Masses of ${}^{56,57}\mathrm{Fe}$, ${}^{53}\mathrm{Co}$${}^m$, ${}^{53,56}\mathrm{Co}$, ${}^{55,56,57}\mathrm{Ni}$, ${}^{57,58}\mathrm{Cu}$, and ${}^{59,60}\mathrm{Zn}$ have been determined with the JYFLTRAP Penning trap mass spectrometer at the Ion-Guide Isotope Separator On-Line facility with a precision of $\delta m/m⩽3\times {10}^{-8}$. The $Q_{\mathrm{EC}}$ values for ${}^{53}\mathrm{Co}$, ${}^{55}\mathrm{Ni}$, ${}^{56}\mathrm{Ni}$, ${}^{57}\mathrm{Cu}$, ${}^{58}\mathrm{Cu}$, and ${}^{59}\mathrm{Zn}$ have been measured directly with a typical precision of better than $0.7\hspace{0.5em}\mathrm{keV}$ and Coulomb displacement energies have been determined. The $Q$ values for proton captures on ${}^{55}\mathrm{Co}$, ${}^{56}\mathrm{Ni}$, ${}^{58}\mathrm{Cu}$, and ${}^{59}\mathrm{Cu}$ have been measured directly. The precision of the proton-capture $Q$ value for ${}^{56}\mathrm{Ni}$$(p,\gamma )$${}^{57}\mathrm{Cu}$, $Q_{(p,\gamma )}=689.69(51)\hspace{0.5em}\mathrm{keV}$, crucial for astrophysical $\mathit{rp}$-process calculations, has been improved by a factor of 37. The excitation energy of the proton-emitting spin-gap isomer ${}^{53}\mathrm{Co}$${}^m$ has been measured precisely, $E_x=3\hspace{0.5em}174.3(10)\hspace{0.5em}\mathrm{keV}$, and a Coulomb energy difference of $133.9(10)\hspace{0.5em}\mathrm{keV}$ for the $19/2^{-}$ state has been obtained. Except for ${}^{53}\mathrm{Co}$, the mass values have been adjusted within a network of 17 frequency ratio measurements between 13 nuclides, which allowed also a determination of the reference masses ${}^{55}\mathrm{Co}$, ${}^{58}\mathrm{Ni}$, and ${}^{59}\mathrm{Cu}$.

We present updated information and analysis for several states in ${}^{19}\mathrm{F}$ and ${}^{19}\mathrm{Ne}$ and correct a mistake in an earlier article.

We investigate proton-production double-differential cross sections (DDXs) for 300- and 392-MeV proton-induced reactions on O, V, Tb, Ta, Au, Pb, and Bi. Emitted proton energies are measured with stacked scintillator spectrometers by the $\Delta E-E$ technique. Experimental results are compared with the intranuclear cascade (INC) and quantum molecular dynamics models. Although both models can reproduce spectral DDXs, there is a difference at the most forward and backward angles. The cause of these differences is discussed in terms of the refraction caused by the nuclear potential. Angular distributions of the present data are well accounted for by the Kalbach systematics plus INC one-step calculations. The quasi-free-scattering contribution increases with decreasing target mass and increasing emission energy.

The article presents new measurements of low-energy resonances in the ${}^{16}\mathrm{O}$($\alpha ,\gamma$)${}^{20}\mathrm{Ne}$ reaction, which represents the endpoint for the reaction sequence responsible for energy production in stellar helium burning in massive red giant stars. The present data and previous unpublished data are analyzed in the framework of $R$-matrix theory to derive a reaction rate for the temperature regime of stellar helium burning.

The coherent-nuclear reaction $a+A\to a^{\star }+A$ is in the small-angle region dominated by the one-photon-exchange mechanism, often referred to as the Primakoff effect. In this region information about the electromagnetic decay $a^{\star }\to a+\gamma$ can be obtained. Well-known examples are the two-photon decays of the $\pi$ and $\eta$ mesons. Also, decays of charged hadrons can be studied. For charged hadrons the one-photon-exchange amplitude comes with a Coulomb-phase factor and a Coulomb-form factor, which depend on the ratio between transverse- and longitudinal-momentum transfers, the latter being fixed. At the peak of the cross-section distribution, where the two momentum transfers are equal, the form factor could cut down the cross-section value by as much as $40\%$. Consequently, a determination of a radiative-decay rate that relies on the peak value becomes sensitive to a proper treatment of the Coulomb-form factor.

We propose a simple systematics of low-lying $2_1^{+}$ energy levels and electromagnetic transitions in semimagic isotopic chains $Z=28,50,82$ and isotonic chains $N=28,50,82,126$. To this purpose we use a two-level pairing plus quadrupole Hamiltonian, within the spherical quasiparticle random phase approximation (QRPA). We derive a simple relation connecting the $2_1^{+}$ energy with the pairing gap and quadrupole-quadupole (QQ) interaction strength. It turns out that the systematics of energy levels and B(E2) values predicted by this simple model is fulfilled with a reasonable accuracy by all available experimental data. This systematics suggests that not only active nucleons but also those filling closed shells play an important role.

Angular distributions for the target spin-dependent observables $A_{0y}$, $A_{\mathit{xx}}$, and $A_{\mathit{yy}}$ have been measured using polarized proton beams at several energies between 2 and 6 MeV and a spin-exchange optical pumping polarized ${}^3\mathrm{He}$ target. These measurements have been included in a global phase-shift analysis following that of E. A. George and L. D. Knutson [Phys. Rev. C 67, 027001 (2003)], who reported two best-fit phase-shift solutions to the previous global $p+{}^3\mathrm{He}$ elastic-scattering database below 12 MeV. These new measurements, along with measurements of cross-section and beam-analyzing power made over a similar energy range by B. M. Fisher et al. [Phys. Rev. C 74, 034001 (2006)], allowed a single, unique solution to be obtained. The new measurements and phase shifts are compared with theoretical calculations using realistic nucleon-nucleon potential models.

Collective monopole vibrations are studied in the framework of an antisymmetrized version of molecular dynamics as a function of the vibration amplitude. The giant monopole resonance energy in ${}^{40}\mathrm{Ca}$ is sensitive to the incompressibility of the effective interaction, in good agreement with complete time-dependent Hartree-Fock calculations. The collective response of ${}^{12}\mathrm{C}$, ${}^{16}\mathrm{O}$, and ${}^{24}\mathrm{Mg}$ is also studied. For these lighter nuclei that have an important contribution of an $\alpha$-clustered component, different frequencies are observed, corresponding to two different types of vibrations associated with breathing and moving of the underlying clusters. Possible connections with direct breakup into $\alpha$ clusters at high excitation energy are discussed.

High spin states are observed for the first time in the neutron-rich nuclei ${}^{151,153}\mathrm{Pr}$, ${}^{157}\mathrm{Sm}$, and ${}^{93}\mathrm{Kr}$ from the spontaneous fission of ${}^{252}\mathrm{Cf}$. Twenty new transitions in ${}^{151}\mathrm{Pr}$, twelve in ${}^{153}\mathrm{Pr}$, five in ${}^{157}\mathrm{Sm}$, and four in ${}^{93}\mathrm{Kr}$ were identified by using x-ray(Pr/Sm)-$\gamma$-$\gamma$ and $\gamma$-$\gamma$-$\gamma$ triple coincidences. From the measured total internal conversion coefficients ${\alpha }_T$ of four low-energy transitions in ${}^{151,153}\mathrm{Pr}$, we determine that two bands in each nucleus have opposite parity. The interlacing $E1$ transitions between the bands suggest a form of parity doubling in ${}^{151,153}\mathrm{Pr}$. New bands in ${}^{157}\mathrm{Sm}$ and ${}^{93}\mathrm{Kr}$ are reported. The half-life of the 354.8 keV state in ${}^{93}\mathrm{Kr}$ is measured to be 10(2) ns.

The lowest order constrained variational technique has been used to investigate some of the thermodynamic properties of spin-polarized hot asymmetric nuclear matter, such as the free energy, symmetry energy, susceptibility, and equation of state. We have shown that the symmetry energy of the nuclear matter is substantially sensitive to the value of spin polarization. Our calculations show that the equation of state of the polarized hot asymmetric nuclear matter is stiffer for higher values of the polarization as well as the isospin asymmetry parameter. Our results for the free energy and susceptibility show that spontaneous ferromagnetic phase transition cannot occur for hot asymmetric matter.

We study reactions between neutron-rich ${}^{132}\mathrm{Sn}$ nucleus and ${}^{96}\mathrm{Zr}$ within a dynamic microscopic theory at energies in the vicinity of the ion-ion potential barrier peak, and we compare the properties to those of the stable system ${}^{124}\mathrm{Sn}$$+$${}^{96}\mathrm{Zr}$. The calculations are carried out on a three-dimensional lattice using the density-constrained time-dependent Hartree-Fock method. In particular, we calculate the dynamic excitation energy $E^{*}(t)$ during the initial stages of the collision. The barrier heights and widths of the heavy-ion potential increase substantially with $E_{\mathrm{c}.\mathrm{m}.}$ energy. The capture cross sections for the two reactions are of similar magnitude, but the interaction barrier for the neutron-rich system is found to be significantly (9 MeV) lower. A comparison with recently measured data is given.

The hot and dense medium formed in high energy heavy ion collisions may modify some hadronic properties. In particular, if hadron masses are shifted in-medium, it was demonstrated that this could lead to back-to-back squeezed correlations (BBC) of particle-antiparticle pairs. Although well-established theoretically, the squeezed correlations have not yet been discovered experimentally. A method has been suggested for the empirical search of this effect, which was previously illustrated for $\varphi \varphi$ pairs. We apply here the formalism and the suggested method to the case of $K^{+}{K}^{-}$ pairs, since they may be easier to identify experimentally. The time distribution of the emission process plays a crucial role in the survival of the BBC’s. We analyze the cases where the emission is supposed to occur suddenly or via a Lorentzian distribution, and compare with the case of a Lévy distribution in time. Effects of squeezing on the correlation function of identical particles are also analyzed.

Recently we showed that the centrality dependence of the multiplicity of different hadron species observed in Relativistic Heavy Ion Collider (RHIC) and Super Proton Synchrotron (SPS) experiments can be well understood in a simple model, dubbed the core-corona model. There it is assumed that those incoming nucleons that scatter only once produce hadrons as in pp collisions whereas those that scatter more often form an equilibrated source which decays according to phase space. In this article we show that also kinematical variables such as $v_2/{\epsilon }_{\mathrm{part}}(N_{\mathrm{part}})$ as well as $v_2^i/{\epsilon }_{\mathrm{part}}(N_{\mathrm{part}})$ and $\langle p_T^i(N_{\mathrm{part}})\rangle$ of identified particles are well described in this model. The correlation of $\langle p_T^i\rangle$ between peripheral heavy-ion collisions and pp collisions for different hadrons, reproduced in this model, questions whether hydrodynamical calculations are the proper tool to describe a noncentral heavy-ion collision. The model explains as well the centrality dependence of $v_2/{\epsilon }_{\mathrm{part}}$ of charged particles, considered up to now as an observable that allows us to determine the viscosity of the quark-gluon plasma. The observed dependence of $v_2^i/{\epsilon }_{\mathrm{part}}(N_{\mathrm{part}})$ on the particle species is a simple consequence of the different ratios of core-to-corona particles.

We study thermodynamics of nuclear matter in a two-flavored parity doublet model within the mean-field approximation. Parameters of the model are chosen to reproduce correctly the properties of the nuclear ground state. The model predicts two phase transitions in nuclear matter, a liquid-gas phase transition at normal nuclear density and a chiral transition at higher density. At finite temperature the pion decay constant exhibits a considerable reduction at intermediate values of chemical potential, which is traced back to the presence of the liquid-gas transition, and approaches zero at higher chemical potential associated with the chiral symmetry restoration. A “transition” from meson-rich to baryon-rich matter is also discussed.

The complex-rotated hyperspherical adiabatic method is used to study the decay of low-lying ${}^9\mathrm{Be}$ resonances into one neutron and two $\alpha$ particles. We investigate the six resonances above the breakup threshold and below 6 MeV: $1/2^{\pm }$, $3/2^{\pm }$, and $5/2^{\pm }$. The short-distance properties of each resonance are studied, and the different angular momentum and parity configurations of the ${}^8\mathrm{Be}$ and ${}^5\mathrm{He}$ two-body substructures are determined. We compute the branching ratio for sequential decay via the ${}^8\mathrm{Be}$ ground state, which qualitatively is consistent with measurements. We extract the momentum distributions after decay directly into the three-body continuum from the large-distance asymptotic structures. The kinematically complete results are presented as Dalitz plots as well as projections on given neutron and $\alpha$ energy. The distributions are discussed and, in most cases, found to agree with available experimental data.

We present simple equations for a canonical-basis (Cb) formulation of the time-dependent Hartree-Fock-Bogoliubov (TDHFB) theory. The equations are obtained from the TDHFB theory with an approximation that the pair potential is assumed to be diagonal in the Cb. The Cb formulation significantly reduces the computational cost. We apply the method to linear-response calculations for even-even light nuclei and demonstrate its capability and accuracy by comparing our results with recent calculations of the quasiparticle random-phase approximation with Skyrme functionals. We show systematic studies of $E1$ strength distributions for Ne and Mg isotopes. The evolution of the low-lying pygmy strength seems to be determined by the interplay of several factors, which include the neutron excess, the separation energy, the neutron-shell effects, the deformation, and the pairing.

The collision ${}^6\mathrm{He}+{}^{120}\mathrm{Sn}$ has been investigated at four energies near the Coulomb barrier. A large yield of $\alpha$ particles has been detected, with energies around the energy of the scattered ${}^6\mathrm{He}$ beam. The energy and angular distributions of the $\alpha$ particles have been analyzed and compared with breakup and neutron transfer calculations.

Global perturbative QCD analyses, based on large data sets from electron-proton and hadron collider experiments, provide tight constraints on the parton distribution function (PDF) in the proton. The extension of these analyses to nuclear parton distribution functions (nPDFs) has attracted much interest in recent years. nPDFs are needed as benchmarks for the characterization of hot QCD matter in nucleus-nucleus collisions, and attract further interest since they may show novel signatures of nonlinear density-dependent QCD evolution. However, it is not known from first principles whether the factorization of long-range phenomena into process-independent parton distribution, which underlies global PDF extractions for the proton, extends to nuclear effects. As a consequence, assessing the reliability of nPDFs for benchmark calculations goes beyond testing the numerical accuracy of their extraction and requires phenomenological tests of the factorization assumption. Here, we argue that a proton-nucleus collision program at the Large Hadron Collider would provide a set of measurements, which allow for unprecedented tests of the factorization assumption, underlying global nPDF fits.

We study the synchrotron radiation of gluons by fast quarks in strong magnetic field produced by colliding relativistic heavy ions. We argue that due to high electric conductivity of plasma, the magnetic field is almost constant during the entire plasma lifetime. We calculate the energy loss due to synchrotron radiation of gluons by fast quarks. We find that the typical energy loss per unit length for a light quark at the Large Hadron Collider is a few GeV per fm. This effect alone predicts quenching of jets with $p_{\perp }$ up to about 20 GeV. We also show that the spin-flip transition effect accompanying the synchrotron radiation leads to a strong polarization of quarks and leptons with respect to the direction of the magnetic field. Observation of the lepton polarization may provide a direct evidence of existence of strong magnetic field in heavy-ion collisions.

We study kinetic master equations for chemical reactions involving the formation and the natural decay of unstable particles in a thermal bath. We consider the decay channel of one into two particles and the inverse process, fusion of two thermal particles into one. We present the master equations for the evolution of the density of the unstable particles in the early Universe. We obtain the thermal invariant reaction rate using as an input the free space (vacuum) decay time and show the medium quantum effects on $\pi +\pi \leftrightarrow \rho$ reaction relaxation time. As another laboratory example we describe the $K+K\leftrightarrow \varphi$ process in thermal hadronic gas in heavy-ion collisions. A particularly interesting application of our formalism is the ${\pi }^0\leftrightarrow \gamma +\gamma$ process in the early Universe. We also explore the physics of ${\pi }^{\pm }$ and ${\mu }^{\pm }$ freeze-out in the Universe.