic scattering.

This study presents a unified theoretical analysis of $\alpha$, simultaneous $2\alpha$, and heavier cluster emissions from a series of actinium (Ac) and thorium (Th) isotopes in the mass ranges ${}^{207–229}\mathrm{Ac}$ and ${}^{210–230}\mathrm{Th}$, within the framework of preformed cluster model (PCM). The emphasis is focused on identifying and characterizing the rare yet physically significant, $2\alpha$ decay mode, treated as the simultaneous emission of two $\alpha$ particles from the parent nucleus. The study aims to understand the isotopic evolution of decay modes, particularly the transition from dominant $\alpha$ decay to the emergence of simultaneous $2\alpha$ and the heavier cluster emissions. The model incorporates detailed computations of $Q$ values, barrier penetrabilities, and cluster preformation probabilities to systematically assess the viability of various decay channels. Through this approach, we aim to understand the structural and dynamical conditions that prefer the simultaneous $2\alpha$ emission and identify specific isotopes where such processes become increasingly probable. The even-odd staggering observed in reference to the calculated decay half-lives and preformation probabilities reflects the underlying nuclear structure effects and pairing correlations, offering additional insight into decay dynamics. Moreover, the Geiger-Nuttall plots constructed for both $\alpha$ and $2\alpha$ modes confirm linear systematics, validating the quantum tunneling nature of these emissions. The present work not only extends the applicability of PCM to rare decay modes but also provides a theoretical basis for future experimental validations related to rare decay mechanisms of radioactive nuclei.

In this paper, we make use of transition sum rules to study isoscalar and isovector pairing correlations in $T=0$ states of seven self-conjugate nuclei, ${}^{96}\mathrm{Cd}$, ${}^{94}\mathrm{Ag}$, ${}^{92}\mathrm{Pd}$, ${}^{90}\mathrm{Rh}$, ${}^{48}\mathrm{Cr}$, ${}^{46}\mathrm{V}$, and ${}^{44}\mathrm{Ti}$. Four typical pairing correlation schemes are investigated, including (i) isoscalar spin-aligned (SA), (ii) isoscalar spin-one (SO), (iii) isovector lowest-seniority (LS), and (iv) isovector $SDG$ pair approximations. Our systematic calculations demonstrate that the SA pairing strongly suppresses Gamow-Teller transitions, while the SO pairing reduces electric quadrupole transition strengths. Comparisons with experimental data show that the SA pairing picture accurately describes high-spin isomers with relatively long half-lives, whereas the isovector pairing (LS/$SDG$) modes is more favored by low-spin ground states. In addition, we investigate the robustness of these conclusions by extending our calculations from single-$j$ to multi-$j$ shells with realistic shell-model interactions.

Background: The Maxwellian average cross section (MACS) is usually calculated with help of the statistical codes that do not take into account fluctuations of individual resonance parameters. The actual MACS can substantially deviate from its expectation value.

Purpose: This work focuses on description of various sources and aspects of these fluctuations.

Methods: Simulated resonance sequences considering all the fluctuations involved in the statistical model are used for this purpose. Contribution of various sources of the fluctuations and neutrons with different orbital momenta are thoroughly investigated and described. Impact of available cross-section data at low neutron energies is also checked.

Results: Based on this analysis simple empirical formulas for estimating relative fluctuations of MACS using solely $s$-wave resonance spacing $D_0$ and the temperature of the stellar environment are derived. It is shown that real nuclei follow the proposed formula well.

Conclusions: The expected MACS fluctuations increase with $D_0$ and can be significant. While for isotopes with $D_0$ in the eV range the possible deviation from calculated values are small, for nuclei with $D_0$ in the keV range the full-width half-maximum of the expected distribution is larger than about 25% and 10% for astrophysically relevant temperatures of $kT=8$ and 30 keV. At least for these nuclei the predictions from statistical codes must be taken with caution.

The chiral magnetic effect (CME) is a phenomenon in which electric charge is separated by a strong magnetic field from local domains of chirality imbalance and parity violation in quantum chromodynamics. The CME-sensitive observable, the charge-dependent three-point azimuthal correlator $\mathrm{\Delta }\gamma$, is contaminated by a major physics background proportional to the particle's elliptic flow anisotropy $v_2$. Event-shape engineering (ESE) binning events in dynamical fluctuations of $v_2$ and event-shape selection (ESS) binning events in statistical fluctuations of $v_2$ are two methods to search for the CME by projecting $\mathrm{\Delta }\gamma$ to the measured anisotropy $v_2=0$ intercept. We conduct a systematic study of these two methods using physics models as well as toy model simulations. It is observed that the ESE method fulfills the general premise of measuring the CME but is statistically hungry. It is found that the intercept from the ESS method depends on the details of the event content, such as the mixtures of background-contributing sources, because of statistical fluctuations of intertwining variables used in the method, and is thus not practically useful to measure the CME.

Relativistic heavy ion collisions provide a unique opportunity to probe the nuclear structure by taking an instantaneous snapshot of the colliding nuclei and converting it into momentum anisotropies of final emitted hadrons. A long-standing puzzle of too large a ratio of the elliptical-to-triangular ($v_2$-to-$v_3$) anisotropies in ultracentral ${}^{208}\mathrm{Pb}+{}^{208}\mathrm{Pb}$ collisions at the Large Hadron Collider (LHC) cannot be solved simply by hydrodynamic simulations with initial conditions containing the spherical or certain deformed shape of ${}^{208}\mathrm{Pb}$. In this Letter, using the iEBE-VISHNU relativistic viscous hydrodynamic hybrid model simulations with the ${\mathrm{T}}_{\mathrm{R}}\mathrm{ENTo}$ initial condition, we show that a dynamic octupole deformation—a shape-breathing mode of ${}^{208}\mathrm{Pb}$—could potentially solve the $v_2$-to-$v_3$ puzzle and simultaneously describe the $v_3\left\{4\right\}$ data measured in experiment. Our results highlight the unique capability of capturing transient collective properties of nuclei on yoctosecond (${10}^{-24}$ s) timescales, unfeasible with low-energy nuclear reactions.

In the nova temperature range, 0.1 GK $<T<$ 0.4 GK, several low-energy resonances dominate the ${}^{21}\mathrm{Ne}(p,\gamma ){}^{22}\mathrm{Na}$ reaction rate, which is currently affected by large uncertainties. We present a high-precision study of the resonances at $E_{\mathrm{r}}^{\mathrm{lab}}=127.3$, 271.4, 272.3, 291.5, and 352.6 keV, measured directly at the Laboratory for Underground Nuclear Astrophysics in Italy. The strengths of the 127.3-, 271.4-, and 291.5-keV resonances are consistent with previous measurements within $1\sigma$. However, for the 272.3- and 352.6-keV resonances, we report strength values of (129.9 $\pm$ 5.8) meV and (14.9 $\pm$ 0.8) meV, respectively, more than a factor of 1.5 higher than literature values. In addition, we report on new branching ratios for the 127.3-, 272.3-, and 352.6-keV resonances, leading to updated decay schemes. Finally, we present a revised thermonuclear reaction rate and investigate its impact on the NeNa nucleosynthesis.

Based on the Boltzmann-Uehling-Uhlenbeck equation, we investigate the effects of the isovector nucleon effective mass $m_{v,0}^{*}$ and the in-medium nucleon-nucleon cross section ${\sigma }^{*}$ on the isovector giant dipole resonance (IVGDR) in ${}^{208}\mathrm{Pb}$, employing a set of representative Skyrme energy density functionals. We find that the energy-weighted sum rule $m_1$ of the IVGDR is highly sensitive to $m_{v,0}^{*}$ and only mildly dependent on ${\sigma }^{*}$, while the width $\mathrm{\Gamma }$ of the IVGDR is primarily governed by ${\sigma }^{*}$ with a moderate sensitivity to $m_{v,0}^{*}$. From a Bayesian analysis of both $m_1$ and $\mathrm{\Gamma }$, we infer that the $m_{v,0}^{*}/m$ = $0.{730}_{-0.034}^{+0.036}$, where $m$ is the bare nucleon mass. Furthermore, by incorporating the isoscalar nucleon effective mass $m_{s,0}^{*}/m=0.820\pm 0.030$, extracted from the isoscalar giant quadrupole resonance in ${}^{208}\mathrm{Pb}$, the linear neutron-proton effective mass splitting coefficient at saturation density ${\rho }_0$ is determined to be $\mathrm{\Delta }{m}_1^{*}\left({\rho }_0\right)/m=0.{202}_{-0.114}^{+0.118}$.

The cluster structures of the $0^{+}$ states in ${}^{12}\mathrm{C}$, including the ground state, the Hoyle state, and the recently identified $0_3^{+}$ and $0_4^{+}$ states, are analyzed to explore the cluster configurations and $3\alpha$ correlations without assuming the existence of ${}^8\mathrm{Be}$. In particular, the key quantity—two-cluster overlap amplitudes—is calculated for $3\alpha$ clustering channels to reveal the essential features of these $0^{+}$ states. The results clearly show the distinction between the compact structure of the ground state and the gas-like structures of the excited $0^{+}$ states. The Hoyle state exhibits the expected gas-like dominant $\left(0S\right)$ configuration, while the $0_3^{+}$ state shows a more extended $3\alpha$ clustering structure, which can be viewed as a breathing-mode excitation of the Hoyle state. The $0_4^{+}$ state is found to have a mixed configuration, featuring a bent-arm-like structure in the $S\otimes S$ channel and an enhanced $2\alpha$ correlation in the $D\otimes D$ channel.