We discuss the effect of a strong magnetic field on neutron ${}^{3}P_2$ superfluidity. Based on the attraction in the ${}^{3}P_2$ pair of two neutrons, we derive the Ginzburg–Landau equation in the path-integral formalism by adopting the bosonization technique and leave the next-to-leading order in the expansion of the magnetic field $B$. We determine the $(T,B)$ phase diagram with temperature $T$, comprising three phases: the uniaxial nematic (UN) phase for $B=0, {\mathrm{D}}_2$-biaxial nematic (BN) and ${\mathrm{D}}_4$-BN phases in finite $B$ and strong $B$ such as magnetars, respectively, where ${\mathrm{D}}_2$ and ${\mathrm{D}}_4$ are dihedral groups. We find that, compared with the leading order in the magnetic field known before, the region of the ${\mathrm{D}}_2$-BN phase in the $(T,B)$ plane is extended by the effect of the next-to-leading-order terms of the magnetic field. We also present the thermodynamic properties, such as heat capacities and spin susceptibility, and find that the spin susceptibility exhibits anisotropies in the UN, ${\mathrm{D}}_2$-BN, and ${\mathrm{D}}_4$-BN phases. This information will be useful to understand the internal structure of magnetars.

This paper is an addendum to a recent publication on charged-current neutrino-induced pion production [Phys. Rev. C 96, 015503 (2017)]. It presents comparisons of pion production cross sections measured at the T2K near detector for a CH target.

We investigate the properties of baryons within the framework of the in-medium modified SU(3) Skyrme model. The modification is performed by a minimal way, the medium functionals in the SU(2) sector being introduced. These functionals are then related to nuclear matter properties near the saturation point. The modifications in the SU(3) sector are performed by changing additionally kaon properties in nuclear matter. The results show that the properties of baryons in the strange sector are sensitive to the in-medium modifications of the kaon properties. We discuss the consistency of the in-medium modifications of hadron properties in this approach, comparing the present results with those from other models.

Absolute cross sections for 22 fissionlike fragments concerning their decay mode via independent and cumulative cross sections have been measured at four projectile energies, i.e., $82.2\pm 0.8,79.18\pm 0.82,76.8\pm 1.2$, and $72.9\pm 0.91\mathrm{MeV}$. The recoil-catcher activation technique followed by offline $\gamma$-ray spectrometry was employed. The isotopic yield distribution and the variance for indium isotopes have been obtained from the experimental data and were found to be in agreement with the literature values. The fissionlike fragments mass distribution is found to be a single-peaked Gaussian distribution and confirms their population via deexcitation of the compound nucleus. The mass distribution variance is found to be narrower and exponentially increases as compared to relatively heavier systems at above 20% of the Coulomb barrier. A self-consistent approach for determining the isobaric charge dispersion parameters has been adopted. The present paper suggests that fission is one of the competing modes at low energies other than complete fusion and incomplete fusion processes.

Magnetic form factors corresponding to elastic electron scattering from odd-$A$ nuclei are presented. The calculations are carried out in plane-wave Born approximation. The one-body properties are obtained in a deformed self-consistent mean-field calculation based on a Skyrme HF+BCS method. Collective effects are also included in the cranking approximation. Results on several stable nuclei are compared with the available experimental information. It is shown that a deformed formalism improves the agreement with experiment in deformed nuclei, while reproducing equally well spherical nuclei by taking properly the spherical limit of the deformed model and the effect of nucleon-nucleon correlations. Thus, the capability of the model to describe magnetic form factors is demonstrated. This opens the door to explore also unstable nuclei of particular interest that could be measured in future experiments on electron-radioactive beam colliders.

Evaporation residue cross sections for the ${}^{16}\mathrm{O}+{}^{203,205}\mathrm{Tl}$ reactions were measured at laboratory beam energies in the range of 82–113 MeV using a gas-filled separator. Transmission efficiency of the separator was estimated using a calibration reaction ${}^{16}\mathrm{O}+{}^{197}\mathrm{Au}$ and by simulating the evaporation residues angular distributions. Statistical model calculations were performed for both the measured systems. These calculations overestimate the experimental evaporation residue cross sections. This could be attributed to the presence of noncompound nuclear fission. An estimation of noncompound nuclear fission contribution was carried out. Comparison with neighboring systems shows that a slight change in the entrance channel or the compound nucleus properties makes a large difference in evaporation residue cross sections.

Background: The ${}^7\mathrm{Li}(p,n){}^7\mathrm{Be}$ reaction is one of the most used nuclear reaction for accelerator-based neutron sources. There are few experimental cross section data in the double-value energy region and they are discrepant, as are the reaction yields.

Purpose: We derive the ${}^7\mathrm{Li}(p,n){}^7\mathrm{Be}$ reaction cross section, and measure with small uncertainty the ${}^{197}\mathrm{Au}(n,\gamma ){}^{198}\mathrm{Au}$ spectrum-averaged cross section at neutron energy around 30 keV.

Method: By irradiating Li metal targets over the proton energy range of 1879 to 1960 keV, thick target yields were measured using the generated ${}^7\mathrm{Be}$ activity. Based on the theoretical description of the reaction yield, accelerator parameters and reaction cross sections are derived. Gold foils were activated with the neutron field generated by the $(p,n)$ reaction on a Li target at a proton energy of about a half keV above the reaction threshold.

Results: The thick target yield is well reproduced when the Breit-Wigner single-resonance formula for $s$-wave particles is used to describe the reaction cross section. The ratio between neutron and proton widths was found to be equal to ${\mathrm{\Gamma }}_n/{\mathrm{\Gamma }}_p=5.4\sqrt{1-T_{th}/T_p}$. The detailed balance principle is used to obtain the cosmologically important time-reversed ${}^7\mathrm{Be}(n,p){}^7\mathrm{Li}$ reaction cross section. The measured ${}^{197}\mathrm{Au}(n,\gamma ){}^{198}\mathrm{Au}$ spectrum-averaged cross section agrees with the value calculated from the ENDF/B-VIII.0 library.

Conclusions: We demonstrated the feasibility of deriving the ${}^7\mathrm{Li}(p,n){}^7\mathrm{Be}$ reaction cross section from the thick target yield. Using the ratio between neutron and proton widths obtained in this work reduces the uncertainty in calculating the reaction cross section to a factor of 2.3.

A study of the meson-baryon interaction in the $S=-1$ sector is performed, employing a chiral SU(3) Lagrangian up to next-to-leading order (NLO) and implementing unitarization in coupled channels. The model is constrained by a large set of experimental data, paying special attention to processes that are sensitive to the NLO contributions, such as the $K^{-}p\to K^{+}{\mathrm{\Xi }}^{-},K^0{\mathrm{\Xi }}^0$ reactions. The consideration of additional cross sections in single isospin channels, $K^{-}p\to \eta \mathrm{\Lambda },\eta \mathrm{\Sigma }$, has been found to provide NLO low-energy constants of rather similar size. The stability of these constants has also been tested by the inclusion of explicit resonant terms. Predictions for new isospin filtering processes, like the $I=1K_L^{0}p\to K^{+}{\mathrm{\Xi }}^0$ reaction that could be measured at the proposed secondary $K_L^0$ beam at Jlab, or the weak decay of the ${\mathrm{\Lambda }}_b$ into a $J/\mathrm{\Psi }$ and different meson-baryon pairs in $I=0$, available at LHCb, are presented. The measurement of such reactions would put valuable constraints on the chiral models describing the $S=-1$ meson-baryon interaction.

The magnetic form factors of ${}^2\mathrm{H},{}^3\mathrm{H}$, and ${}^3\mathrm{He}$, deuteron photodisintegration cross sections at low energies, and deuteron threshold electrodisintegration cross sections at backward angles in a wide range of momentum transfers are calculated with the chiral two-nucleon (and three-nucleon) interactions including $\mathrm{\Delta }$ intermediate states that have recently been constructed in configuration space. The $A=3$ wave functions are obtained from hyperspherical-harmonics solutions of the Schrödinger equation. The electromagnetic current includes one- and two-body terms, the latter induced by one- and two-pion exchange (OPE and TPE, respectively) mechanisms and contact interactions. The contributions associated with $\mathrm{\Delta }$ intermediate states are only retained at the OPE level and are neglected in TPE loop (tree-level) corrections to two-body (three-body) current operators. Expressions for these currents are derived and regularized in configuration space for consistency with the interactions. The low-energy constants that enter the contact currents are determined by reproducing the magnetic moments of these few-nucleon systems. The predicted form factors and deuteron electrodisintegration cross section are in excellent agreement with experiment for momentum transfers up to 2–$3{\mathrm{fm}}^{-1}$. However, the experimental values for the deuteron photodisintegration cross section are consistently underestimated by theory, unless use is made of the Siegert form of the electric dipole transition operator. A complete analysis of the results is provided, including the clarification of the origin of the aforementioned discrepancy.

In ${}^{208}\mathrm{Pb}$, 14 states at $E_x\approx 6.0\mathrm{MeV}$ are identified as members of a multiplet where the one-particle one-hole configuration $g_{9/2}{p}_{1/2}$ is coupled to the $3^{-}$ yrast state. The coupling is described by the geometry of the recoupling of three spins and the large coupling strength of the one-particle one-hole configurations to the strongly collective $3^{-}$ yrast state.

Deformed multi-$\mathrm{\Lambda }$ hypernuclei are studied within a relativistic mean-field model. In this paper, I take some $N=Z$ “hyper-isotope” chains, i.e., ${}_{n\mathrm{\Lambda }}{}^{8+n}\mathrm{Be},{}_{n\mathrm{\Lambda }}{}^{20+n}\mathrm{Ne}$, and ${}_{n\mathrm{\Lambda }}{}^{28+n}\mathrm{Si}$ systems where $n=2,4$ for Be and $n=2,8$ for Ne and Si. A sign of two-${}_{2\mathrm{\Lambda }}{}^6\mathrm{He}$ cluster structure is observed in the two-body correlation in ${}_{4\mathrm{\Lambda }}{}^{12}\mathrm{Be}$. In the Ne hyper-isotopes, the deformation is slightly reduced by addition of $\mathrm{\Lambda }$ hyperons, whereas it is significantly reduced or even disappears in the Si hyper-isotopes.

We study the dynamic polarization potentials (DPPs) for 30.3 MeV protons and neutrons scattering from ${}^{40}\mathrm{Ca}$ that are generated by the coupling to deuteron channels. In this way we resolve unexpected differences from the general properties of such DPPs found in similar cases for lighter targets. It turns out that the contribution of particular states to the real part can change considerably with $Q$ value, coming close to changing sign. One consequence is the surprising result presented in Mackintosh and Keeley [Phys. Rev. C 97, 069901(E) (2018)], which is investigated here. The $Q$-value dependence of the DPPs also contributes to a substantial difference between the optical model potential for protons and neutrons, there being substantially different $Q$ values for ${}^{40}\mathrm{Ca}(n,d)$ and ${}^{40}\mathrm{Ca}(p,d)$ pickup reactions. The DPP calculations also enable a study of the dynamical nonlocality (distinct from exchange nonlocality) arising from pickup coupling. The characteristic properties of the DPPs for both protons and neutrons arising from nucleon pickup are also presented for incident nucleons at 25, 35, 40, and 45 MeV. All these properties vary with energy in a consistent way, including a change in the rms radius of the real potential, which, together with the general undularity of the DPP, shows that the pickup contributions cannot be represented by renormalizing a folding model potential.

A new Skyrme functional devised to account well for standard nuclear properties as well as for spin and spin-isospin properties is presented. The main novelty of this work relies on the introduction of tensor terms guided by ab initio relativistic Brueckner-Hartree-Fock calculations of neutron-proton drops. The inclusion of tensor term does not decrease the accuracy in describing bulk properties of nuclei, experimental data of some selected spherical nuclei such as binding energies, charge radii, and spin-orbit splittings can be well fitted. The new functional is applied to the investigation of various collective excitations such as the giant monopole resonance, the isovector giant dipole resonance, the Gamow-Teller resonance, and the spin-dipole resonance. The overall description with the new functional is satisfactory and the tensor terms are shown to be important particularly for the improvement of the spin-dipole resonance results. Predictions for the neutron skin thickness based on the nonenergy weighted sum rule of the spin-dipole resonance are also given.

We present an upgraded version of the SPY model, called SPY2 for version 2 of the scission point yield, to estimate mainly the yields and the kinetic energy distributions of fission fragments: The theoretical framework is similar to our previous version, i.e., a statistical scission point model, but this version is based on fully microscopic nuclear ingredients describing the fragments properties at the scission point. These include the static properties of some 7000 nuclei at 120 axial quadrupole deformations, such as binding energies, proton densities, single-particle level schemes, and states densities, coherently calculated within the constrained Hartree-Fock-Bogoliubov model on the basis of the Skyrme BSk27 interaction. The use of microscopic ingredients has been extended to the proton density distribution and the nuclear states densities. Considering realistic proton densities of fragments allows us to improve the definition of the scission point as well as the prediction of the kinetic energy distribution and to link the kinetic energy to the diffuseness of the fragments' proton density. New microscopic nuclear states densities improve the general coherence of the model, in particular regarding the inclusion of the odd-even pairing effect. In this updated SPY2 version, the calculation of the fission yields and kinetic energy distributions is significantly improved and found to be in relatively good agreement with experiments, at least qualitatively. A detailed study is performed for three well known fissioning systems, namely, thermal neutron induced fission of ${}^{235}\mathrm{U}$ and ${}^{239}\mathrm{Pu}$ and spontaneous fission of ${}^{252}\mathrm{Cf}$. A systematic analysis of the fission mode as well as mean fragments deformation and total kinetic energies has been performed for some 2000 fissioning nuclei with $78\le Z\le 110$ lying between the proton and neutron drip lines.

The scission neutron kinetic energy spectrum is calculated for ${}^{236}\mathrm{U}$ in the frame of the dynamical scission model. The bidimensional time-dependent Schrödinger equation with a time-dependent potential is used to propagate each neutron wave function during the scission process, which is supposed to last $1\times {10}^{-22}$ sec. At the end, we separate the unbound parts and continue to propagate them as long as possible (in this case $50\times {10}^{-22}$ sec) in the frozen fragments approximation. At several time intervals, the Fourier transforms of these wave packets are calculated in order to obtain the corresponding momentum distributions, which lead to the kinetic energy distributions. The evolution of these distributions in time provides an interesting insight into the separation of each neutron from the fissioning system and asymptotically gives the kinetic energy spectrum of that particular neutron. We group the results in substates with given projection $\mathrm{\Omega }$ of the angular momentum on the fission axis to study its influence on the spectrum. Finally, the sum over all $\mathrm{\Omega }$ values is compared with a typical evaporation spectrum as well as with recent precise measurements in the reaction ${}^{235}\mathrm{U}(n_{th},f)$. Structures are present both in the scission-neutron spectrum and in the data.

We report a new measurement of $D^0$-meson production at mid-rapidity $\left(\left|y\right|<1\right)$ in Au + Au collisions at $\sqrt{s_{\mathrm{NN}}}=200\mathrm{GeV}$ utilizing the heavy flavor tracker, a high resolution silicon detector at the STAR experiment. Invariant yields of $D^0$ mesons with transverse momentum $p_T\lesssim 9\mathrm{GeV}/c$ are reported in various centrality bins (0–10%, 10–20%, 20–40%, 40–60%, and 60–80%). Blast-wave thermal models are used to fit the $D^0$-meson $p_T$ spectra to study $D^0$ hadron kinetic freeze-out properties. The average radial flow velocity extracted from the fit is considerably smaller than that of light hadrons $(\pi ,K$, and $p)$, but comparable to that of hadrons containing multiple strange quarks $\left(\varphi ,{\mathrm{\Xi }}^{-}\right)$, indicating that $D^0$ mesons kinetically decouple from the system earlier than light hadrons. The calculated $D^0$ nuclear modification factors reaffirm that charm quarks suffer a large amount of energy loss in the medium, similar to those of light quarks for $p_T>4\mathrm{GeV}/c$ in central 0–10% Au + Au collisions. At low $p_T$, the nuclear modification factors show a characteristic structure qualitatively consistent with the expectation from model predictions that charm quarks gain sizable collective motion during the medium evolution. The improved measurements are expected to offer new constraints to model calculations and help gain further insights into the hot and dense medium created in these collisions.

The kaon-to-pion ratio $K^{+}/{\pi }^{+}$ and the scaled variance ${\omega }^{-}$ for fluctuations of negatively charged particles are studied within the statistical hadron resonance gas (HRG) model and the ultrarelativistic quantum molecular dynamics (urqmd) transport model. The calculations are done for $p+p,\text{Be}+\text{Be},\text{Ar}+\text{Sc}$, and $\text{Pb}+\text{Pb}$ collisions at the CERN Super Proton Synchrotron energy range to reveal the system-size dependence of hadron production. For the HRG calculations the canonical ensemble is imposed for all conserved charges. In the urqmd simulations the centrality selection in nucleus-nucleus collisions is done by calculating the forward energy $E_{\mathrm{F}}$ deposited in the Projectile Spectator Detector, and the acceptance maps of the NA61/SHINE detectors are used. The HRG and urqmd results are compared with the data of the NA61/SHINE Collaboration. To understand the difference in the event-by-event fluctuations in $p+p$ and heavy-ion collisions, the centrality-selection procedure in the sample of all inelastic $p+p$ events is proposed and analyzed within the urqmd simulations.

The self-consistent quasiparticle model has been successful in studying QCD thermodynamics. In this model, the medium effects are taken into account by considering quarks and gluons as quasiparticles with temperature dependent masses which are proportional to the plasma frequency. The present work involves the extension of this model in the presence of magnetic fields. We have included the effect of the magnetic field by considering relativistic Landau levels. The quasiparticle masses are then found to be dependent on both temperature and magnetic field. The thermomagnetic mass thus defined allows us to obtain the thermodynamics of magnetized quark matter within the self-consistent quasiparticle model. The model then has been applied to the case of two-flavor quark-gluon plasma and the equation of state obtained in the presence of magnetic fields.

We present benchmark calculations of Zemach moments and radii of ${}^{2,3}\mathrm{H}$ and ${}^{3,4}\mathrm{He}$ using various few-body methods. Zemach moments are required to interpret muonic atom data measured by the CREMA collaboration at the Paul Scherrer Institute. Conversely, radii extracted from spectroscopic measurements can be compared with ab initio computations, posing stringent constraints on the nuclear model. For a given few-body method, different numerical procedures can be applied to compute these quantities. A detailed analysis of the numerical uncertainties entering the total theoretical error is presented. Uncertainties from the few-body method and the calculational procedure are found to be smaller than the dependencies on the dynamical modeling and the single nucleon inputs, which are found to be $\lesssim 2\%$. When relativistic corrections and two-body currents are accounted for, the calculated moments and radii are in very good agreement with the available experimental data.