The charged-current quasi-elastic scattering of muon neutrinos on an oxygen target is computed for neutrino energies between 200 MeV and 2.5 GeV using the relativistic distorted-wave impulse approximation with relativistic optical potential, which was earlier successfully applied to describe electron-nucleus data. We study both neutrino and electron processes and show that the reduced exclusive cross section for neutrino and electron scattering are similar. The comparison with the relativistic Fermi gas model (RFGM), which is widely used in data analyses of neutrino experiments, shows that the RFGM fails completely when applied to exclusive cross section data and leads to overestimated values of inclusive and total cross sections. We also found significant nuclear-model dependence of exclusive, inclusive, and total cross sections for about 1 GeV energy.

By adopting a finite square-well potential, the analytic expressions of $\mathit{dB}(E1)/{\mathit{dE}}_x$ for the cases of ${\ell }_h=0\to {\ell }_c=1,{\ell }_h=1\to {\ell }_c=0,{\ell }_h=1\to {\ell }_c=2$, and ${\ell }_h=2\to {\ell }_c=1$ are derived in the distorted wave approximation (DWA). From these analytic expressions it can be seen clearly that enhanced low-lying $B(E1)$ strengths in nuclei near drip-line mainly come from the orbits with small binding energy and small angular momentum. Comparing the results of analytic expressions with the experimental $\mathit{dB}(E1)/{\mathit{dE}}_x$ data, the spectroscopic factors of the $2s_{1/2}$ state in ${}^{11}\mathrm{Be}$ were deduced as 0.92, 0.87, and 0.83 for the well depths $U_0=50$ MeV, 40 MeV, and 33 MeV, respectively.

Within the optical model for direct reactions, simultaneous calculations of elastic scattering, complete fusion, and total reaction cross sections for energies around the Coulomb barrier are presented for reactions involving the weakly bound projectile ${}^9\mathrm{Be}$ on ${}^{64}\mathrm{Zn}$. Volume ($W_F$) and surface ($W_{\mathrm{DR}}$) Woods-Saxon optical potentials are used such that the former is responsible only for complete fusion reactions while the latter for all direct reactions plus incomplete fusion. Simultaneous fits can be obtained with several sets of potential parameters, but if we impose the condition that the strength of $W_F$ is smaller than the strength of $W_{\mathrm{DR}}$ at the tail region of the potential (this condition is discussed in detail), then values are required for $r_F$ and $r_{\mathrm{DR}}$ of around $1.6$ and 1.7–1.9 fm, respectively. These values are much larger than those frequently used in barrier penetration model calculations. Through the energy dependence of the real and imaginary parts of the polarization potentials, we show that the usual threshold anomaly does not show up for this system, but instead there is evidence of the presence of a breakup threshold anomaly.

The ${}^{29}\mathrm{P}$($p,\gamma$)${}^{30}\mathrm{S}$ reaction rate affects the interpretation of nova Si abundances, which have been precisely measured in presolar grains. The rate is thought to be dominated by previously unobserved $3^{+}$ and $2^{+}$ resonances above the ${}^{30}\mathrm{S}$ proton threshold at 4399 keV. To better understand the ${}^{29}\mathrm{P}$($p,\gamma$)${}^{30}\mathrm{S}$ rate, we have studied the ${}^{30}\mathrm{S}$ nucleus with the ${}^{32}\mathrm{S}$($p,t$)${}^{30}\mathrm{S}$ reaction. We have observed 13 ${}^{30}\mathrm{S}$ levels, nine of which are above the proton threshold, including a level at 4704 keV that is a candidate to be the important $3^{+}$ resonance. We also resolve a significant discrepancy between previously published excitation energies. From the observed triton angular distributions, we constrain the spins of several levels, ruling out several previous hypotheses and constraining some for the first time. Using our updated information, we estimate the ${}^{29}\mathrm{P}$($p,\gamma$)${}^{30}\mathrm{S}$ reaction rate is approximately six times larger at nova temperatures than previously thought.

The ${}^{26}\mathrm{Al}$($n,\alpha$)${}^{23}\mathrm{Na}$ reaction cross section has been studied at the linear accelerator GELINA of the Institute for Reference Materials and Measurements in Geel, Belgium, and has been determined up to a neutron energy of about 100 keV using the time-of-flight technique. Six resonances could be observed in this energy region, whereas before only one had been identified experimentally. For four of them, resonance parameters such as resonance energy, total width, area, and spin of the state could be determined. From the obtained ${}^{26}\mathrm{Al}$($n,\alpha$)${}^{23}\mathrm{Na}$ cross section data, Maxwellian averaged cross section (MACS) values were calculated by numerical integration. Since neutron induced reactions are among the major destruction mechanisms of ${}^{26}\mathrm{Al}$ in our Galaxy, these new MACS values contribute to a better understanding of the observed ${}^{26}\mathrm{Al}$ abundance.

An exponential dependence of the fragmentation cross section on the average binding energy is observed and reproduced with a statistical model. The observed functional dependence is robust and allows the extraction of binding energies from measured cross sections. From the systematics of Cu isotope cross sections, the binding energies of ${}^{76,77,78,79}\mathrm{Cu}$ have been extracted. They are $636.94\pm 0.4,647.1\pm 0.4,651.6\pm 0.4$, and $657.8\pm 0.5$ MeV, respectively. Specifically, the uncertainty of the binding energy of ${}^{75}\mathrm{Cu}$ is reduced from 980 keV, as listed in the 2003 mass table of Audi, Wapstra, and Thibault to 400 keV. The predicted cross sections of two near drip-line nuclei, ${}^{39}\mathrm{Na}$ and ${}^{40}\mathrm{Mg}$ from the fragmentation of ${}^{48}\mathrm{Ca}$ are discussed.

In recent papers, we have proposed two different models to calculate fusion cross sections for heavy-ion systems, based on coupled-channels calculations involving harmonic vibrations of the nuclear densities. The parameter-free São Paulo potential is assumed as the bare interaction and, therefore, the calculations are performed without any adjustable parameter. In the present work, we compare the results of these models in accounting for fusion data of approximately 60 different systems.

The Cornwall-Jackiw-Tomboulis (CJT) effective action approach is applied to study the phase transition of nuclear matter modeled by the four-nucleon interaction. It is shown that in the Hartree-Fock approximation (HFA) a first-order phase transition takes place at low temperature, whereas the phase transition is of second order at higher temperature.

The goal of this paper is to test and justify the use of the São Paulo potential model for calculating astrophysical $S$ factors for reactions involving stable and neutron-rich nuclei. In particular, we focus on the theoretical description of $S$ factors at low energies. This is important for evaluating the reaction rates in dense stellar matter. We calculate the $S$ factors for a number of reactions (${}^{16}\mathrm{O}+{}^{16}\mathrm{O}$, ${}^{20}\mathrm{O}+{}^{20}\mathrm{O}$, ${}^{20}\mathrm{O}+{}^{26}\mathrm{Ne}$, ${}^{20}\mathrm{O}+{}^{32}\mathrm{Mg}$, ${}^{26}\mathrm{Ne}+{}^{26}\mathrm{Ne}$, ${}^{26}\mathrm{Ne}+{}^{32}\mathrm{Mg}$, ${}^{32}\mathrm{Mg}+{}^{32}\mathrm{Mg}$, ${}^{22}\mathrm{O}+{}^{22}\mathrm{O}$, ${}^{24}\mathrm{O}+{}^{24}\mathrm{O}$) with the São Paulo potential in the framework of a one-dimensional barrier penetration model. This approach can be easily applied for many other reactions involving different isotopes. To test the consistency of the model predictions, we compare our calculations with those performed within the coupled-channels and fermionic molecular dynamics models. Calculated $S$ factors are parametrized by a simple analytic formula. The main properties and uncertainties of reaction rates (appropriate to dense matter in cores of massive white dwarfs and crusts of accreting neutron stars) are outlined.

The modification of the single inclusive spectrum of high transverse momentum ($p_T$) pions emanating from an ultrarelativistic heavy-ion collision is investigated. The deconfined sector is modeled using a full three-dimensional (3-D) ideal fluid dynamics simulation. Energy loss of high $p_T$ partons and the ensuing modification of their fragmentation is calculated within perturbative QCD at next-to-leading twist, where the magnitude of the higher twist contribution is modulated by the entropy density extracted from the 3-D fluid dynamics simulation. The nuclear modification factor ($R_{\mathit{AA}}$) for pions with a $p_T⩾8$ GeV as a function of centrality as well as with respect to the reaction plane is calculated. The magnitude of contributions to the differential $R_{\mathit{AA}}$ within small angular ranges, from various depths in the dense matter, is extracted from the calculation and demonstrates the correlation of the length integrated density and the $R_{\mathit{AA}}$ from a given depth. The significance of the mixed and hadronic phase to the overall magnitude of energy loss is explored.

In this Rapid Communication, we determine the fluctuations of the initial eccentricity in heavy-ion collisions caused by fluctuations of the nucleon configurations. This is done via a Monte Carlo implementation of a color glass condensate $k_t$-factorization approach. The eccentricity fluctuations are found to nearly saturate elliptic flow fluctuations measured recently at RHIC. Extrapolations to LHC energies are shown.

We have studied the positive-parity states of ${}^{40}\mathrm{Ca}$ using antisymmetrized molecular dynamics (AMD) and the generator coordinate method (GCM). Imposing two different kinds of constraints on the variational calculation, we have found various kinds of ${}^{40}\mathrm{Ca}$ structures such as a deformed-shell structure, as well as $\alpha \text{−}$${}^{36}\mathrm{Ar}$ and ${}^{12}\mathrm{C}$-${}^{28}\mathrm{Si}$ cluster structures. After the GCM calculation, we obtained a normal-deformed band and a superdeformed band together with their side bands associated with triaxial deformation. The calculated $B(E2)$ values agreed well with empirical data. It was also found that the normal-deformed and superdeformed bands have non-negligible $\alpha \text{−}$${}^{36}\mathrm{Ar}$ cluster and ${}^{12}\mathrm{C}$-${}^{28}\mathrm{Si}$ cluster components, respectively. This leads to the presence of an $\alpha \text{−}$${}^{36}\mathrm{Ar}$ higher nodal band occurring above the normal-deformed band.

It is shown that particle-triaxial-rotor calculations with a Woods-Saxon potential for ${}^{195}\mathrm{Pt}$ reproduce the experimentally observed doublet structure of the excitation spectrum below 700 keV. The observed strong $B(E2)$ transition strengths are also well reproduced. The structure of every doublet is dominated by one out of two single-particle orbitals. The absolute values of the $E2$ transition probabilities obtained in the particle-rotor model are in overall agreement with the predictions made by assuming a U(6/12) supersymmetry. The ratios of $B(E2)$ values between the states of two doublets agree well with those obtained by assuming a pseudospin symmetry only. This supports the idea of a pseudospin nature of the doublet structure although no a priori assumptions are made concerning a pseudospin symmetry of the Hamiltonian.

We analyze the evolution with increasing isospin asymmetry of the proton single-particle states $2s1/2$ and $1d3/2$ in Ca isotopes, using nonrelativistic and relativistic mean-field approaches. Both models give similar trends and it is shown that this evolution is sensitive to the neutron shell structure, the two states becoming more or less close depending on the neutron orbitals that are filled. In the regions where the states get closer some parametrizations lead to an inversion between them. This inversion occurs near ${}^{48}\mathrm{Ca}$ as well as very far from stability where the two states systematically cross each other if the drip line predicted in the model is located far enough. We study in detail the modification of the two single-particle energies by using the equivalent potential in the Schroedinger-like Skyrme-Hartree-Fock equations. The role played by central, kinetic, and spin-orbit contributions is discussed. We finally show that the effect of a tensor component in the effective interaction considerably favors the inversion of the two proton states in ${}^{48}\mathrm{Ca}$.

We calculate densities of excited states in the quasiparticle random-phase approximation (QRPA) with Skyrme interactions and volume pairing. We focus on low-energy peaks/bumps in the strength functions of a range of Ca, Ni, and Sn isotopes for $J^{\pi }=0^{+},1^{-}$, and $2^{+}$. We define an “emitted-neutron number,” which we then use to distinguish localized states from scattering-like states. The degree of delocalization either increases as the neutron-drip line is approached or stays high between the stability line and the drip line. In the $2^{+}$ channel of Sn, however, the low-lying states, not even counting surface vibrations, are still fairly well localized on average, even at the neutron drip line.

The isothermal compression of a dilute nucleonic gas invoking cluster degrees of freedom is studied in an equilibrium statistical model; this clusterized system is found to be more stable than the pure nucleonic system. The equation of state (EoS) of this matter, shows features qualitatively very similar to the one obtained from pure nucleonic gas. In the isothermal compression process, there is a sudden enhancement of clusterization at a transition density rendering features analogous to the gas-liquid phase transition in normal dilute nucleonic matter. Different observables like the caloric curves, heat capacities, isospin distillation, etc are studied in both the models. Possible changes in the observables due to recently indicated medium modifications in the symmetry energy are also investigated.

We study the properties of nonrotating and rotating neutron stars for a new set of equations of state (EOSs) with different high-density behavior obtained using the extended field theoretical model. The high-density behavior for these EOSs are varied by varying the ω-meson self-coupling and hyperon-meson couplings in such a way that the quality of fit to the bulk nuclear observables, nuclear matter incompressibility coefficient, and hyperon-nucleon potential depths remain practically unaffected. We find that the largest value for maximum mass for the nonrotating neutron star is $2.1M_{\odot }$. The radius for a neutron star with canonical mass is 12.8–14.1 km, provided only those EOSs are considered for which the maximum mass is larger than $1.6M_{\odot },$ the lower bound on the maximum mass measured so far. Our results for the very recently discovered fastest rotating neutron star indicate that this star is supramassive with mass $1.7M_{\odot }$–$2.7M_{\odot }$ and circumferential equatorial radius 12–19 km.

The instability of nuclear matter due to particle-hole excitation modes has been studied in the framework of several relativistic mean-field (RMF) models. It is found that both the longitudinal and the transversal modes depend sensitively on the parameter sets used. The important impact of the vector and vector-scalar nonlinear terms on the stability of both modes is demonstrated. Our finding corroborates the result of previous studies, namely that certain RMF models cannot be used in high-density applications. However, we show that for certain parameter sets of RMF models this shortcoming can be alleviated by adding these nonlinear terms.

In the present work, we take the nonrelativistic limit of relativistic models and compare the obtained functionals with the usual Skyrme parametrization. Relativistic models with both constant couplings and with density-dependent couplings are considered. While some models already present very good results at the lowest order in the density, models with nonlinear terms only reproduce the energy functional if higher order terms are taken into account in the expansion.

The equation of state (EOS) of quark-gluon plasma (QGP) using the Cornell potential based on Mayer's cluster expansion is presented. The string constant and the strong coupling constant for QGP are calculated. The EOS developed could describe the lattice EOS for pure gauge, two-flavor and three-flavor QGP qualitatively.