An analysis of data on measurements of neutron lifetime is presented. The new most accurate result of the measurement of neutron lifetime [Phys. Lett. B 605, 72 (2005)] $878.5\pm 0.8$ s, differs from the world average value [Phys. Lett. B 667, 1 (2008)] $885.7\pm 0.8$ s, by 6.5 standard deviations. In this connection an analysis and Monte Carlo simulation of experiments [Phys. Lett. B 483, 15 (2000)] and [Phys. Rev. Lett. 63, 593 (1989)] is carried out. Systematic errors of about $-6$ s are found in each of the experiments. A summary table of neutron lifetime measurements after corrections and additions is given. A new world average value for neutron lifetime, $879.9\pm 0.9$ s, is presented.

T. Li et al. [Phys. Rev. C 81, 034309 (2010)] have analyzed the measured breathing-mode energies of some tin isotopes in terms of a first-order leptodermous expansion and found the value of $-550\pm 100$ MeV for the symmetry-incompressibility coefficient $K_{\tau }$. Removing an approximation that they made, we find that the first-order estimate of $K_{\tau }$ shifts to $-661\pm 144$ MeV. However, taking into account higher-order terms in the leptodermous expansion shows that the data are compatible with the significantly lower magnitudes indicated by both another experiment and some theoretical estimates. In particular, there does not appear to be any conflict between the breathing-mode data and a value of $K_{\tau }$ consistent with most Skyrme forces.

Experimental elastic-scattering angular distributions for deuteron interaction with ${}^{63}\mathrm{Cu}$ and ${}^{93}\mathrm{Nb}$ targets are compared with calculations performed within the continuum-discretized coupled-channels (CDCC) method, in which coupling to breakup channels is explicitly taken into account. The calculated elastic breakup cross sections are compared with the predictions of an empirical parametrization for a wide range of deuteron incident energies. The good agreement between the calculations and the systematics at the energies where data are available indicates that the CDCC method permits a useful assessment of empirical parametrizations and provides useful guidance for the extrapolation of these parametrizations beyond the energies formerly considered.

A theoretical analysis of experimental results [Phys. Rev. C 80, 064608 (2009)] for isomeric ratios of ${}^{206}\mathrm{Hg}$ residues, following direct two-proton knockout from ${}^{208}\mathrm{Pb}$, is extended to consider their dependence on the longitudinal momentum of the residues. Despite the significant degree of experimental (thick target) momentum broadening, the isomeric ratio retains a significant sensitivity to this momentum. The measured distribution is well reproduced by calculations that assume the direct two-proton removal mechanism. Adjustments to the isomeric residue momentum distribution due to possible additional (unobserved) prompt feeding of the $5^{-}$ isomeric state are also discussed.

The ${}^{17}\mathrm{O}$($p,\alpha$)${}^{14}\mathrm{N}$ reaction is of fundamental relevance in several astrophysical scenarios, such as novae, asymptotic giant branch nucleosynthesis, and $\gamma$-ray astronomy. We report on the indirect measurement of the ${}^{17}\mathrm{O}$($p,\alpha$)${}^{14}\mathrm{N}$ reaction bare-nucleus cross section in the low-energy region. In particular, the two resonances at $E_R^{\mathrm{c}.\mathrm{m}.}=65$ keV and $E_R^{\mathrm{c}.\mathrm{m}.}=183$ keV, which dominate the reaction rate inside the Gamow window, have been observed, and the strength of the 65 keV resonance has been deduced. The reaction rate determination and the comparison with the results of the previous measurements are also discussed.

A high-resolution measurement of the neutron-induced fission cross section of ${}^{234}\mathrm{U}$ and ${}^{237}\mathrm{Np}$ has been performed at the CERN Neutron Time-of-Flight facility. The cross sections have been determined in a wide energy range from 1 eV to 1 GeV using the evaluated ${}^{235}\mathrm{U}$ cross section as reference. In these measurements the energy determination for the ${}^{234}\mathrm{U}$ resonances could be improved, whereas previous discrepancies for the ${}^{237}\mathrm{Np}$ resonances were confirmed. New cross-section data are provided for high neutron energies that go beyond the limits of prior evaluations, obtaining important differences in the case of ${}^{237}\mathrm{Np}$.

A thermodynamic $T$-matrix approach for elastic two-body interactions is employed to calculate spectral functions of open and hidden heavy-quark systems in the quark-gluon plasma. This enables the evaluation of quarkonium bound-state properties and heavy-quark diffusion on a common basis and thus to obtain mutual constraints. The two-body interaction kernel is approximated within a potential picture for spacelike momentum transfers. An effective field-theoretical model combining color-Coulomb and confining terms is implemented with relativistic corrections and for different color channels. Four pertinent model parameters, characterizing the coupling strengths and screening, are adjusted to reproduce the color-average heavy-quark free energy as computed in thermal lattice QCD. The approach is tested against vacuum spectroscopy in the open ($D$, $B$) and hidden ($\Psi$ and $\Upsilon$) flavor sectors, as well as in the high-energy limit of elastic perturbative QCD scattering. Theoretical uncertainties in the static reduction scheme of the four-dimensional Bethe-Salpeter equation are elucidated. The quarkonium spectral functions are used to calculate Euclidean correlators which are discussed in light of lattice QCD results, while heavy-quark relaxation rates and diffusion coefficients are extracted utilizing a Fokker-Planck equation.

The Chew-Mandelstam (CM) parametrization, which has been used extensively in the two-body hadronic sector, is generalized in this exploratory paper to the electromagnetic sector by simultaneous fits to the $\pi$- and $\eta$-photoproduction $S$-wave multipole amplitudes for center-of-mass energies from the pion threshold through 1.61 GeV. We review the CM parametrization in detail to clarify the theoretical content of the said hadronic amplitude analysis and to place the proposed generalized said electromagnetic amplitudes in the context of earlier employed parametrized forms. The parametrization is unitary at the two-body level, which employs four hadronic channels and the $\gamma N$ electromagnetic channel. We compare the resulting fit to the maid parametrization and find qualitative agreement; although, numerically, the solution is somewhat different. Applications of the extended parametrization to global fits of the photoproduction data and to global fits of the combined hadronic and photoproduction data are discussed.

In this Rapid Communication, we report on $\alpha$-particle emission through the nuclear breakup in the reaction ${}^{40}\mathrm{Ca}$ on a ${}^{40}\mathrm{Ca}$ target at 50 A MeV. It is observed that, similar to nucleons, $\alpha$ particles can be emitted to the continuum with very specific angular distribution during the reaction. The $\alpha$-particle properties seem to be compatible with an $\alpha$ cluster in the daughter nucleus that is perturbed and is emitted by the short-range nuclear attraction of the collision partner. A time-dependent theory that describes the $\alpha$-particle wave-function evolution is able to qualitatively reproduce the observed angular distribution. This mechanism offers new possibilities for studying $\alpha$-particle properties in the nuclear medium.

Using the GXPF1A interaction for the $\mathit{pf}$ shell nuclei, we calculate energy levels and $E2$ transition rates for the semimagic nuclei ${}^{43-46}\mathrm{Ca}$ within both the exact shell-model space and a number of subspaces constructed using collective nucleon pairs. We present explicitly the overlaps between wave functions of low-lying states obtained from shell-model calculations and those obtained using truncated nucleon-pair subspaces. These examples are used as touchstones of pair approximations.

By using an exponential function to simulate the residual proton-neutron interaction between valence nucleons, we derive a new set of local mass formulas that are competitive with the Garvey-Kelson mass relations for relating neighboring nuclear masses.

Excited states in ${}^{30}\mathrm{Mg}$ have been populated to $~$$6\hslash$ and 5 MeV excitation energy with the ${}^{14}\mathrm{C}$(${}^{18}\mathrm{O}$,$2p$) reaction. Firm spin assignments for states with $J>2\hslash$ have been made in this nucleus. The level scheme is compared to shell-model calculations using the Universal $\mathit{sd}$ effective interaction and the Monte Carlo shell model method. Calculations employing a full $\mathit{sd}$ model space fail to reproduce the observed levels. The results indicate that excitations across the $N=20$ gap are required at relatively low excitation energy to achieve a description of the data. The incorporation of the $f_{7/2}$ and $p_{3/2}$ orbitals into the model space gives improved results but indicate the need for further refinement of the models to reproduce the observed spectra.

An attempt has been made to extract the evolution of radial flow from the analysis of the experimental data on electromagnetic probes measured at the energies available at the CERN Super Proton Synchrotron (SPS) and the BNL Relativistic Heavy Ion Collider (RHIC). The transverse momentum ($p_T$) spectra of photons and dileptons measured by the WA98 and NA60 Collaborations, respectively, at the SPS and the photon and dilepton spectra obtained by the PHENIX Collaboration at the RHIC have been used to constrain the theoretical models. We use the ratio of photon to dilepton spectra to extract the flow, where some model dependence is canceled out. Within the ambit of the present analysis we argue that the variation of the radial velocity with invariant mass is indicative of a phase transition from the initially produced partons to hadrons at SPS and RHIC energies.

The spinodal amplification of density fluctuations is treated perturbatively within dissipative fluid dynamics for the purpose of elucidating the prospects for this mechanism to cause a phase separation to occur during a relativistic nuclear collision. The present study includes not only viscosity but also heat conduction (whose effect on the growth rates is of comparable magnitude but opposite), as well as a gradient term in the local pressure, and the corresponding dispersion relation for collective modes in bulk matter is derived from relativistic fluid dynamics. A suitable two-phase equation of state is obtained by interpolation between a hadronic gas and a quark-gluon plasma, while the transport coefficients are approximated by simple parametrizations that are suitable at any degree of net baryon density. We calculate the degree of spinodal amplification occurring along specific dynamical phase trajectories characteristic of nuclear collision at various energies. The results bring out the important fact that the prospects for spinodal phase separation to occur can be greatly enhanced by careful tuning of the collision energy to ensure that the thermodynamic conditions associated with the maximum compression lie inside the region of spinodal instability.

Cluster-core potentials derived microscopically or phenomenologically each have some desirable features. We combine these features in an analysis of the properties of ${}^{212}\mathrm{Po}$ treated as an $\alpha$-${}^{208}\mathrm{Pb}$ system.

We derive a compact, semialgebraic expression for the cold-quark-matter equation of state (EoS) in a covariant model that exhibits coincident deconfinement and chiral symmetry restoring transitions in medium. In doing so we obtain algebraic expressions for the number- and scalar-density distributions in both the confining Nambu and the deconfined Wigner phases and the vacuum-pressure difference between these phases, which defines a bag constant. Our qualitative study illustrates that a confining interaction can materially alter distribution functions from those of a Fermi gas and impact significantly on a system’s thermodynamic properties, possibilities that are apparent in the EoS.

High-spin states in ${}^{125}\mathrm{I}$ were populated using the reaction ${}^{82}\mathrm{Se}$(${}^{48}\mathrm{Ca},p4n$) at a beam energy of 200 MeV and $\gamma$-ray coincidence events were acquired with the Gammasphere spectrometer. The level scheme of ${}^{125}\mathrm{I}$ was extended considerably. In particular, maximally aligned states involving all eleven particles outside the ${}^{114}\mathrm{Sn}$ core were observed. Comparison with cranked Nilsson-Strutinsky calculations suggests that three of these states are the final $I_{\max }$ states in terminating bands with all spin vectors aligned along a common axis. In two of these, one spin vector is antialigned and points in the opposite direction. In one of the states two spin vectors are antialigned. This is the first observation of a state with such a structure.

The role of superfluidity in incompressibility and in symmetry energy is studied in nuclear matter and finite nuclei. Several pairing interactions are used: surface, mixed, and isovector dependent. Pairing has a small effect on the nuclear matter incompressibility at saturation density, but the effects are significant at lower densities. The pairing effect on the centroid energy of the isoscalar giant monopole resonance (GMR) is also evaluated for Pb and Sn isotopes by using a microscopic constrained-HFB approach and is found to change at most by 10% the nucleus incompressibility $K_A$. It is shown by using the local density approximation that most of the pairing effect on the GMR centroid comes from the low-density nuclear surface.

The effect of different isospin-dependent cross-sections on directed flow is studied for a variety of systems (for which experimental balance energies are available) using an isospin-dependent quantum molecular dynamic (IQMD) model. We show that balance energies are sensitive toward isospin-dependent cross sections for light systems, while nearly no effect exists for heavier nuclei. A reduced cross-section $\sigma =0.9{\sigma }_{\mathrm{NN}}$ with stiff equation of state is able to explain experimental balance energies in most of systems. A power law behavior is also given for the mass dependence of balance energy, which also follows the $N/Z$ dependence.

The synthesis of isotopes of the element hassium was studied using the reaction ${}^{34}\mathrm{S}+{}^{238}\mathrm{U}\to {}^{272}\mathrm{Hs}{}^{*}$. At a kinetic energy of $163.0$ MeV in the center-of-mass system we observed one $\alpha$-decay chain starting at the isotope ${}^{267}\mathrm{Hs}$. The cross section was $1.8_{-1.5}^{+4.2}$ pb. At $152.0$ MeV one decay of the new isotope ${}^{268}\mathrm{Hs}$ was observed. It decays with a half-life of $0.{38}_{-0.17}^{+1.8}$ s by $9479\pm 16$ keV $\alpha$-particle emission. Spontaneous fission of the daughter nucleus ${}^{264}\mathrm{Sg}$ was confirmed. The measured cross section was $0.{54}_{-0.45}^{+1.3}$ pb. In-beam measurements of fission-fragment mass distributions were performed to obtain information on the fusion probability at various orientations of the deformed target nucleus. The distributions changed from symmetry to asymmetry when the beam energy was changed from above-barrier to sub-barrier values, indicating orientation effects on fusion and/or quasifission. It was found that the distribution of symmetric mass fragments originates not only from fusion-fission, but has a strong component from quasifission. The result was supported by a calculation based on a dynamical description using the Langevin equation, in which the mass distributions for fusion-fission and quasifission fragments were separately determined.