The ${}^{33}$S($p,\gamma$)${}^{34}$Cl reaction is important for constraining predictions of certain isotopic abundances in oxygen-neon novae. Models currently predict as much as 150 times the solar abundance of ${}^{33}$S in oxygen-neon nova ejecta. This overproduction factor may vary by orders of magnitude due to uncertainties in the ${}^{33}$S($p,\gamma$)${}^{34}$Cl reaction rate at nova peak temperatures. Depending on this rate, ${}^{33}$S could potentially be used as a diagnostic tool for classifying certain types of presolar grains. Better knowledge of the ${}^{33}$S($p,\gamma$)${}^{34}$Cl rate would also aid in interpreting nova observations over the S-Ca mass region and contribute to the firm establishment of the maximum endpoint of nova nucleosynthesis. Additionally, the total S elemental abundance which is affected by this reaction has been proposed as a thermometer to study the peak temperatures of novae. Previously, the ${}^{33}$S($p,\gamma$)${}^{34}$Cl reaction rate had only been studied directly down to resonance energies of 432 keV. However, for nova peak temperatures of $0.2–0.4$ GK there are seven known states in ${}^{34}$Cl both below the 432-keV resonance and within the Gamow window that could play a dominant role. Direct measurements of the resonance strengths of these states were performed using the DRAGON (Detector of Recoils And Gammas of Nuclear reactions) recoil separator at TRIUMF. Additionally two new states within this energy region are reported. Several hydrodynamic simulations have been performed, using all available experimental information for the ${}^{33}$S($p,\gamma$)${}^{34}$Cl rate, to explore the impact of the remaining uncertainty in this rate on nucleosynthesis in nova explosions. These calculations give a range of $\approx$20–150 for the expected ${}^{33}$S overproduction factor, and a range of $\approx$100–450 for the ${}^{32}$S/${}^{33}$S ratio expected in ONe novae.

We compare the results obtained in the framework of the quasiparticle random-phase approximation on top of a Hartree-Fock-Bogoliubov with the most recent experiments on giant monopole resonances in Pb, Sn, Zr, Sm, Mo, and Cd. Our calculations are fully self-consistent and the density dependence of pairing interactions is, for the first time in this framework, properly taken into account. In the particle-hole (ph) channel we employ different Skyrme functionals (SLy5, SkM* and Skxs20) while in the particle-particle (pp) channel we make use of density-dependent contact interactions. We introduce in the pp channel the recently proposed contact interactions which take into account the neutron-proton asymmetry. We find that no single parametrization is able to reproduce with sufficient accuracy all the nuclei. Since about two-thirds of the nuclei under investigation are better explained with a soft parametrization, this tends to suggest that the currently accepted picture for the incompressibility might require modifications.

The cluster decays ${}^{228}\text{Th}\to {}^{208}\text{Pb}+{}^{20}\text{O}$, ${}^{232}\text{U}\to {}^{208}\text{Pb}+{}^{24}\text{Ne}$, ${}^{236}\text{Pu}\to {}^{208}\text{Pb}+{}^{28}\text{Mg}$, and ${}^{242}\text{Cm}\to {}^{208}\text{Pb}+{}^{34}\text{Si}$ are considered in the framework of the multidimensional cluster-preformation model. The macroscopic potential-energy surface related to the interaction between the cluster and the residue nucleus is evaluated in the framework of the nonlocal ${\hslash }^4$ extended Thomas-Fermi approach with Skyrme and Coulomb forces. The shell correction to the macroscopic potential energy is also taken into account. The dynamical surface deformations of both the cluster and the residue nucleus are taken into consideration at the barrier penetration path. The heights of saddle points related to deformed nuclear shapes are lower than the barrier height between the spherical cluster and residue nuclei; therefore the dynamical deformations of nuclei increase the barrier penetrability and reduce the half-life of cluster decay. The shell-correction contribution into the potential energy between cluster and residue nucleus is important for both the potential landscape and the half-life evaluation. The experimental values of cluster-decay half-lives are well reproduced in the model.

We report the first observation of the line shape of the $\Lambda \left(1405\right)$ from electroproduction, and show that it is not a simple Breit-Wigner resonance. Electroproduction of $K^{+}\Lambda \left(1405\right)$ off the proton was studied by using data from CLAS at Jefferson Lab in the range $1.0<Q^2<3.0$ (GeV/$c$)${}^2$. The analysis utilized the decay channels ${\Sigma }^{+}{\pi }^{-}$ of the $\Lambda \left(1405\right)$ and $p{\pi }^0$ of the ${\Sigma }^{+}$. Neither the standard Particle Data Group resonance parameters, nor free parameters fitting to a single Breit-Wigner resonance represent the line shape. In our fits, the line shape corresponds approximately to predictions of a two-pole meson-baryon picture of the $\Lambda \left(1405\right)$, with a lower mass pole near 1368 MeV/$c^2$ and a higher mass pole near 1423 MeV/$c^2$. Furthermore, with increasing photon virtuality the mass distribution shifts toward the higher mass pole.

The low-spin level scheme of ${}^{68}$Ni was investigated following two-neutron-knockout and multinucleon-transfer reactions. The energy of the first excited state was determined to be $E_x\left(0_2^{+}\right)=1603.5\left(3\right)$ keV. Relative $B\left(E2\right)$ transition probabilities were deduced and compared with shell-model calculations using several modern effective interactions. Theory reproduces the data well, but indicates substantial mixing of multi-particle, multi-hole configurations for the lowest observed $0^{+}$ and $2^{+}$ states.

We analyze the multiplicity correlations between distant forward and backward rapidity regions in relativistic heavy-ion collisions in a superposition framework, where the particle production occurs through independent emission from correlated sources. This in principle allows for inferring information on the long-range forward-backward correlations of the sources in the earliest phase of the collision, based solely on the experimental information on the statistical features of the observed particle distributions. Our three-stage study incorporates the fluctuations of parton production in the early phase, the effect of intermediate hydrodynamic evolution, as well as fluctuations in the production of particles at freeze-out. We investigate the dependence of the results on the features of the overlaid distributions and hydrodynamics, as well as the centrality dependence. We analyze the existing data from the STAR Collaboration. Predictions for the forward-backward multiplicity correlations in Pb+Pb collisions to be analyzed at the Large Hadron Collider are also made.

Limits on the tensor couplings generating a Fierz interference term $b$ in mixed Gamow-Teller Fermi decays can be derived by combining data from measurements of angular correlation parameters in neutron decay, the neutron lifetime, and $G_{\mathrm{V}}=G_{\mathrm{F}}{V}_{ud}$ as extracted from measurements of the $\mathcal{F}t$ values from the $0^{+}\to 0^{+}$ superallowed decay data set. These limits are derived by comparing the neutron $\beta$-decay rate as predicted in the standard model with the measured decay rate while allowing for the existence of beyond the standard model (BSM) couplings. We analyze limits derived from the electron-neutrino asymmetry $a$, or the beta asymmetry $A$, finding that the most stringent limits for $C_{\mathrm{T}}/C_{\mathrm{A}}$ under the assumption of no right-handed neutrinos is $-0.0026<C_{\mathrm{T}}/C_{\mathrm{A}}<0.0024$ (95% C.L.) for the two most recent values of $A$. The derived limits on scalar and tensor couplings have the useful property that they are independent of BSM extensions with vector or axial-vector symmetry to first order.

States in ${}^{18}$N have been populated in the neutron-adding $(d,p)$ reaction on the short-lived ${}^{17}$N beam. Previously observed levels, found in this work at excitation energies of 0.12(1) MeV and 0.74(1) MeV, have been identified as those expected from a proton $0p_{1/2}$ hole coupled to the ${}^{19}$O $5/2^{+}$ ground state. A new state at 1.17(2) MeV is consistent with the coupling of the $1/2^{-}$ proton-hole state to the excited $1/2^{+}$ state in ${}^{19}$O. Orbital angular momentum assignments and spectroscopic factors were determined from the measured angular distributions through a distorted wave Born approximation analysis. Systematics for the ${\left(0d_{5/2}1s_{1/2}\right)}^3$ neutron configurations in the $N=11$ isotones, ${}^{17}$C, ${}^{18}$N, and ${}^{19}$O are discussed and comparisons to $p$-$sd$ shell-model calculations are made.

No-core Gamow shell model (NCGSM) is applied to study selected well-bound and unbound states of helium isotopes. This model is formulated on the complex energy plane and, by using a complete Berggren ensemble, treats bound, resonant, and scattering states on equal footing. We use the density matrix renormalization group method to solve the many-body Schrödinger equation. To test the validity of our approach, we benchmarked the NCGSM results against Faddeev and Faddeev-Yakubovsky exact calculations for ${}^3$H and ${}^4$He nuclei. We also performed ab initio NCGSM calculations for the unstable nucleus ${}^5$He and determined the ground-state energy and decay width, starting from a realistic N${}^3$LO chiral interaction.

We present a model to explain the bottomonium suppression in Pb$+$Pb collisions at midrapidity obtained from Large Hadron Collider (LHC) energy, $\sqrt{s_{NN}}=2.76$ TeV. The model consists of two decoupled mechanisms, namely, color screening during bottomonium production followed by gluon induced dissociation along with collisional damping. The quasiparticle model (QPM) is used as equation of state (EOS) for the quark-gluon plasma (QGP) medium. The feed-down from higher ${\rm Y}$ states, such as ${\rm Y}\left(1P\right)$, ${\rm Y}\left(2S\right)$, and ${\rm Y}\left(2P\right)$, dilated formation times for bottomonium states, and viscous effect of the QGP medium are other ingredients included in the current formulation. We further assume that the QGP is expanding according to ($1+1$)-dimensional Bjorken's boost invariant scaling law. The net suppression (in terms of $p_T$ integrated survival probability) for bottomonium states at midrapidity is obtained as a function of centrality, and the result is then compared both quantitatively and qualitatively with the recent LHC experimental data in the midrapidity region recently published by the CMS Collaboration. We find that the current model, based on Debye color screening plus gluonic dissociation along with collisional damping, better describes the centrality dependence of bottomonium suppression at LHC energy as compared to the color screening model alone.

This publication describes the methods used to measure the centrality of inelastic Pb-Pb collisions at a center-of-mass energy of 2.76 TeV per colliding nucleon pair with ALICE. The centrality is a key parameter in the study of the properties of QCD matter at extreme temperature and energy density, because it is directly related to the initial overlap region of the colliding nuclei. Geometrical properties of the collision, such as the number of participating nucleons and the number of binary nucleon-nucleon collisions, are deduced from a Glauber model with a sharp impact parameter selection and shown to be consistent with those extracted from the data. The centrality determination provides a tool to compare ALICE measurements with those of other experiments and with theoretical calculations.

In this paper measurements are presented of ${\pi }^{\pm }$, $K^{\pm }$, $p$, and $\overline{p}$ production at midrapidity ($\left|y\right|<0.5$), in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV as a function of centrality. The measurement covers the transverse-momentum ($p_T$) range from 100, 200, and 300 MeV/$c$ up to 3, 3, and 4.6 GeV/$c$ for $\pi$, $K$, and $p$, respectively. The measured $p_T$ distributions and yields are compared to expectations based on hydrodynamic, thermal and recombination models. The spectral shapes of central collisions show a stronger radial flow than measured at lower energies, which can be described in hydrodynamic models. In peripheral collisions, the $p_T$ distributions are not well reproduced by hydrodynamic models. Ratios of integrated particle yields are found to be nearly independent of centrality. The yield of protons normalized to pions is a factor $\sim$1.5 lower than the expectation from thermal models.

We derive relativistic viscous hydrodynamic equations invoking the generalized second law of thermodynamics for two different forms of the nonequilibrium single-particle distribution function. We find that the relaxation times in these two derivations are identical for shear viscosity but different for bulk viscosity. These equations are used to study thermal dilepton and hadron spectra within longitudinal scaling expansion of the matter formed in relativistic heavy-ion collisions. For consistency, the same nonequilibrium distribution function is used in the particle production prescription as in the derivation of the viscous evolution equations. Appreciable differences are found in the particle production rates corresponding to the two nonequilibrium distribution functions. We emphasize that an inconsistent treatment of the nonequilibrium effects influences the particle production significantly, which may affect the extraction of transport properties of quark-gluon plasma.

Neutron-proton elliptic flow difference and ratio have been shown to be promising observables in the attempt to constrain the density dependence of the symmetry energy above the saturation point from heavy-ion collision data. Their dependence on model parameters such as microscopic nucleon-nucleon cross sections, compressibility of nuclear matter, optical potential, and symmetry energy parametrization is thoroughly studied. By using a parametrization of the symmetry energy derived from the momentum-dependent Gogny force in conjunction with the Tübingen quantum molecular dynamics (QMD) model and comparing the results with the experimental FOPI-LAND data for ${}^{197}$Au +${}^{197}$Au collisions at 400 MeV/nucleon, a moderately stiff ($L_{\mathrm{sym}}=122\pm 57$ MeV and $K_{\mathrm{sym}}=229\pm 363$ MeV) symmetry energy is extracted, a result that agrees with that of a similar study that employed the UrQMD transport model and a power-law parametrization of the symmetry energy. This contrasts with diverging results extracted from the FOPI ${\pi }^{-}/{\pi }^{+}$ ratio available in the literature.

A phenomenological model of the $\beta$-delayed neutron-emission probability, based on a level density function, is presented. The effective level density systematics, empirically determined from the experimental data, are found to be relatively flat, with discontinuities at the major shell closures. These systematics have been modeled and used to determine $\beta$-delayed neutron-emission probabilities. The present model is compared to other available models and is found to provide an improved description of the $\beta$-delayed neutron-emission probabilities across the entire mass surface.

The ${}^{88}$Kr nucleus has been reinvestigated with prompt-$\gamma$-ray-spectroscopy methods using the Gammasphere Ge array to measure $\gamma$ rays following spontaneous fission of ${}^{252}$Cf. The order of some of the transitions, reported previously, has been changed and new levels were introduced. Angular correlation analysis allowed the assignment of spins to several levels in ${}^{88}$Kr. These data, together with the shell-model calculations, explained the near-yrast structure of ${}^{88}$Kr, which is similar to the structure of the $N=52$, ${}^{90}$Sr, and ${}^{92}$Zr isotones. The regular systematics obtained for the three isotones suggests that the spin of the 2073.4-keV level in the ${}^{86}$Se isotone is different from the $I=6$ value reported previously. Using data from prompt $\gamma$-ray measurement of spontaneous fission of ${}^{248}$Cm, we reinvestigated the ${}^{86}$Se nucleus. A new candidate for the 6${}_1^{+}$ level in ${}^{86}$Se has been proposed, which is supported by shell-model calculations. Energies of the 2${}_1^{+}$ and 4${}_1^{+}$ levels in the ${}^{82}$Zn nucleus have been predicted using a novel systematics.

Extended tables are presented for spectroscopic factors, asymptotic normalization coefficients and rms radii of one-nucleon overlap functions for $0p$-shell nuclei calculated in the source term approach using shell model wave functions. The tabulated data includes both new results and updates on previously published values. They are compared with recent results obtained in ab initio calculations, and with experimental data, where available. The reduction of spectroscopic factors with respect to traditional shell model values as well as its neutron-proton asymmetry is also discussed.

We redefine the surface tension coefficient and the surface symmetry energy for an asymmetric nuclear Fermi-liquid drop with a finite diffuse layer. Considering a two-component charged Fermi-liquid drop and following the Gibbs-Tolman concept, we introduce the equimolar radius $R_e$ of a sharp-surface droplet at which the surface tension is applied and the radius of the tension surface $R_s$ (Laplace radius) which provides the minimum of the surface tension coefficient $\sigma$. We have shown that the nuclear Tolman length $\xi$ is negative and the modulus of $\xi$ grows quadratically with the asymmetry parameter $X=(N-Z)/(N+Z)$.

The neutron-capture cross section for ${}^{238}\mathrm{Pu}$ was measured by using the detector for advanced neutron-capture experiments (DANCE) array, which is a highly segmented and highly efficient $4\pi$ $\gamma$-ray calorimeter. The neutron-capture events were recognized by the total $\gamma$-ray energy deposited in DANCE, which is equal to the reaction $Q$ value plus the incident neutron energy. The absolute neutron-capture cross section was derived as a function of incident neutron energy from thermal to about 30 keV. The measured cross section for incident neutron energy below 18 eV was performed for the first time by using the direct method and does not support the most recently adopted changes in endf/b-vii.1 where the neutron-capture cross section was lowered by as much as a factor of $\sim 3$ in the neighborhood of 0.3 eV from those evaluated in endf/b-vii.0.