Existing ${}^{10}$Be($d$,$t$)${}^9$Be neutron pickup data are analyzed using the same bound-state form factors for the ${\langle }^{10}\mathrm{Be}{|}^9\mathrm{Be}+n\rangle$ overlap as in a recent analysis of single-neutron knockout [Grinyer et al.,  Phys. Rev. Lett. 106, 162502 (2011)]. While the knockout data were well described by a bound-state form factor calculated using the variational Monte Carlo (VMC) technique, including an appropriate neutron binding potential, the ${}^{10}$Be($d$,$t$)${}^9$Be pickup data are significantly overpredicted using this form factor. In addition, the no-core shell model (NCSM) and VMC form factors yield the same calculated pickup cross sections whereas the knockout results using these form factors differed by 20$\%$. We explore possible sources of ambiguity in the pickup calculations that affect our ability to compare the absolute magnitudes in cross sections between these two very different reactions.

We study the influence of a temperature-dependent shear viscosity over entropy density ratio $\eta /s$, different shear relaxation times ${\tau }_{\pi }$, as well as different initial conditions on the transverse momentum spectra of charged hadrons and identified particles. We investigate the azimuthal flow asymmetries as a function of both collision energy and centrality. The elliptic flow coefficient turns out to be dominated by the hadronic viscosity at RHIC energies. Only at higher collision energies the impact of the viscosity in the QGP phase is visible in the flow asymmetries. Nevertheless, the shear viscosity near the QCD transition region has the largest impact on the collective flow of the system. We also find that the centrality dependence of the elliptic flow is sensitive to the temperature dependence of $\eta /s$.

We present a model for describing nuclear matter at finite density based on quarks interacting with chiral fields $\sigma$ and $\pi$ and with vector mesons introduced as massive gauge fields. The chiral Lagrangian includes a logarithmic potential, associated with the breaking of scale invariance. We provide results for the soliton in vacuum and at finite density, using the Wigner-Seitz approximation. We show that the model can reach higher densities with respect to the linear $\sigma$ model, and that the introduction of vector mesons allows us to obtain saturation.

Following neutron knockout from an ${}^{13}$O beam, ${}^{12}$O fragments were created and the three decay products following two-proton decay were detected. A new ground-state mass was determined by the invariant mass method implying a decay kinetic energy of 1.638(24) MeV, and the width was found to be less than 72 keV. The latter is inconsistent with previous measurements with lower experimental resolutions but consistent with theoretical estimates. The isobaric analog of ${}^{12}$O in ${}^{12}$N was produced from proton knockout reactions with the same beam and decayed by two-proton emission to the isobaric analog state in ${}^{10}$B with a decay kinetic energy of 1.165(29) MeV. It represents only the second case of an analog state where two-proton decay is the only isospin- and energy-conserving particle decay mode. With our measurements of the mass excesses of ${}^{12}$O and its analog, the quadratic form of the isobaric multiplet mass equation was found to fit the $A=12$ quintet and any deviations are less than the magnitude found for the $A=8$ quintet and $A=7$ and 9 quartets.

Intermediate-energy Coulomb excitation measurements were performed on the neutron-rich isotopes ${}^{58,60,62}$Cr. The electric quadrupole excitation strengths, $B$($E$2; 0${}_1^{+}\to 2_1^{+}$), of ${}^{60,62}$Cr are determined for the first time. The results quantify the trend of increasing quadrupole collectivity in the Cr isotopes approaching neutron number $N=40$. The results are confronted with large-scale shell-model calculations in the $fpgd$ shell using the state-of-the-art LNPS effective interaction. Different sets of effective charges are discussed that provide an improved and robust description of the $B\left(E2\right)$ values of the neutron-rich Fe and Cr isotopes in this region of rapid shell evolution. The ratio of the neutron and proton transition matrix elements, $|M_n/M_p|$, is proposed as an effective tool to discriminate between the various choices of effective charges.

Nuclear interactions evolved via renormalization group methods to lower resolution become increasingly nonlocal (off-diagonal in coordinate space) as they are softened. This inhibits both the development of intuition about the interactions and their use with some methods for solving the quantum many-body problem. By applying “local projections”, a softened interaction can be reduced to a local effective interaction plus a nonlocal residual interaction. At the two-body level, a local projection after similarity renormalization group (SRG) evolution manifests the elimination of short-range repulsive cores and the flow toward universal low-momentum interactions. The SRG residual interaction is found to be relatively weak at low energy, which motivates a perturbative treatment.

A model of the bremsstrahlung emission which accompanies proton decay and collisions of protons off nuclei in the low- to intermediate-energy region has been developed. This model includes spin formalism, a potential approach for describing the interaction between protons and nuclei, and an emission that includes a component of the magnetic emission (defined on the basis of the Pauli equation). For the problem of bremsstrahlung during proton decay the role of magnetic emission is studied by using such a model. For the ${}^{146}\mathrm{Tm}$ nucleus the following has been studied: (1) How much does the magnetic emission change the full bremsstrahlung spectrum? (2) At which angle is the magnetic emission the most intensive relative to the electric emission? (3) Is there some spatial region where the magnetic emission increases strongly relative to the electric emission? (4) How intensive is the magnetic emission in the tunneling region? (5) Which is the maximal probability? Which value does it equal to at the zero-energy limit of the emitted photons? It is demonstrated that the model is able to describe well enough experimental data of bremsstrahlung emission which accompanies collisions of protons off ${}^9\mathrm{C}$, ${}^{64}\mathrm{Cu},$ and ${}^{107}\mathrm{Ag}$ nuclei at an incident energy of $T_{\mathrm{lab}}=72$ MeV (at a photon energy up to 60 MeV) and off ${}^9\mathrm{Be}$, ${}^{12}\mathrm{C},$ and ${}^{208}\mathrm{Pb}$ nuclei at an incident energy of $T_{\mathrm{lab}}=140$ MeV (at a photon energy up to 120 MeV).

The quark-gluon plasma is considered to behave as a relativistic viscous fluid in high-energy heavy-ion collisions. In this study, I develop and estimate a second-order dissipative hydrodynamic model at finite baryon density with effects of baryon dissipation together with those of shear and bulk viscosities. It is found that the hydrodynamic evolution effectively reduces baryon stopping, suggesting that the collisions are less transparent at the initial stage. Also the net baryon distribution is found to be sensitive to baryon dissipation as well as to viscosities. The results indicate that dissipative hydrodynamic modeling would be important for understanding the unique properties of a hot medium even in high-energy collisions.

A model is proposed to describe nucleons ejected from a nucleus as a result of two-body-current neutrino interactions. The model can be easily implemented in Monte Carlo neutrino event generators. Various possibilities to measure the two-body-current contribution are discussed. The model can help identify genuine charge current quasielastic events and allow for a better determination of the systematic error on neutrino energy reconstruction in neutrino oscillation experiments.

Background: Electron-capture reaction rates on medium-heavy nuclei are an important ingredient for modeling the late evolution of stars that become core-collapse or thermonuclear supernovae. The estimation of these rates requires the knowledge of Gamow-Teller strength distributions in the ${\beta }^{+}$ direction. Astrophysical models rely on electron-capture rate tables largely based on theoretical models, which must be validated and tested against experimental results.

Purpose: This paper presents a systematic evaluation of the ability of theoretical models to reproduce experimental Gamow-Teller transition strength distributions measured via ($n$,$p$)-type charge-exchange reactions at intermediate beam energies. The focus is on transitions from stable nuclei in the $pf$ shell ($45\le A\le 64$). In addition, the impact of deviations between experimental and theoretical Gamow-Teller strength distributions on derived stellar electron-capture rates is investigated.

Method: Data on Gamow-Teller transitions from 13 nuclei in the $pf$ shell measured via charge-exchange reactions and supplemented with results from $\beta$-decay experiments where available, were compiled and compared with strength distributions calculated in shell models (using the GXPF1a and KB3G effective interactions) and quasiparticle random-phase approximation (QRPA) using ground-state deformation parameters and masses from the finite-range droplet model. Electron-capture rates at relevant stellar temperatures and densities were derived for all distributions and compared.

Results: With few exceptions, shell-model calculations in the $pf$ model space with the KB3G and GXPF1a interactions qualitatively reproduce experimental Gamow-Teller strength distributions of 13 stable isotopes with $45\le A\le 64$. Results from QRPA calculations exhibit much larger deviations from the data and overestimate the total experimental Gamow-Teller strengths. For stellar densities in excess of ${10}^7$ g/cm${}^3$, ground-state electron-capture rates derived from the shell-model calculations using the KB3G (GXPF1a) interaction deviate on average less than 47$\%$ (31$\%$) from those derived from experimental data for which the location of daughter states at low excitation energies are well established. For electron-capture rates derived from Gamow-Teller strengths calculated in QRPA, the deviations are much larger, especially at low stellar densities.

Conclusions: Based on the limited set of test cases available for nuclei in the $pf$ shell, shell-models using the GXPF1a and KB3G interactions can be used to estimate electron-capture rates for astrophysical purposes with relatively good accuracy. Measures of the uncertainties in these rates can serve as input for sensitivity studies in stellar evolution models. Ground-state electron-capture rates based on the QRPA formalism discussed in the paper exhibit much larger deviations than those based on the shell-model calculations and should be used with caution, especially at low stellar densities.

The National Ignition Facility (NIF) is designed to drive deuterium-tritium (DT) inertial confinement fusion targets to ignition using indirect radiation from laser energy captured in a hohlraum. The projected yields at NIF suggest that interactions of neutrons with the hohlraum can directly probe the neutron spectrum. Different physical parameters of the burning capsule can be probed by different neutron reactions. We suggest a variety of neutron reactions on the gold and uranium present in National Ignition Campaign hohlraums that will be useful for both neutron diagnostics and dosimetry at the NIF. The radiochemical daughter products may then be used to infer the neutron spectrum from the capsule. The downscattered neutrons may be studied by the $(n,\gamma )$ and $(n,n^{\prime })$ reactions to infer the areal density of the capsule. The 14 MeV neutron fluence may be measured by $(n,2n)$ daughter products for comparison to neutron spectrometer data. The hydrodynamical mix in the capsule can be studied with RIF neutrons, which are probed by $(n,3n)$ reactions.

Virtual Compton scattering (VCS) on the proton has been studied at the Jefferson Laboratory using the exclusive photon electroproduction reaction $ep\to ep\gamma$. This paper gives a detailed account of the analysis which has led to the determination of the structure functions $P_{LL}-P_{TT}/\epsilon$ and $P_{LT}$ and the electric and magnetic generalized polarizabilities (GPs) ${\alpha }_E\left(Q^2\right)$ and ${\beta }_M\left(Q^2\right)$ at values of the four-momentum transfer squared $Q^2=0.92$ and 1.76 GeV${}^2$. These data, together with the results of VCS experiments at lower momenta, help building a coherent picture of the electric and magnetic GPs of the proton over the full measured $Q^2$ range and point to their nontrivial behavior.

Differential measurements of charged particle azimuthal anisotropy are presented for lead-lead collisions at $\sqrt{s_{NN}}=2.76$ TeV with the ATLAS detector at the LHC, based on an integrated luminosity of approximately 8 $\mu {\mathrm{b}}^{-1}$. This anisotropy is characterized via a Fourier expansion of the distribution of charged particles in azimuthal angle relative to the reaction plane, with the coefficients $v_n$ denoting the magnitude of the anisotropy. Significant $v_2$–$v_6$ values are obtained as a function of transverse momentum ($0.5<p_{\mathrm{T}}<20$ GeV), pseudorapidity ($\left|\eta \right|<2.5$), and centrality using an event plane method. The $v_n$ values for $n\ge 3$ are found to vary weakly with both $\eta$ and centrality, and their $p_{\mathrm{T}}$ dependencies are found to follow an approximate scaling relation, $v_n^{1/n}\left(p_{\mathrm{T}}\right)\propto v_2^{1/2}\left(p_{\mathrm{T}}\right)$, except in the top 5$\%$ most central collisions. A Fourier analysis of the charged particle pair distribution in relative azimuthal angle ($\Delta \phi ={\phi }_{\mathrm{a}}-{\phi }_{\mathrm{b}}$) is performed to extract the coefficients $v_{n,n}=\langle \cos n\Delta \phi \rangle$. For pairs of charged particles with a large pseudorapidity gap ($|\Delta \eta ={\eta }_{\mathrm{a}}-{\eta }_{\mathrm{b}}|>2$) and one particle with $p_{\mathrm{T}}<3$ GeV, the $v_{2,2}$–$v_{6,6}$ values are found to factorize as $v_{n,n}(p_{\mathrm{T}}^{\mathrm{a}},p_{\mathrm{T}}^{\mathrm{b}})\approx v_n\left(p_{\mathrm{T}}^{\mathrm{a}}\right)v_n\left(p_{\mathrm{T}}^{\mathrm{b}}\right)$ in central and midcentral events. Such factorization suggests that these values of $v_{2,2}$–$v_{6,6}$ are primarily attributable to the response of the created matter to the fluctuations in the geometry of the initial state. A detailed study shows that the $v_{1,1}(p_{\mathrm{T}}^{\mathrm{a}},p_{\mathrm{T}}^{\mathrm{b}})$ data are consistent with the combined contributions from a rapidity-even $v_1$ and global momentum conservation. A two-component fit is used to extract the $v_1$ contribution. The extracted $v_1$ is observed to cross zero at $p_{\mathrm{T}}\approx 1.0$ GeV, reaches a maximum at 4–5 GeV with a value comparable to that for $v_3$, and decreases at higher $p_{\mathrm{T}}$.

In this paper we study the photoproduction of scalar mesons in the intermediate energies, considering distinct mixing scenarios in the description of meson physical states. The differential and integrated total cross sections are computed for the cases of the mesons $a_0\left(980\right)$, $f_0\left(1500\right)$, and $f_0\left(1710\right)$, focusing on the GlueX energy regime with photon energy $E_{\gamma }=9$ GeV. Our results indicate that light-quark scalar meson photoproduction is well suited for studying hybrid mesons' structures.

We consider the astrophysical reaction rates for radiative neutron capture reactions ($n,\gamma$) in the crust of a neutron star. The presence of degenerate neutrons at high densities (mainly in the inner crust) can drastically affect the reaction rates. Standard rates assuming a Maxwell-Boltzmann distribution for neutrons can underestimate the rates by several orders of magnitude. We derive simple analytical expressions for reaction rates at a variety of conditions with account for neutron degeneracy. We also discuss the plasma effects on the outgoing radiative transition channel in neutron radiative capture reactions and show that these effects can also increase the reaction rates by a few orders of magnitude. In addition, using detailed balance, we analyze the effects of neutron degeneracy and plasma physics on reverse ($\gamma ,n$) photodisintegration. We discuss the dependence of the reaction rates on temperature and neutron chemical potential and outline the efficiency of these reactions in the neutron star crust.

In this paper we study the one- and two-nucleon separation energies ($S_n$, $S_p$, $S_{2n}$, and $S_{2p}$) by using the Atomic-Mass-Evaluation-2011 Preview. We show the linear dependence of separation energies, previously investigated for $S_n$ and $S_p$ of even-even nuclei, in terms of $\alpha N_p+\beta N_n$ ($N_p$ and $N_n$ is the valence proton number and valence neutron number, respectively, with respect to the nearest magic closure), hold in a broader sense. It is applicable equally well to odd-mass and odd-odd nuclei. New odd-even staggerings are found for $S_n$ and $S_p$, and are discussed by using the pairing interaction and the symmetry energy. Predictive power of these simple relations is discussed.

A realistic density-dependent nucleon-nucleon ($NN$) interaction with a finite-range exchange part which produces the nuclear matter saturation curve and the energy dependence of the nucleon-nucleus optical potential model is used to calculate the preformation probability, $S_{\alpha }$, of $\alpha$ decay from Po isotopes to superheavy nuclei. The variation of $S_{\alpha }$ with the neutron number for the isotopes of Po, Rn, Ra, Th, and U elements is studied below and above the magic neutron number $N=126$. We found a strong correlation between the behavior of $S_{\alpha }$ and the energy levels of the parent nucleus at and just below the Fermi level. $S_{\alpha }$ has a regular behavior with the neutron number if the neutron pair of $\alpha$ particles, emitted from adjacent isotopes, comes from the same energy level or from a group of levels, assuming that the order of levels in this group is not changed. Irregular behavior of $S_{\alpha }$ with the neutron number occurs if the levels of the adjacent isotopes change or holes are present in lower levels.

We present a combined analysis of the available isotope-shift data from the optical spectra of Ra atoms and Ra${}^{+}$ ions. Atomic structure calculations of the field-shift and specific mass-shift constants of the low-lying levels in Ra${}^{+}$ are used. The nuclear radial differences $\delta \langle r^2\rangle$ for the radium isotopes are derived and compared to previous analyses and nuclear models. We discuss the relevance of our results to measurements of atomic parity violation in a chain of Ra${}^{+}$ isotopes.

High-precision mass measurements of neutron-rich ${}^{57-66}$Mn and ${}^{61-63}$Fe isotopes are reported. The new mass surface shows no shell closure at $N=40$. In contrast, there is an increase of the two-neutron separation energy at $N=38$. This behavior is consistent with the onset of collectivity due to the occupation of intruder states from higher orbits, in analogy with the well known “island of inversion” around $N=20$. Our results indicate that the neutron-rich Mn isotopes, starting from ${}^{63}$Mn, are most likely within the new island of inversion. From the new mass surface, we evaluate the empirical proton-neutron interaction and the pairing gap, both playing a significant role in the structural changes in this region.