We employ the constrained density functional theory to investigate cluster phenomena for the ${}^{12}\mathrm{C}$ nucleus. The proton and neutron densities are generated from the placement of three ${}^4\mathrm{He}$ nuclei ($\alpha$ particles) geometrically. These densities are then used in a density constrained Hartree-Fock calculation that produces an antisymmetrized state with the same densities through energy minimization. In the calculations no a priori analytic form for the single-particle states is assumed and the full energy density functional is utilized. The geometrical scan of the energy landscape provides the ground state of ${}^{12}\mathrm{C}$ as an equilateral triangular configuration of three $\alpha \mathrm{s}$ with molecular bond like structures. The use of the nucleon localization function provides further insight to these configurations. One can conclude that these configurations are a hybrid between a pure mean-field and a pure $\alpha$ particle condensate. This development could facilitate density functional theory based fusion calculations with a more realistic ${}^{12}\mathrm{C}$ ground state.

We investigate the in-medium masses of the pseudoscalar $(D,\overline{D},D_s^{\pm })$, and vector $(D^{*},{\overline{D}}^{*},D_s^{*\pm })$, open charm mesons in isospin asymmetric magnetized nuclear matter, accounting for the effects of the Dirac sea. The masses are used to study the in-medium partial decay widths of $D^{*}\to D\pi$ (${\overline{D}}^{*}\to \overline{D}\pi$) and $\mathrm{\Psi }\left(3770\right)\to D\overline{D}$, using the ${}^{3}P_0$ model. The in-medium masses of the open charm mesons are calculated from their interactions with the nucleons and scalar mesons within the generalized chiral effective model in terms of the scalar and number densities of nucleons and the scalar fields fluctuations. The free energy of the magnetized vacuum with Landau energy levels and anomalous magnetic moments (AMMs) of the charged fermions in the single fermion energies are taken into account in the Dirac sea contribution. The effects of Landau energy levels of protons and AMMs of the nucleons are also considered in the magnetized nuclear matter. The light quark condensates are modified considerably with magnetic field, leading to (inverse) magnetic catalysis due to the magnetized Dirac sea effects. The magnetic field causes modifications to occur due to the mixing of the pseudoscalar and longitudinal component of the vector mesons, along with the lowest Landau-level contribution to the ground-state energy of the charged mesons as point-particle correction. For the charmonium state $\mathrm{\Psi }\left(3770\right)$, the effects of the magnetized Dirac sea are incorporated to the mass modifications through the medium-modified scalar dilaton field $\chi$ within the chiral model. The in-medium masses and decay widths of the open charm and charmonium mesons thus obtained should have important observable consequences in the production of the open charm mesons and charmonia in noncentral ultrarelativistic heavy-ion collision experiments, where huge magnetic fields are expected to be created.

The ${}^{12}\mathrm{C}(p,\gamma ){}^{13}\mathrm{N}$ reaction is the onset process of both the CNO and hot CNO cycles that drive massive star, red and asymptotic giant branch star, and novae nucleosynthesis. The ${}^{12}\mathrm{C}(p,\gamma ){}^{13}\mathrm{N}$ rate affects the final abundances of the stable ${}^{12,13}\mathrm{C}$ nuclides with ramifications for meteoritic carbon isotopic abundances and the $s$-process neutron source strength. Here, an underground measurement of the ${}^{12}\mathrm{C}(p,\gamma ){}^{13}\mathrm{N}$ cross section is reported. The present data, obtained at the Felsenkeller shallow-underground laboratory in Dresden (Germany), encompass the 320–620 keV center of mass energy range to include the wide and poorly constrained $E=422$ keV resonance that dominates the rate at high temperatures. This work's $S$-factor results, lower than literature by 25%, are included in a comprehensive $R$-matrix fit, and the energy of the ${\frac{1}{2}}^{+}$ first excited state of ${}^{13}\mathrm{N}$ is found to be 2369.6(4) keV with a radiative and proton width of 0.49(3) eV and 34.9(2) keV, respectively. A reaction rate, based on the present $R$-matrix fit and extrapolation, is suggested.

The Hamiltonian including core excitations and the intruder orbit $i_{13/2}$ is used to investigate spectroscopic factors and level spectra in neutron-rich Sn isotopes. The state $13/2^{+}$ of ${}^{131}\mathrm{Sn}$ is predicted with a relative small value of spectroscopic factor, since the competition driven by pair cross-shell excitations weakens the single particle properties of this high-lying state near 5 MeV. The level $11/2^{-}$ of ${}^{133}\mathrm{Sn}$ is predicted at 3.6 MeV coupled by cross-shell configuration $\nu h_{11/2}^{-1}{f}_{7/2}^2$. In ${}^{135}\mathrm{Sn}$,the state $3/2^{+}$ is predicted at 2.66 MeV with a main cross-shell configuration $\nu d_{3/2}^{-1}{f}_{7/2}^4$, and the state $13/2^{+}$ at about 2.5 MeV is predicted as a good isomer coupled by intruder orbit $i_{13/2}$. The level $3^{-}$ of ${}^{134}\mathrm{Sn}({}^{136}\mathrm{Sn}$) is predicted as a good isomer, due to the $\gamma$ decay blocked by the spin-trap structures. The level $13/2^{+}$ of ${}^{137}\mathrm{Sn}$ is predicted at about 2.1 MeV with $49\%$ of configuration $\nu f_{7/2}^4{i}_{13/2}$. The ground state of ${}^{137}\mathrm{Sn}$ is predicted as $7/2^{-}$ level with a main configuration $\nu f_{7/2}^5$. This work emphasizes the importance of the intruder orbit $i_{13/2}$ to explain level spectra of neutron-rich Sn isotopes, and these predictions would provide useful guidance for further experiments in this nuclei region.

A nuclear physics example of statistical bootstrap is used on the MARATHON nucleon structure function ratio data in the quark momentum fraction regions $x_B\to 0$ and $x_B\to 1$. The extrapolated $F_2$ ratio as quark momentum fraction $x_B\to 1$ is $\frac{F_2^n}{F_2^p}\to 0.4\pm 0.05$ and this value is compared to theoretical predictions. The extrapolated ratio when $x_B\to 0$ favors the simple model of isospin symmetry with the complete dominance of sea quarks at low momentum fraction. At high-$x_B$, the proton quark distribution function ratio $d/u$ is derived from the $F_2$ ratio and found to be $d/u\to 1/6$. Our extrapolated values for both the $\frac{F_2^n}{F_2^p}$ ratio and the $d/u$ parton distribution function ratio are within uncertainties of perturbative QCD values from quark counting, helicity conservation arguments, and a Dyson-Schwinger equation with a contact interaction model. In addition, it is possible to match the statistical bootstrap value to theoretical predictions by allowing two compatible models to act simultaneously in the nucleon wave function. One such example is nucleon wave functions composed of a linear combination of a quark-diquark state and a three-valence quark correlated state with coefficients that combine to give the extrapolated $F_2$ ratio at $x_B=1$.

In a recent work [H. Zhang, D. Bai, Z. Wang, and Z. Ren, Phys. Rev. C 105, 054317 (2022)], the complex scaled nonlocalized cluster model (CSNLCM) is proposed to study the resonant cluster states. In this work, we improve CSNLCM by combining it with the continuum level density (CLD). While the original CSNLCM gives the structural observables for resonant cluster states, the improved model (named CSNLCM-CLD) can give both the scattering observables such as phase shifts and the resonance observables. We take the $\alpha +\alpha$ system as an example to validate the formalism of CSNLCM-CLD and benchmark the theoretical results with the conventional microscopic $R$-matrix method. Good agreement is achieved, which shows the reliability of CSNLCM-CLD. There is also good agreement between our improved model (CSNLCM-CLD) and the experimental data.

The neutrino mean free path is evaluated in hot proto–neutron star matter under a strong magnetic field. We consider densities in the range $0.04\le \rho \le 0.4{\mathrm{fm}}^{-3}$, several proton fractions from symmetric matter up to pure neutron matter, temperatures up to 30 MeV, and two magnetic field strengths $B={10}^{17}$ and ${10}^{18}$ G. Polarized proto–neutron star matter is described within the nonrelativistic Hartree-Fock model using the LNS Skyrme interaction, where the proper treatment for instabilities for low densities and temperatures is implemented. Under the same conditions, the degree of polarization of protons is stronger than the one for neutrons. For the neutrino mean free path we consider three reactions: the neutrino-neutron and neutrino-proton scattering, $\nu +n\to {\nu }^{\prime }+n^{\prime }$ and $\nu +p\to {\nu }^{\prime }+p^{\prime }$, respectively, and the neutrino absorption reaction $\nu +n\to e^{-}+p$. The magnetic field induces an asymmetry in the mean free path which favors the flux of neutrinos parallel to the magnetic field in the case of neutron scattering and the absorption reaction, whereas it is antiparallel in the case of proton scattering. For most of the conditions the absorption reaction is the dominant one. The dependence of the neutrino mean free path on the magnetic field, the temperature, and the proton fraction is different for each reaction. As a representative case of our results, the asymmetry in the mean free path is $\approx 21\%$ at saturation density for $B={10}^{18}$ G, $T=15$ MeV, and symmetric matter, while we have $\approx -1\%$ for $B={10}^{17}$ G and the same values of all the other conditions.

The ${}^{77}\mathrm{Se}(n,\gamma )$ reaction is of importance for ${}^{77}\mathrm{Se}$ abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the ${}^{77}\mathrm{Se}$ radiative neutron capture cross section at the Neutron Time-of-Flight facility at CERN. Resonance capture kernels were derived up to 51 keV and cross sections up to 200 keV. Maxwellian-averaged cross sections were calculated for stellar temperatures between $kT=5\mathrm{keV}$ and $kT=100\mathrm{keV}$, with uncertainties between 4.2% and 5.7%. Our results lead to substantial decreases of 14% and 19% in ${}^{77}\mathrm{Se}$ abundances produced through the slow neutron capture process in selected stellar models of $15M_{\odot }$ and $2M_{\odot }$, respectively, compared to using previous recommendation of the cross section.

The higher-order cumulants of net-proton number, net-charge, and net-strangeness multiplicity distributions are widely studied to search for the quantum-chromodynamics critical point and extract the chemical freeze-out parameters in heavy-ion collisions. In this context, the event-by-event fluctuations of the net-strangeness multiplicity distributions play important roles in extracting the chemical freeze-out parameter in the strangeness sector. Due to having difficulties in detecting all strange hadrons event by event, the kaon $\left(K\right)$ and lambda $\left(\mathrm{\Lambda }\right)$ particles serve as a proxy for the strangeness-related observables in heavy-ion collisions. We have studied the $\mathrm{net}\text{−}K$, $\mathrm{net}\text{−}\mathrm{\Lambda }$, and net-$(K+\mathrm{\Lambda })$ multiplicity distributions and calculated their different order of cumulants using the ultrarelativistic quantum molecular dynamics model and hadron resonance gas calculation. To adequately account for the net-strangeness cumulants, it has been found that the inclusion of resonance decay contributions in $K$ and $\mathrm{\Lambda }$ is necessary.

A ground-state rotational band in the fissile nucleus ${}^{254}\mathrm{Rf}$ was observed for the first time. Levels up to spin $14\hslash$ and excitation energy of 1.56 MeV were observed. The ${}^{254}\mathrm{Rf}$ nuclei were produced using the ${}^{206}\mathrm{Pb}({}^{50}\mathrm{Ti},2n)$ fusion-evaporation reaction. It is the weakest reaction channel ever studied using in-beam $\gamma$-ray spectroscopic methods. The reaction products were separated from the beam in the Argonne gas-filled analyzer (AGFA). The ${}^{254}\mathrm{Rf}$ nuclei were implanted into a double-sided Si strip detector at the AGFA focal plane and tagged with subsequent ground-state spontaneous fission decays using temporal and spatial correlations. Prompt $\gamma$ rays in coincidence with the ${}^{254}\mathrm{Rf}$ recoils were detected in the Gammasphere array of Ge detectors. In order to identify the ground-state rotational band in ${}^{254}\mathrm{Rf}$, a method for identifying rotational bands in low statistics $\gamma$-ray spectra was developed. The deduced ${}^{254}\mathrm{Rf}$ kinematic moment of inertia is smaller compared to neighboring even-even nuclei. This is most likely associated with a slightly lower quadrupole deformation and stronger pairing correlations in ${}^{254}\mathrm{Rf}$. The behavior of the moment of inertia as a function of rotational frequency is similar to that of the lighter $N=150$ isotones ${}^{250}\mathrm{Fm}$ and ${}^{252}\mathrm{No}$.

Following the construction approach to successfully describe the $B\left(E2\right)$ anomaly in the interacting boson model with SU(3) higher-order interactions, the O(6) higher-order interactions are also considered to be used to investigate this anomaly, but the numerical calculations show that this construction approach is unphysical. This implies that O(6) symmetry is insufficient to construct a general theory to describe the collective properties in nuclei.

Accelerator-based techniques are one of the leading ways to produce radioactive nuclei. In this work, the isotope separation on-line method was employed at the CERN-ISOLDE facility to produce neptunium and plutonium from a uranium carbide target material using 1.4-GeV protons. Neptunium and plutonium were laser-ionized and extracted as 30-keV ion beams. A multireflection time-of-flight mass spectrometer was used for ion identification by means of time-of-flight measurements as well as for isobaric separation. Isotope shifts were investigated for the 395.6-nm ground state transition in ${}^{236,237,239}\mathrm{Np}$ and the 413.4-nm ground state transition in ${}^{236,239,240}\mathrm{Pu}$. Rates of ${}^{235–241}\mathrm{Np}$ and ${}^{234–241}\mathrm{Pu}$ ions were measured and compared with predictions of in-target production mechanisms simulated with geant4 and fluka to elucidate the processes by which these nuclei, which contain more protons than the target nucleus, are formed. ${}^{241}\mathrm{Pu}$ is the heaviest nuclide produced and identified at a proton-accelerator-driven facility to date. We report the availability of neptunium and plutonium as two additional elements at CERN-ISOLDE and discuss the limit of accelerator-based isotope production at high-energy proton accelerator facilities for nuclides in the actinide region.

The measurement of the production of deuterons, tritons and ${}^3\mathrm{He}$ and their antiparticles in Pb-Pb collisions at $\sqrt{s_{NN}}=5.02\mathrm{TeV}$ is presented in this article. The measurements are carried out at midrapidity $\left(\right|y|< 0.5)$ as a function of collision centrality using the ALICE detector. The $p_{\mathrm{T}}$-integrated yields, the coalescence parameters and the ratios to protons and antiprotons are reported and compared with nucleosynthesis models. The comparison of these results in different collision systems at different center-of-mass collision energies reveals a suppression of nucleus production in small systems. In the Statistical Hadronisation Model framework, this can be explained by a small correlation volume where the baryon number is conserved, as already shown in previous fluctuation analyses. However, a different size of the correlation volume is required to describe the proton yields in the same data sets. The coalescence model can describe this suppression by the fact that the wave functions of the nuclei are large and the fireball size starts to become comparable and even much smaller than the actual nucleus at low multiplicities.

We investigate double-strangeness exchange reactions, $K^{-}p\to K^{+}{\mathrm{\Xi }}^{-}$ and $K^{-}p\to K^0{\mathrm{\Xi }}^0$, using an effective Lagrangian approach based on a hybrid Regge-plus-resonance model involving rescattering diagrams. We consider the background processes that include $\mathrm{\Lambda }$, $\mathrm{\Sigma }$, and $\mathrm{\Sigma }\left(1385\right)$ Regge trajectories in the $u$ channel and the $s$-channel Born-term diagrams. The $s$-channel hyperon resonances account for the bump structures in the total cross sections. The $s$-channel $\mathrm{\Lambda }(2100,7/2^{-})$ and $\mathrm{\Sigma }(2030,7/2^{+})$ resonances contribute significantly, and the $\mathrm{\Sigma }\left(2250\right)$ resonance favors $J^P=7/2^{-}$. The interference pattern between the $\mathrm{\Lambda }(2100,7/2^{-})$ and $\mathrm{\Sigma }(2030,7/2^{+})$ amplitudes is essential for describing forward differential cross sections in the resonance region $2.07<\sqrt{s}<2.15\mathrm{GeV}$. The absence of the $S=-2$ meson leads to the inclusion of the meson-baryon rescattering diagrams to describe the $K^{-}p\to K\mathrm{\Xi }$ reaction data, proving the significant contribution of the $(\varphi ,\rho ,\omega )$–$(\mathrm{\Lambda },\mathrm{\Sigma })$ rescattering diagrams.

Both the Coulomb interaction and isospin symmetry breaking (ISB) parts of the nuclear interaction break the isospin symmetry in atomic nuclei. Effects of these two kinds of interaction on properties of atomic nuclei, especially the mass difference of mirror nuclei and the neutron-skin thickness of $N=Z$ and $N\ne Z$ nuclei, are discussed. It is found that corrections to the Hartree-Fock-Slater approximation for the Coulomb interaction negligibly affect the neutron-skin thickness, while the charge-symmetry breaking term originating from the strong interaction might affect it non-negligibly. According to our calculations, the ISB terms other than the Coulomb interaction affect the estimation of the density dependence of the symmetry energy, $L$, by about $0–12\mathrm{MeV}$ using the correlation with the neutron-skin thickness.

Forthcoming experiments such as Project 8 and Ptolemy aim at investigating with high precision the end point of the tritium $\beta$-decay spectrum sensitive to the neutrino mass. In light of this, using the standard parametrization in terms of nuclear polar form factors, we analyze the complete relativistic expression for the spectrum of the $\beta$ electron emitted by a tritium nucleus. Given the small parameters in the problem, we systematically discuss the approximations that can be made, and present the first two corrections to the standard lowest-order formula. We particularly discuss the case of an initially polarized target, and the consequences on the spectrum as a function of the neutrino mass. We show that, while it induces an angular anisotropy that can be measured by future experiments, such anisotropy cannot be used as an additional handle to constrain the neutrino mass.

We discuss mean field theory of quarkyonic matter at zero temperature. We treat the nucleons with contact interactions in mean field approximation, discussing both vector and scalar mean field interactions. We treat the quarks without mean field vector interactions, but allow mass terms to be generated consistently from a scalar mean field consistent with the additive quark model for quark masses. Quarkyonic matter is composed of a shell of nucleons that under-occupy the total available phase space associated with the underlying quark degrees of freedom. The fully occupied Fermi sphere beneath this shell of nucleons at high densities is thought of as quarks, but when this fully occupied distribution of states first appears, although the phase space is filled, the matter is at low density. For the transition between this low density and high density saturated matter, we advocate a dual description of the fully filled Fermi sea in terms of hadrons, and make a phenomenological hypothesis for the equation of state of this matter. We then proceed to an example where the mean field interactions are all vector and only associated with the nucleons, ignoring the effects of mass change associated with the scalar interactions. Except for the effects of Pauli blocking, the nucleons and quarks do not interact. To get a reasonable transition to quarkyonic matter the interaction of the quarks among themselves are assumed to be nonperturbative, and a simple phenomenological relation between quark Fermi energy and density is introduced.

The strength of the narrow resonance of the ${}^{13}\mathrm{C}(\alpha ,n){}^{16}\mathrm{O}$ reaction at $E_{\alpha }=1055.63$ keV is determined to be $16.9\pm 0.4\left(\mathrm{stat}\right)\pm 1.7\left(\text{sys}\right)$ eV. The resonance strength and the cross section in the vicinity of the resonance are used to reconcile inconsistencies of past measurements. Our normalization factors agree with the recommendation of the ENDF/B-VIII.0 evaluation and the CIELO project. The sum of the resonance strengths of the two narrow resonances around $E_{\alpha }=1336$ keV is also determined to be $57.3\pm 4.8\left(\mathrm{stat}\right)\pm 5.7\left(\text{sys}\right)$ eV.