Heavy-ion collisions provide a unique opportunity for studying the properties of exotic hadrons with two charm quarks. The production of $T_{cc}^{+}$ is significantly enhanced in nuclear collisions compared to proton-proton collisions due to the creation of multiple-charm pairs. In this study, we employ the Langevin equation in combination with the instantaneous coalescence model (LICM) to investigate the production of $T_{cc}^{+}$ and ${\mathrm{\Xi }}_{cc}^{++}$ which consists of two charm quarks. We consider $T_{cc}^{+}$ as molecular states composed of $D$ and $D^{*}$ mesons. The Langevin equation is used to calculate the energy loss of charm quarks and $D$ mesons in the hot medium. The hadronization process, where charm quarks transform into each $D$ state as constituents of $T_{cc}^{+}$ production, is described using the coalescence model. The coalescence probability between $D$ and $D^{*}$ is determined by the Wigner function, which encodes the information of the $T_{cc}^{+}$ wave function. Our results show that the $T_{cc}^{+}$ production varies by approximately 1 order of magnitude when different widths in the Wigner function, representing distinct binding energies of $T_{cc}^{+}$, are considered. This variation offers valuable insights into the nature of $T_{cc}^{+}$ through the analysis of its wave function. ${\mathrm{\Xi }}_{cc}^{++}$ is treated as a hadronic state produced at the hadronization of the deconfined matter. Its production is also calculated as a comparison with the molecular state $T_{cc}^{+}$.

The quadrupole transition strength $B\left(E2\right)$ deduced from the measured level lifetimes using the Doppler shift attenuation method with the help of the Indian National Gamma Array, decreases with increasing spin for the band of interest in ${}^{82}\mathrm{Kr}$. In addition, the ratio of the dynamic moment of inertia with the $B\left(E2\right)$ value increases along the band. Large basis shell-model calculations have been performed to understand the microscopic origin of the band of interest. The experimental results are reproduced well by the numerical calculations within the framework of a semiclassical geometric model, which conclusively establish the antimagnetic rotation in the shape-phase transition point nucleus ${}^{82}\mathrm{Kr}$ in the $A\approx 80$ mass region. Present investigation represents the first conclusive evidence of an antimagnetic rotational band based on the valence protons and neutrons in the $1g_{9/2}$ orbitals in an atomic nucleus.

The $\beta$-decaying states of ${}^{70,72}\mathrm{Co}$ were studied at the National Superconducting Cyclotron Laboratory using the VANDLE neutron time-of-flight array. The $(6^{-},7^{-})\beta$-decaying state in ${}^{70}\mathrm{Co}$ is near-spherical with a lifetime of $113\pm 7$ ms, and the low-spin $(1^{+},2^{+})\beta$-decaying state is postulated to be the prolate deformed ground state with a lifetime of $508\pm 7$ ms. Both decay predominantly to the bound states of ${}^{70}\mathrm{Ni}$. For the first time neutron-emissions from neutron unbound states from both the $(6^{-},7^{-})$ and $(1^{+},2^{+})\beta$ decays were measured. Even with the low statistics data, we were able to disentangle the neutron emission from both decays, which enabled a determination of $\beta$-decay strength above the neutron separation energy of ${}^{70}\mathrm{Ni}$. Neutron emission probabilities were measured to be $7.1\pm 1.5\%$ and $9.4\pm 1.7\%$, respectively, for the $(6^{-},7^{-})$ and $(1^{+},2^{+})$ decays. The decay pattern of the ${}^{70}\mathrm{Co}$ is driven by neutron $f_{5/2}$ to proton $f_{7/2}$ Gamow-Teller transformation. The observed population of neutron unbound states is attributed to the conversion of $p_{1/2}$ and $p_{3/2}$ neutrons to $p_{3/2}$ and $p_{1/2}$ protons excited across the $Z=28$ closed shell.

Background: Nowadays, modern microscopic approaches for fission are generally based on the framework of nuclear density functional theory (DFT), which has enabled a self-consistent treatment of both static and dynamic aspects of fission. The key issue is a DFT solver with high precision and efficiency especially for the large elongated configurations.

Purpose: We aim to develop a DFT solver with high precision and efficiency based on the point coupling covariant density functional theory (CDFT), which has achieved great success in describing properties of nuclei for the whole nuclear chart.

Method: We have extended the point-coupling CDFT to be based on the two-center harmonic oscillator (TCHO) basis, which matches well with the large elongated configurations during the fission process. A multidimensional constraint and the time-dependent generator coordinate method (TDGCM) have been used to analyze the fission potential energy surface (PES) and fission dynamics, respectively. To simulate the splitting process of the nascent fragments beyond scission, we also introduce a density constraint into the new CDFT framework.

Results: Illustrative calculations have been done for the PESs and induced fission dynamics of two typical examples: ${}^{226}\mathrm{Th}$ and ${}^{240}\mathrm{Pu}$. A more reasonable PES is obtained in the new framework compared to that based on the one-center harmonic oscillator (OCHO) with the same basis space. An optimization of about $0.2–0.3$ MeV has been achieved for the outer fission barriers and large elongated configurations. The dynamical simulations based on CDFT-TCHO show an improved description of fission yields.

Conclusions: The newly developed CDFT solver optimizes the elongated configurations, improves the calculation efficiency, and provides a basis for large-scale multidimensional constraint calculations and dynamical simulations.

An investigation using the ${}^{27}\mathrm{Al}({}^{28}\mathrm{Si}, 3p1n)$ reaction and the high-efficiency Indian National Gamma Array has yielded an enriched level scheme for the ${}^{51}\mathrm{Cr}$ nucleus. Multiple new $\gamma$ rays, including high-energy feeders to the yrast states, have been observed. The yrast $K^{\pi }={\frac{15}{2}}^{-}$ three-quasiparticle band structure has been extended beyond band termination. Angular correlation and polarization measurements have yielded unambiguous spins and parities to most of the observed yrast states. Unambiguous measurements of mean lifetimes for the yrast states in the $K^{\pi }={\frac{15}{2}}^{-}$ band, leading to and even beyond band termination, have been carried out for the first time in this nucleus. This, coupled with the clear identifications of weak intraband crossover transitions, have facilitated profiling of the evolution of $B\left(E2\right)$ values along the yrast sequence. Large-scale shell model calculations in the full $fp$ valence space, with no restriction on the occupancy of the valence orbitals, have been performed. The results from such calculations have been found to be consistent with the experimental observations.

Through ensemble learning with multitasking and complex connection neural networks, we aggregated nuclear properties, including ground-state density distributions, charge radii, and binding energies obtained from the Kohn-Sham auxiliary single-particle systems. The root-mean-squared (RMS) error in describing binding energies is reduced to about 500 keV, while the RMS error in describing charge radii is decreased to about 0.017 fm. In addition, by using the correlation between densities and binding energies, we discuss the impact of various densities and nuclear radii on the binding energy and find the neutron-skin thickness of ${}^{208}\mathrm{Pb}$ to be around $0.220\mathrm{fm}$. The present paper provides a new way to accelerate the integration of machine learning into nuclear density functional theory.

Based on a momentum-space in-medium folding model, we disclose the universal separability of the optical potential, revealing its radial and nonlocality features at beam energies in the range 40–400 MeV and target mass numbers in the range $40\le A\le 208$. From this microscopic study we find that the nonlocality form factor is inherently complex and of hydrogenic nature, affecting both central and spin-orbit components of the potential. A striking outcome from this study is the consistent appearance of a nodal point in the imaginary radial form factor, notably suppressing surface absorption peaks, in evident contrast with Woods-Saxon's assumption of an absorptive peak at the nuclear surface. Our analysis reveals that the complex radial form factor can effectively be represented as convolutions of uniform spherical distribution with a Gaussian form factor and a Yukawa term. These robust microscopically driven findings offer new ways for investigating nuclear reactions beyond the restricting Woods-Saxon and Perey-Buck assumptions.

We investigate the effect of the quantum chromodynamics (QCD) critical point on the isentropic trajectories in the QCD phase diagram. We point out that the universality of the critical equation of state and the third law of thermodynamics require the specific entropy (per baryon) along the coexistence (first-order transition) line to be nonmonotonic at least on one side of that line. Specifically, a maximum must occur. We show how the location of the maximum relative to the QCD critical point depends on the parameters of the critical equation of state commonly used in the literature. We then examine how the isentropic trajectories followed by adiabatically expanding heavy-ion collision fireballs behave near the critical point. We find that a crucial role is played by the sign of the isochoric temperature derivative of pressure at the critical point; this sign determines on which side of the coexistence curve the specific entropy must be nonmonotonic (i.e., has a maximum). We classify different scenarios of the adiabatic expansion that arise depending on the value of the discriminant parameter and the proximity of the trajectory to the critical point.

Muon capture on nuclei is one of the most promising probes of the nuclear electroweak current driving the yet-hypothetical neutrinoless double-beta ($0\nu \beta \beta$) decay. Both processes involve vector and axial-vector currents at finite momentum transfer, $q\approx 100$ MeV, as well as the induced pseudoscalar and weak-magnetism currents. Comparing measured muon-capture rates with reliable ab initio nuclear-theory predictions could help us validate these currents. To this end, we compute partial muon-capture rates for ${}^6\mathrm{Li}$, ${}^{12}\mathrm{C}$, and ${}^{16}\mathrm{O}$, feeding the ground and excited states in ${}^6\mathrm{He}$, ${}^{12}\mathrm{B}$, and ${}^{16}\mathrm{N}$, using ab initio no-core shell model with two- and three-nucleon chiral interactions. We remove the spurious center-of-mass motion by introducing translationally invariant operators and approximate the effect of hadronic two-body currents by Fermi-gas model. We solve the bound-muon wave function from the Dirac wave equations in the Coulomb field created by a finite nucleus. We find that the computed rates to the low-lying states in the final nuclei are in good agreement with the measured counterparts. We highlight sensitivity of some of the transitions to the sub-leading three-nucleon interaction terms. We also compare summed rates to several tens of final states with the measured total capture rates and note that we slightly underestimate the total rate with this simple approach due to limited range of excitation energies.

Experimental data on proton-induced neutron emission reactions in actinides are important for nuclear astrophysics, nuclear energy, and medical applications. Presently existing data on $(p,xn)$ reactions in thorium and uranium at low energies range $(E_{\mathrm{p}}<20\mathrm{MeV})$ are somеwhat scarce and often contradict each other. In this work, the cross sections of proton-induced ${}^{232}\mathrm{Th}(p,n){}^{232}\mathrm{Pa}$, ${}^{232}\mathrm{Th}(p,3n){}^{230}\mathrm{Pa}$, ${}^{238}\mathrm{U}(p,n){}^{238}\mathrm{Np}$, ${}^{238}\mathrm{U}(p,3n){}^{236\mathrm{m}}\mathrm{Np}$, and ${}^{238}\mathrm{U}(p,np){}^{237}\mathrm{U}$ reactions are measured at the proton energy range 12–17 MeV using the stacked-foil technique and with the induced activation method. γ-ray spectroscopy is used to identify the resulting radionuclides and to determine their yields. In total, there are 21 cross sections determined in this work for the listed reactions. This new data set can help to clear up the discrepancies between existing data sets from different experiments, as well as to fill in the gap of missing low-energy data. The cross-section data are compared to the predictions of the nuclear reactions simulation code TALYS1.96, using different combinations of options of several main ingredients of the code, such as the photon strength function, the optical model potential, the fission barrier, the nuclear level density, and the pre-equilibrium mechanism.

We observed a new isomeric $\gamma$ transition at 168 keV in ${}^{36}\mathrm{Mg}$, with a half-life of $T_{1/2}=90{(}_{-50}^{+410})$ ns. We propose that the observed transition deexcites a new $0^{+}$ isomeric state at 833 keV and populates the previously known first $2^{+}$ state. The existence of this isomer is consistent with the predictions of the large-scale shell-model calculations of ${}^{36}\mathrm{Mg}$ using the sdpf-u-mix interaction. The observed excitation energy of the second $0^{+}$ state is caused by the small energy separation between two prolate-deformed configurations where the intruder configuration corresponds to two-neutron excitations from the sd to the pf shell. Within this interpretation, ${}^{36}\mathrm{Mg}$ becomes the crossing point between nuclei in which ground state deformed/superdeformed configurations are caused by the dominance of $N=20$ intruders $\left({}^{32,34}\mathrm{Mg}\right)$ and nuclei where deformed configurations are associated with the breaking of the $N=28$ closure and a large occupancy of the $1p_{3/2}$ neutron orbit (${}^{38}\mathrm{Mg}$ and beyond). We found the lack of three-body monopole corrections in other effective interactions results in a predominance of $N=20$ intruder configurations past ${}^{38}\mathrm{Mg}$ incompatible with our observation. We conclude that ${}^{36}\mathrm{Mg}$ bridges the $N=20$ and $N=28$ islands of inversion, forming the so-called big island of deformation.

The large reported $E2$ strength between the $2^{+}$ ground state and $1^{+}$ first excited state of ${}^8\mathrm{Li}, B(E2;2^{+}\to 1^{+})=55\left(15\right)e^2{\mathrm{fm}}^4$, presents a puzzle. Unlike in neighboring $A=7–9$ isotopes, where enhanced $E2$ strengths may be understood to arise from deformation as rotational in-band transitions, the $2^{+}\to 1^{+}$ transition in ${}^8\mathrm{Li}$ cannot be understood in any simple way as a rotational in-band transition. Moreover, the reported strength exceeds ab initio predictions by an order of magnitude. In light of this discrepancy, we revisited the Coulomb excitation measurement of this strength, now using particle-$\gamma$ coincidences, yielding a revised $B(E2;2^{+}\to 1^{+})$ of $19{(}_{-6}^{+7})\left(2\right)e^2{\mathrm{fm}}^4$. We explore how this value compares to what might be expected in the limits of rotational models. While the present value is about a factor of three smaller than previously reported, the current experimental data indicates that the $B\left(E2\right)$ value remains anomalously enhanced.

Developing methods to solve nuclear many-body problems with quantum computers is an imperative pursuit within the nuclear physics community. Here, we introduce a quantum algorithm to accurately and precisely compute the ground state of valence two-neutron systems leveraging presently available noisy intermediate-scale quantum devices. Our focus lies on the nuclei having a doubly magic core plus two valence neutrons in the $p, sd$, and $pf$ shells, i.e., ${}^6\mathrm{He}, {}^{18}\mathrm{O}$, and ${}^{42}\mathrm{Ca}$, respectively. Our ansatz, quantum circuit, is constructed in the pair-wise form, taking into account the symmetries of the system in an explicit manner, and enables us to reduce the number of qubits and the number of CNOT gates required. The results on a real quantum hardware by IBM Quantum Platform show that the proposed method gives very accurate results of the ground-state energies, which are typically within $0.1\%$ error in the energy for ${}^6\mathrm{He}$ and ${}^{18}\mathrm{O}$ and at most $1\%$ error for ${}^{42}\mathrm{Ca}$. Furthermore, our experiments using real quantum devices also show the pivotal role of the circuit layout design, attuned to the connectivity of the qubits, in mitigating errors.

In this paper we study the valence mirror symmetry between the Sn ($Z=50$) isotopes and $N=82$ isotones, in the frameworks of the nuclear shell model (NSM) and its nucleon-pair approximation (NPA). The NPA energy spectra and electromagnetic properties for yrast states are well consistent with the shell-model results as well as available data in experiments. Remarkable correspondences of the energy spectra and electromagnetic matrix elements between the even-even Sn isotopes and $N=82$ isotones are emphasized in both the experimental data and theoretical calculations. The asymmetry of $E_{2_1^{+}}$ values are explained in terms of the evolution of single-particle energy splitting between the $1g_{7/2}$ and $2d_{5/2}$ orbits for the $N=82$ isotones.

Background: Multinucleon transfer (MNT) processes in low-energy deep inelastic (damped) collisions of heavy ions can be employed to produce heavy neutron-enriched nuclei. Recent progress in development of radioactive-ion beam (RIB) facilities may give additional possibilities in producing nuclei with large neutron excess.

Purpose: A major aim of the work is to calculate the cross sections of heavy neutron-rich isotopes with the magic number $N=126$ in the reactions ${}^{132}\mathrm{Sn}+{}^{198}\mathrm{Pt}$ and ${}^{136,138,140}\mathrm{Xe}+{}^{198}\mathrm{Pt}$ within a multidimensional dynamical model based on the Langevin equations. Another purpose of the paper is to study the relative production rates of such nuclei reachable at currently working RIB facilities.

Method: A multidimensional dynamical model of nucleus-nucleus collisions based on the Langevin equations [A. V. Karpov and V. V. Saiko, Phys. Rev. C 96, 024618 (2017)] has been used in the present work. This model provides a reasonable description of available experimental data.

Results: Cross sections of heavy neutron-enriched nuclides obtained in the MNT reactions ${}^{132}\mathrm{Sn}+{}^{198}\mathrm{Pt}$ and ${}^{136,138,140}\mathrm{Xe}+{}^{198}\mathrm{Pt}$ have been calculated. Relative production rates of these nuclei were estimated using beam intensities available at currently working RIB facilities.

Conclusions: Using neutron-rich radioactive projectiles in multinucleon transfer reactions with the ${}^{198}\mathrm{Pt}$ target, one can reach an order of magnitude higher cross sections of neutron-enriched nuclides with the magic number $N=126$. Relative production yields of such nuclei increase with the increasing $N/Z$ ratio of the projectile.

The mass distributions of fragment for neutron-induced ${}^{235,238}\mathrm{U}, {}^{237}\mathrm{Np}$, and ${}^{239}\mathrm{Pu}$ fission were studied using the improved scission point model by considering the octupole deformation of the fragments over a wide range of incident neutron energies ($E_n=10-50\mathrm{MeV}$). The multichance fission mechanism ensures that the mass distributions remain highly asymmetric even at high energy. We also investigated the role of octupole deformation of fragments in the multichance fission mechanism. The results obtained using the improved scission point model accurately replicated the experimental data. This model is expected to further our understanding of the fission process of actinides in the high excitation energy region.

We study parton energy-momentum exchange with the quark gluon plasma (QGP) within a multistage approach composed of in-medium Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution at high virtuality, and (linearized) Boltzmann transport formalism at lower virtuality. This multistage simulation is then calibrated in comparison with high-$p_T$ charged hadrons, $D$ mesons, and the inclusive jet nuclear modification factors, using Bayesian model-to-data comparison, to extract the virtuality-dependent transverse momentum broadening transport coefficient $\widehat{q}$. To facilitate this undertaking, we develop a quantitative metric for validating the Bayesian workflow, which is used to analyze the sensitivity of various model parameters to individual observables. The usefulness of this new metric in improving Bayesian model emulation is shown to be highly beneficial for future such analyses.

In this work, we present new extractions of the proton $\langle r_p\rangle$ and neutron $\langle r_n^2\rangle$ root-mean-square charge radius using the Dirac flavor-separated up- and down-quark $F_1^{(u,d)}\left(Q^2\right)$ form factors data covering the range $0.0155<Q^2<4.250 {\mathrm{GeV}}^2$ from I. A. Qattan and J. Arrington [Phys. Rev. C 86, 065210 (2012)] and I. A. Qattan, J. Arrington, and A. Alsaad [Phys. Rev. C 91, 065203 (2015)]. The charge radius values are calculated using the two-dimensional (2D) transverse quark charge distributions based on the slopes of $F_1^{(u,d)}\left(Q^2\right)$ at $Q^2=0$ through model-independent relations. As the charge radius is extracted in the limit $Q^2\to 0$ with focus mainly on low-$Q^2$ data points, we limit our extraction up to $Q^2=1.0{\mathrm{GeV}}^2$, and investigate the impact of fitting procedure, data fitting range, and convergence of the fitted functions used on the stability and precision of the extracted charge radius. In addition, we investigate any model dependence of the fits that might be associated with the inclusion of high-$Q^2$ data points by extending the fitting range up to $Q^2=4.25 {\mathrm{GeV}}^2$. For the proton, we find $\langle r_p\rangle =0.848\pm 0.002\text{(stat.)}\pm 0.003\text{(sys.)}$ fm, which is in excellent agreement with the ultra-high precise muonic hydrogen $\mu \mathrm{H}$ Lamb shift results and PRad I Collaboration measurements, but in disagreement with the Mainz Collaboration extractions and the Particle Data Book (CODATA 2010–2014) results. For the neutron, we find $\langle r_n^2\rangle =-0.089\pm 0.002\text{(stat.)}\pm 0.002\text{(sys.)} {\mathrm{fm}}^2$, which is $\approx 23.6$% below the value obtained by the recent precise measurements of the neutron $G_E^n\left(Q^2\right)$ form factor at low-$Q^2$ utilizing the connection between the $N\to \mathrm{\Delta }$ quadrupole transitions and $G_E^n\left(Q^2\right)$, and $\approx 29.4$% below the new adjusted $\langle r_n^2\rangle$ world data value.

This article presents an investigation of isospin equilibration in cross-bombarding ${}^{40,48}\mathrm{Ca}+{}^{40,48}\mathrm{Ca}$ reactions at 35 MeV/nucleon, by comparing experimental data with filtered transport model calculations. Isospin diffusion is studied using the evolution of the isospin transport ratio with centrality. The asymmetry parameter $\delta =(N-Z)/A$ of the quasiprojectile (QP) residue is used as isospin-sensitive observable, while a recent method for impact parameter reconstruction is used for centrality sorting. A benchmark of global observables is proposed to assess the relevance of the antisymmetrized molecular dynamics (amd) model, coupled to gemini$++$, in the study of dissipative collisions. Our results demonstrate the importance of considering cluster formation to reproduce observables used for isospin transport and centrality studies. Within the amd model, we prove the applicability of the impact parameter reconstruction method, enabling a direct comparison to the experimental data for the investigation of isospin diffusion. For both, we evidence a tendency to isospin equilibration with an impact parameter decreasing from 9 to 3 fm, while the full equilibration is not reached. A weak sensitivity to the stiffness of the equation of state employed in the model is also observed, with a better reproduction of the experimental trend for the neutron-rich reactions.

Extensive elastic scattering data measured at energies around 10 to 20 MeV/nucleon for some light identical systems, like ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$, were shown to exhibit the nuclear rainbow pattern of broad Airy oscillations of the elastic scattering cross section at medium and large angles. Because of the identity of the scattered projectile and recoiled target, the smooth rainbow pattern at angles around and beyond ${\theta }_{\mathrm{c}.\mathrm{m}.}\approx {90}^{\circ }$ is strongly deteriorated by the boson exchange in the ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ systems at low energies. The exchange symmetry of two identical nuclei implies the Mott interference of the direct and exchange scattering amplitudes, which destroys the nuclear rainbow pattern. The nuclear rainbow features in the elastic scattering of two identical nuclei have been discussed so far based on the nearside-farside (NF) decomposition of the scattering amplitude given by an optical model calculation neglecting the projectile-target exchange symmetry. Moreover, the NF decomposition method was developed in the 1970s by Fuller for nonidentical dinuclear systems only, and the details of how the exchange symmetry of an identical system affects the evolution of nuclear rainbow remain unexplored. For this purpose, the Fuller method is generalized in the present work for the elastic scattering of two identical (spin-zero) nuclei, with the projectile-target exchange symmetry taken explicitly into account. The results obtained for elastic ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$ scattering at low energies show that the exchange symmetry results in a symmetric interchange of the nearside and farside scattering patterns at angles passing through ${\theta }_{\mathrm{c}.\mathrm{m}.}={90}^{\circ }$, which requires a more subtle interpretation of nuclear rainbow. We found further that a similar NF interchange also occurs in a nonidentical nucleus-nucleus system with the core-core symmetry at low energies, where the elastic cross section at backward angles is due mainly to the elastic transfer of cluster or nucleon between two identical cores. This interesting effect is illustrated in the elastic ${}^{16}\mathrm{O}+{}^{12}\mathrm{C}$ scattering at low energies where the elastic $\alpha$ transfer between two ${}^{12}\mathrm{C}$ cores has been proven to enhance the elastic cross section at backward angles.