Results of decay studies of nuclei in the vicinity of ${}^{54}\mathrm{Zn}$, which is the most neutron-deficient isotope of zinc and undergoes ground-state two-proton radioactivity (2p), are presented. The measurements were performed with a gaseous time-projection chamber with optical readout, which allowed us to record tracks of protons emitted in the decays. A new method of data analysis was used to reconstruct energies and emission angles of low-energy protons that were stopped within the active volume of the chamber. Half-lives and branching ratios for $\beta$-delayed proton emission channels were determined for ${}^{56}\mathrm{Zn}, {}^{55}\mathrm{Zn}$, and ${}^{55}\mathrm{Cu}$. The $\beta$-delayed emission of two protons for ${}^{55}\mathrm{Zn}$ was observed for the first time. Five events of 2p radioactivity of ${}^{54}\mathrm{Zn}$ were detected and reconstructed. The distribution of the opening angle between momenta of the two protons is consistent with the findings published by Ascher et al. [Phys. Rev. Lett. 107, 102502 (2011)].

To study the structure and stability of the isotopes ${}^{295–304}120$, the self-consistent Hartree-Fock-Bogoliubov calculations are performed using the Skyrme-SLy4 energy-density functional and a zero-range pairing interaction, regularized to avoid divergences. The ground-state deformation evolves from prolate to oblate near $N=174$, with shape coexistence, before the oblate deformation vanishes at $N=182$. The fission barriers increase by a few MeV driven by enhanced shell effects near the $N=184$ and $Z=120$ shell closures. The energy of the rotational $2^{+}$ state reaches a minimum near $N=170$, then it rises as deformation decreases. For consistency, $\alpha$-decays into ground and excited states are analyzed within the preformed cluster model using the nucleus-nucleus potential derived from the same energy-density functional, combining Wentzel-Kramers-Brillouin penetrability and assault frequency. Predicted half-lives range from ms for ${}^{300,302}120$ and ${}^{296,298}\mathrm{Og}$ to an order of ${10}^2\mathrm{s}$ for ${}^{292}\mathrm{Fl}$, with a significant population the $2^{+}$ state in the daughter nuclei of ${}^{296}120, {}^{292,294}\mathrm{Og}, {}^{288,294}\mathrm{Lv}$, and ${}^{286}\mathrm{Fl}$.

We compute nuclear response functions by solving the time-dependent $A$-body Schrödinger equation, recording the time-dependent transition moment and extracting spectral information via Fourier transforms. The solution of the time-dependent many-body problem accounts for correlations on top of the mean field by taking advantage of a time-dependent formulation of coupled-cluster theory. As a validation, we focus on electric dipole transitions in ${}^4\mathrm{He}$ and ${}^{16}\mathrm{O}$ and compare moments of the response function distribution to the results of an equivalent static framework, finding negligible discrepancies. We investigate how proton and neutron densities evolve in time, and we see the traditional picture of soft and giant dipole resonances as collective oscillations of protons and neutrons emerging from our calculations in ${}^{16}\mathrm{O}$ and ${}^{24}\mathrm{O}$. This method also allows us to investigate the behavior of the nucleus in the presence of a strong electric field. In that regime, the behavior of the system becomes chaotic. Qualitatively, the spectral information obtained in this limit is in line with previous time-dependent mean-field results.

Chirality is a distinct signature that characterizes triaxial shapes in nuclei. We report the first observation of chirality in the nucleus ${}^{135}\mathrm{Pr}$ using a high-statistics Gammasphere experiment with the ${}^{123}\mathrm{Sb}({}^{16}\mathrm{O},4n){}^{135}\mathrm{Pr}$ reaction. Two chiral-partner bands with the configuration $\pi {\left(1h_{11/2}\right)}^1\otimes \nu {\left(1h_{11/2}\right)}^{-2}$ have been identified in this nucleus. Angular distribution analyses of the $\mathrm{\Delta }I=1$ transitions connecting the two bands reveal a dominant dipole character, and quasiparticle triaxial rotor model calculations show good agreement with the data. Since the simultaneous observation of chirality and transverse wobbling in ${}^{135}\mathrm{Pr}$ relies critically on these angular distribution results, we also address and refute the experimental and theoretical criticisms raised in a recent work by Lv et al., presenting additional evidence that further strengthens our interpretation. This marks the first observation of both hallmarks of triaxiality—chirality and wobbling—in the same nucleus.

Caloric curve for quasiprojectile (QP) particles is investigated, using the INDRA data set of $\mathrm{Xe}+\mathrm{Sn}$ at 50 MeV/u. A constant pressure condition is applied, approximated by the isotropic expansion of the QP source with a constant velocity, but neither limiting temperature nor backbending behavior is observed in the extracted caloric curves. The extracted caloric curves follow a theoretical curve from the Fermi gas model with a level density parameter of $a=13$. ${}^3\mathrm{He}$ and $\alpha$ particles show much higher temperature values than those of the Hydrogen isotopes. The dynamical origin of the high energy light charged particles in the QP source is investigated and it is found that they are associated with the intermediate mass fragment production at the midrapidity in midperipheral to peripheral collisions. This component likely washes away the characteristic features of the liquid-gas phase transition, such as limiting temperature and backbending behaviors, in the caloric curves extracted in this study.

The octet and decuplet $SU{\left(3\right)}_f$ baryons are studied with the Polyakov, Nambu, and Jona-Lasinio model, in a diquark-quark approach, via the resolution of the Bethe-Salpeter equation. This work includes estimations of their masses according to the temperature and the baryonic density, with or without the isospin symmetry. Several improvements of this modeling are proposed and tested: the treatment of the baryons' unstable regime, the inclusion of the diquark momentum dependence, the possibility to model baryons without the static approximation, the description of the octet baryons via scalar and axial flavor components, and the use of a Nambu and Jona-Lasinio diquark propagator instead of a structureless one. The effects of the color superconductivity on the nucleon mass are also investigated. Certain of the mentioned improvements can be applied simultaneously. The advantages and limitations of each of them are highlighted.

Lifetimes of low-lying states in the yrast $\nu i_{13/2}$ band in ${}^{165}\mathrm{W}$ have been measured using the recoil distance Doppler-shift (RDDS) method. The excited states of interest were populated in the ${}^{92}\mathrm{Mo}$(${}^{78}\mathrm{Kr},4p1n$)${}^{165}\mathrm{W}$ fusion-evaporation reaction and their decays were investigated via $\gamma$ rays detected in the Jurogam II detector array in coincidence with nuclei separated and detected using the RITU gas-filled separator. From the experimental lifetimes, corresponding reduced transition strengths, $B$($E2$) values, were deduced and an unusually low experimental value of the ratio $\frac{B(E2;21/2^{+}\to 17/2^{+})}{B(E2;17/2^{+}\to 13/2^{+})}=0.59\left(7\right)$ was extracted, similar to what has been observed in neighboring nuclei in this mass region. The experimental results have been compared with Woods-Saxon-type mean field and interacting boson-approximation (IBM-1) calculations.

A Bayesian neural network (BNN) framework is established to probe the nuclear symmetry energy coefficient $C_{\mathrm{sym}}$ through isoscaling analysis of spallation fragments produced in proton-induced reactions on Ca, Ni, and Xe isotopic targets. The reliability of BNN predictions is preliminarily validated against available experimental data and empirical systematics. Systematic analysis reveals that the fragments follow the isoscaling law, and a strong linear correlation is observed between the isoscaling parameter $\alpha$ and the source asymmetry difference $\mathrm{\Delta }\left[{(Z_s/A_s)}^2\right]$ across different systems and fragment groups, supporting statistical equilibrium during fragment formation. Based on this correlation, $C_{\mathrm{sym}}$ is extracted for fragments with charge numbers $Z=4–26$ at specified temperatures. The results indicate a pronounced sensitivity of $C_{\mathrm{sym}}$ to fragment selection, temperature, and reaction system, while also revealing the method's limitations with heavier targets such as Xe. This BNN-based isoscaling methodology offers a viable pathway to constrain the nuclear symmetry energy. Its integration with future high-precision experiments and canonical ensemble treatments will further refine constrains on the nuclear equation of state.

We present a study of the single- and multistrange particle productions in $p\mathrm{Pb}$ collisions at $\sqrt{s_{NN}}=5.02$ TeV using the PACIAE 4.0 model. The effects of color reconnection (CR), rope hadronization (RH), as well as partonic and hadronic rescatterings (PRS and HRS) on their productions are investigated. There are two kinds of CR considered: the multiparton-interactions-based CR (MPI-CR) and the quantum-chromodynamics-based CR (QCD-CR). The four mechanisms studied have little effect on kaon production. The QCD-CR scheme incorporating the junction topology gives an enhanced baryon production, but it is still not enough to describe the data of integrated yields of strange baryons. The combination of QCD-CR and the RH scheme together with flavor ropes (FR) and string shoving (SS) provides a good description for the data of strange baryon production. For the heavier $\mathrm{\Xi }$ and $\mathrm{\Omega }$ baryons, an improved $\mathrm{QCD}\text{−}\mathrm{CR}+\mathrm{FR}$ scheme with stronger tension is required, whereas the $\mathrm{QCD}\text{−}\mathrm{CR}+\mathrm{FR}+\mathrm{SS}$ scheme adequately describes $\mathrm{\Lambda }$ production. PRS has a weak effect, but HRS exerts a promoting effect on the production of multistrange baryons ($\mathrm{\Xi }$ and $\mathrm{\Omega }$).

Based on the microscopic mechanism of the particle-hole (p-h) excitations in the proton and neutron single-particle energy levels relative to the Fermi energy, a search for islands of shape coexistence (SC) is performed over a wide range of even-even nuclei from $Z=38$ to 84 using nonrelativistic self-consistent mean field with the Hartree-Fock-Bogoliubov theory using the Skyrme-SKI3 functional. The results of the present study show that neutron-induced islands of SC, corresponding to proton p-h excitations, are found around the magic numbers $Z=82$ and 50, centered at the relevant neutron midshells of $N=104$ and 66 respectively, while proton-induced islands of SC, corresponding to neutron p-h excitations, are found around the neutron numbers $N=90$ and 60, centered at the relevant proton midshells $Z=66$ and 38 respectively. In addition, islands of SC due to both neutron and proton particle-hole excitations are found around $N=40, Z=40$. The results of the present study are compared with the results of covariant density functional theory using the DDME2 functional, using the same p-h mechanism. The islands of SC that appeared in the covariant density functional theory work with the DDME2 functional are corroborated by the present study with the Skyrme-SKI3 functional, thus confirming the robustness of the particle-hole excitations mechanism in searching for islands of SC. In addition, the current study reveals new regions of SC, adjacent to the earlier islands and expanding their shores.

A comprehensive assessment of theoretical uncertainties defines an important frontier in nuclear structure research. Ideally, theory predictions include uncertainty estimates that take into account truncation effects from both the interactions and the many-body expansion. While the uncertainties from the expansion of the interactions within effective field theories have been studied systematically using Bayesian methods, many-body truncations are usually addressed by expert assessment. In this work we use a Bayesian framework to study many-body uncertainties within many-body perturbation theory applied to finite nuclei. Our framework is applied to a broad range of nuclei across the nuclear chart calculated from two- and three-nucleon interactions based on chiral effective field theory. These developments represent a step towards a more complete and systematic quantification of uncertainties in ab initio calculations of nuclei.

A multitask Gaussian process (GP) machine learning model is introduced to simultaneously predict two important nuclear observables across the nuclear chart, namely nuclear masses and charge radii. Utilizing 12 physical input features, our multitask GP consistently outperforms single-task learning. We obtain overall root-mean-square deviations of 0.136 MeV for masses and 0.007 fm for charge radii, respectively. The good performance of the present model is confirmed by three complementary validations in the present work. More explicitly, we employ the fractions of training and testing data, extrapolations to newly reported nuclei far from stability, and comparisons with the popular Garvey-Kelson mass relations. The correlations between the two observables are explicitly analyzed within the multi-task learning framework. Furthermore, by employing the SHapley Additive exPlanations (SHAP) method, we interpret the importance of different features for mass and radius predictions across distinct nuclear regions. These results demonstrate the effectiveness of the multitask GP approach for high-accuracy nuclear property predictions.

A recent ${}^{47}\mathrm{K}(d,p\gamma ){}^{48}\mathrm{K}$ transfer reaction measurement identified new excited states in ${}^{48}\mathrm{K}$ and extracted the corresponding spectroscopic factors (SFs) [C. J. Paxman et al., Phys. Rev. Lett. 134, 162504 (2025)], but exposed sizable discrepancies with large-scale shell-model (LSSM) calculations—especially for the low-lying states—suggesting shortcomings in the proton-neutron interaction employed by the LSSM. In this work, we revisit the low-lying states and SFs of ${}^{48}\mathrm{K}$ using the ab initio valence-space in-medium similarity renormalization group (VS-IMSRG) approach based on the chiral two- and three-nucleon forces. The calculated excitation energies reproduce the experimental data for ${}^{48}\mathrm{K}$, whereas computed SFs systematically exceed experimental values. We trace this overestimation to missing reduction factors that account for nonidealities of the transfer reaction. After introducing a phenomenological reduction factor, our VS-IMSRG results and the LSSM calculations achieve agreement with experiment. We also perform the same analysis for the neutron SFs of ${}^{47}\mathrm{Ar}$. Furthermore, we extend the ab initio calculations across the $N=28$ isotones, computing excitation energies and single-neutron transfer SFs from $N=29$ isotones ranging from ${}^{48}\mathrm{K}$ to ${}^{45}\mathrm{S}$. By systematically removing protons from ${}^{48}\mathrm{K}$ to ${}^{45}\mathrm{S}$, we trace the evolution of the $N=28$ shell strength via theoretical SFs values. Our results provide a microscopic pathway to quantify the weakening of the $N=28$ shell closure.

We report the first measurement of ${}^{115}\mathrm{Sn}(p,\gamma ){}^{116}\mathrm{Sb}$ cross sections using the activation technique in the beam energy range of 2.5–6.0 MeV, covering nearly the entire Gamow window relevant to the $p$-process nucleosynthesis of ${}^{115}\mathrm{Sn}$. Cross sections for both the ground and metastable states of ${}^{116}\mathrm{Sb}$ were determined, and the corresponding astrophysical S factors were extracted. After correcting for electron screening effects, the screened cross sections and S factors were compared with Hauser-Feshbach statistical model predictions. talys calculations with default input parameters reproduce the screened data reasonably well, while non-smoker predictions show significant deviations. Stellar reaction rates were calculated using the default talys inputs and compared with rates from the JINA REACLIB database for both the forward ${}^{115}\mathrm{Sn}(p,\gamma ){}^{116}\mathrm{Sb}$ and the inverse ${}^{116}\mathrm{Sb}(\gamma ,p){}^{115}\mathrm{Sn}$ reactions. These rates will provide valuable constraints toward resolving the long-standing debate on the $p$-process contribution to the solar abundance of ${}^{115}\mathrm{Sn}$.

Background: Observed systematic deviations of the value of the $B(E1;1_1^{-}\to 0_1^{+})/B(E1;3_1^{-}\to 2_1^{+})$ ratio in spherical nuclei from the prediction of the collective model which take into account only quadrupole and octupole collective modes are considered.

Purpose: Our purpose is to evaluate the effect of the isovector dipole and quadrupole-octupole modes coupling on the $B(E1;1_1^{-}\to 0_1^{+})/B(E1;3_1^{-}\to 2_1^{+})$ ratio.

Methods: The Hamiltonian of the phenomenological collective model is used to calculate mixing of the isovector dipole and quadrupole and octupole modes.

Results: The effect of the admixture of the giant dipole resonance to the low-lying collective quadrupole and octupole modes is estimated. The ratio $B(E1;1_1^{-}\to 0_1^{+})/B(E1;3_1^{-}\to 2_1^{+})$ for different nuclei is calculated.

Conclusion: It is shown that the coupling of the quadrupole and octupole collective modes to giant dipole resonance leads to a decrease of the ratio $B(E1;1_1^{-}\to 0_1^{+})/B(E1;3_1^{-}\to 2_1^{+})$ relative to the value 7/3 predicted by the pure collective quadrupole-octupole model.

Using the Hydro-Coal-Frag model that combines hydrodynamics at low $p_{\mathrm{T}}$, quark coalescence at intermediate $p_{\mathrm{T}}$, and the LBT transport model at high $p_{\mathrm{T}}$, we study the spectra and elliptic flow of identified hadrons in high multiplicity $p$–Pb and $p$–$p$ collisions at the CERN Large Hadron Collider (LHC). In $p$–Pb collisions, the Hydro-Coal-Frag model gives a good description of the differential elliptic flow over the $p_{\mathrm{T}}$ range from 0 to 6 GeV and the approximate number of constituent quark (NCQ) scaling at intermediate $p_{\mathrm{T}}$. Although the Hydro-Coal-Frag model can also roughly describe the elliptic flow in high multiplicity $p$–$p$ collisions with the quark coalescence process, the larger contribution from the string fragmentations leads to a notable violation of the NCQ scaling of $v_2$ at intermediate $p_{\mathrm{T}}$ as observed in the experiment. Comparison runs of the Hydro-Frag model without the coalescence process demonstrate that regardless the parameter adjustments, the Hydro-Frag model cannot simultaneously describe the $p_{\mathrm{T}}$ spectra and the elliptic flow of identified hadrons in either $p$–Pb collisions or $p$–$p$ collisions. The calculations in this paper thus provide support for the existence of partonic degrees of freedom and the possible formation of the QGP in the small systems created at the LHC.