Low-energy ${}^6\mathrm{Li}$$(d,\alpha )$${}^4\mathrm{He}$ and ${}^6\mathrm{Li}$$(d,p_0)$${}^7\mathrm{Li}$ reactions are affected by the $2^{+}$ resonance level of ${}^8\mathrm{Be}$ at $E_x\simeq 22.2$ MeV. In this work, we present a new method to extract fractions of the $2^{+}$ components of the reactions, which include the resonance, by using the tensor-analyzing powers, $T_{2q}$, of polarized deuterons. We measured $T_{2q}$ for $q=0,1,2$ at the very low incident energy $E_d=90$ keV and analyzed the data by the invariant amplitude method giving the $2^{+}$ fractions as $0.90\pm 0.05$ for ${}^6\mathrm{Li}$$(d,p)$ and $0.998\pm 0.003$ for ${}^6\mathrm{Li}$$(d,\alpha )$. For ${}^6\mathrm{Li}$$(d,p)$, it was comparable to the resonance fraction extracted from cross-section data, whereas for ${}^6\mathrm{Li}$$(d,\alpha )$, the $2^{+}$ fraction was much larger than the resonance fraction extracted from cross-section data. A part of the analyses was extended to higher energies up to 960 keV.

The implementation of π production in the Liège intranuclear cascade model (INCL4) for spallation reactions is revisited to alleviate the overestimate of the π yield. Three modifications are proposed for this purpose: a better $\pi N$ cross section at high energy, the introduction of a π average potential, and the modification of the average mass of the Δ resonance. The π potential is determined from a global fit of a set of data bearing on π production in proton-induced reactions, on $\pi$-nucleus and absorption cross sections, and on proton production in π-induced reactions. The resulting π potential is poorly determined in the nuclear interior and agrees with the phenomenological optical-model potentials in the surface region. With these modifications, the predictions of the INCL4 model concerning π production cross sections in proton-induced reactions are considerably improved. Predictions of the improved version for $\pi$-nucleus reaction and absorption cross sections and for proton, residue, and fission cross sections in π-induced reactions are also presented and shown to give reasonably good agreement. Neutron production and some aspects of fission in π-induced reactions are also investigated and reasonably well predicted. Effects on the modifications on observables, which are not directly linked with π's, such as the neutron yield and the residue mass and charge spectra in proton-induced reactions are also investigated and shown to improve the description of these observable quantities. Several results on π production and the relative insentivity to the π potential in the nuclear interior are shown to be consistent with the fact that most π's are not produced in early collisions. Importance of rescattering in π absorption on nuclei is also pointed out. A comparison is made with the so-called Δ-hole model. Residual discrepancies are identified and are interpreted as due to the lack of π interaction with two nucleons at low energy, to the neglect of quantum motion effects, and to a possible underestimate of rescattering.

Induced polarization and analyzing power data for exclusive proton-induced proton knockout from the $1s_{1/2}$-state in ${}^{12}\mathrm{C}$—at incident energies of 392 MeV and 1 GeV and for kinematics corresponding to zero recoil momentum—are studied within the framework of both relativistic and nonrelativistic distorted wave models based on the impulse approximation. We also study to which extent relativistic dynamical effects can be simulated in the nonrelativistic Schrödinger-equation-based distorted wave model via the introduction of effective nucleon mass corrections (within the context of the Walecka model of quantum hadrodynamics) to the nucleon-nucleon $(\mathit{NN})$ scattering matrix. A quantitative description of the data is achieved by invoking density-dependent corrections to the $\mathit{NN}$ amplitudes within the framework of our relativistic distorted wave model.

Neutrinos in core-collapse supernovae are likely trapped by neutrino-nucleus elastic scattering. Using molecular dynamics simulations, we calculate neutrino mean free paths and ion-ion correlation functions for heterogeneous plasmas. Mean free paths are systematically shorter in plasmas containing a mixture of ions compared to a plasma composed of a single ion species. This is because neutrinos can scatter from concentration fluctuations. The dynamical response function of a heterogeneous plasma is found to have an extra peak at low energies describing the diffusion of concentration fluctuations. Our exact molecular dynamics results for the static structure factor reduce to the Debye-Hückel approximation, but only in the limit of very low momentum transfers.

We show that the observed suppression of the $\Lambda (1520)/\Lambda$ ratio in central Au+Au collisions at the BNL Relativistic Heavy Ion Collider can be naturally understood in the constituent quark recombination model.

It is shown that the available experimental data on the energies of the first and the γ-vibrational $2^{+}$ states and the reduced $E2$ transition probabilities from these states to the ground state require for the explanation significantly different values of the mass coefficients for the rotational motion and γ-vibrations.

The contributions to the cross sections of intermediate energy two-nucleon knockout reactions from events in which one nucleon is removed by the stripping (inelastic breakup) mechanism and a second by the diffraction (elastic breakup) mechanism are discussed. The small additional contributions from two-nucleon diffraction events are also estimated. The approach used combines the eikonal reaction and shell model structure theory frameworks. For reactions involving the removal of two well-bound like nucleons, at incident energies of order 100 MeV per nucleon, the additional cross sections are shown to be of approximately the same size as those from events in which both nucleons are stripped in inelastic interactions. These more complete dynamical calculations now permit a quantitative comparison of the theoretical cross sections with recent partial cross-section measurements of the two-neutron (two-proton) removal reactions from neutron-deficient (neutron-rich) nuclei. As has been observed in both nuclear- and electron-induced single-nucleon knockout reaction analyses, the theoretical two-nucleon knockout cross sections overestimate the measured values, requiring a suppression of the two nucleon shell-model transition strengths. The deduced two-nucleon suppression factors, $R_s(2N)$, are consistent with a value of 0.5 for each of the five reactions considered.

A nucleon-nucleus interaction model has been applied to ascertain the underlying character of the negative-parity spectra of four isobars of mass-7, from neutron- to proton-emitter drip lines. With a single nuclear potential defined by a simple coupled-channel model, a multichannel algebraic scattering approach (MCAS) has been used to determine the bound and resonant spectra of the four nuclides, of which ${}^7\mathrm{He}$ and ${}^7\mathrm{B}$ are particle unstable. Incorporation of Pauli blocking into the model enables a description of all known spin-parity states of the mass-7 isobars. We have also obtained spectra of similar quality by using a large space no-core shell model. Additionally, we have studied ${}^7\mathrm{Li}$ and ${}^7\mathrm{Be}$ using a dicluster model. We have found a dicluster-model potential that can reproduce the lowest four states of the two nuclei, as well as the relevant low-energy elastic scattering cross sections. But, with this model, the rest of the energy spectra cannot be obtained.

The lifetime of the $J^{\pi }=2_1^{+}$ state of ${}^{170}\mathrm{Hf}$ at 100.8 keV was measured. Excited states of ${}^{170}\mathrm{Hf}$ were populated with the ${}^{158}\mathrm{Gd}$(${}^{16}\mathrm{O}$,4nγ) reaction at the TANDEM-LINAC facility of the State University of New York (SUNY) at Stony Brook. A lifetime of $\tau =1.74\pm 0.06$ ns was found using the delayed γ-radiofrequency coincidence method with respect to the pulsed LINAC beam. It corresponds to an $E2$ transition strength of $181\pm 6$ W.u. to the $J^{\pi }=0_1^{+}$ ground state. With its increased precision, by one order of magnitude with respect to previous literature, this value serves as a normalization parameter for collective models for this nucleus.

Within a relativistic single particle model, we calculate the Coulomb sum rule of inclusive electron scattering from ${}^{40}\mathrm{Ca}$ and ${}^{208}\mathrm{Pb}$ in the quasielastic region. Theoretical longitudinal and transverse structure functions are extracted for three-momentum transfers from 300 to 500 MeV/$c$ and compared with the experimental data measured at Bates and Saclay. We find that there is no drastic suppression of the longitudinal structure function and that the Coulomb sum rule depends on the nucleus in our theoretical model.

We formulate the self-consistent separable random phase approximation (SRPA) method and specify it for Skyrme forces with pairing for the case of axially symmetric deformed nuclei. The factorization of the residual interaction allows diagonalization of high-ranking RPA matrices to be avoided, which dramatically reduces the computational expense. This advantage is crucial for the systems with a huge configuration space, first of all for deformed nuclei. SRPA self-consistently takes into account the contributions of both time-even and time-odd Skyrme terms as well as of the Coulomb force and pairing. The method is implemented to describe isovector E1 and isoscalar E2 giant resonances in a representative set of deformed nuclei: ${}^{154}\mathrm{Sm}$, ${}^{238}\mathrm{U}$, and ${}^{254}\mathrm{No}$. Four different Skyrme parameterizations (SkT6, SkM${}^{*}$, SLy6, and SkI3) are employed to explore the dependence of the strength distributions on some basic characteristics of the Skyrme functional and nuclear matter. In particular, we discuss the role of isoscalar and isovector effective masses and their relation to time-odd contributions. The high sensitivity of the right flank of E1 resonance to different Skyrme forces and the related artificial structure effects are analyzed.

We report on $p\text{−}\Lambda ,p\text{−}\overline{\Lambda },\overline{p}\text{−}\Lambda$, and $\overline{p}\text{−}\overline{\Lambda }$ correlation functions constructed in central Au-Au collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV by the STAR experiment at RHIC. The proton and lambda source size is inferred from the $p\text{−}\Lambda$ and $\overline{p}\text{−}\overline{\Lambda }$ correlation functions. It is found to be smaller than the pion source size also measured by the STAR experiment at smaller transverse masses, in agreement with a scenario of a strong universal collective flow. The $p\text{−}\overline{\Lambda }$ and $\overline{p}\text{−}\Lambda$ correlation functions, which are measured for the first time, exhibit a large anticorrelation. Annihilation channels and/or a negative real part of the spin-averaged scattering length must be included in the final-state interactions calculation to reproduce the measured correlation function.

We calculate at two-loop order in chiral perturbation theory the electromagnetic corrections to the two-pion exchange nucleon-nucleon interaction that is generated by the isovector spin-flip $\pi \pi \mathit{NN}$ contact-vertex proportional to the large low-energy constant $c_4\simeq 3.4{\mathrm{GeV}}^{-1}$. We find that the respective $2\pi \gamma$-exchange potentials contain sizable isospin-breaking components which reach up to −4% of corresponding isovector $2\pi$-exchange potentials. The typical values of these novel charge-independence breaking spin-spin and tensor potentials are −0.11 and 0.09 MeV, at a nucleon distance of $r=m_{\pi }^{-1}=1.4$ fm. The charge-symmetry breaking spin-spin and tensor potentials come out a factor of $2.4$ smaller. Our analytical results for these presumably dominant isospin-violating spin-spin and tensor $\mathit{NN}$-forces are in a form such that they can be easily implemented into phase-shift analyses and few-body calculations.

The γ spectroscopy of ${}^{25,27}\mathrm{Ne}$ and ${}^{26,27}\mathrm{Na}$ was studied from the reaction of ${}^{26}\mathrm{Ne}$ with a deuterium target in inverse kinematics at 9.7 MeV/nucleon. The selectivity of the $(d,p),(d,t)$, and $(d,n)$ transfer reactions provides new spectroscopic information on low-lying states. The validity of the $\mathit{sd}$ shell-model space for these nuclei is discussed.

Evaporation residue cross sections and spin distributions have been measured for ${}^{200}\mathrm{Pb}$ compound nucleus formed in ${}^{16}\mathrm{O}+{}^{184}\mathrm{W}$ reaction at the laboratory beam energies of 84, 92, 100, 108, 116, and 120 MeV. The evaporation residues have been selected using the recoil mass spectrometer, HIRA and detected using a 2D position sensitive silicon detector. The evaporation residue spin distributions have been measured by detecting gamma rays with 14 element BGO multiplicity filter. Measured evaporation residue cross sections and spin distributions are compared with the values predicted by a standard statistical model code. Comparison shows that, in the energy region studied, the nuclear viscosity parameter $\gamma =3$ is required to explain total evaporation residue cross sections and evaporation residue spin distributions.

Isospin effects on the optical potentials of kaons and antikaons in dense hadronic matter are investigated using a chiral SU(3) model. These effects are important for asymmetric heavy-ion collision experiments. In the present work, the dispersion relations are derived for kaons and antikaons, compatible with the low-energy scattering data, within our model approach. The relations result from the kaonic interactions with the nucleons, vector mesons, and scalar mesons in the asymmetric nuclear matter. The isospin asymmetry effects arising from the interactions with the vector-isovector ρ meson as well as the scalar-isovector δ mesons are considered. The density dependence of the isospin asymmetry is seen to be appreciable for the kaon and antikaon optical potentials. This dependence can be particularly relevant to the future Facility for Antiproton and Ion Research (FAIR) at GSI, where experiments using neutron-rich beams are planned to be used in the study of compressed baryonic matter.

The effects of hadronic rescattering in high energy relativistic Au+Au collisions are studied using two very different models to describe the early stages of the collision. One model is based on a hadronic thermal picture and the other on a superposition of parton-parton collisions. Operationally, the output hadrons from each of these models are used as input to a hadronic rescattering calculation. The results of the rescattering calculations from each model are then compared with rapidity and transverse momentum distributions from the BNL Relativistic Heavy Ion Collider BRAHMS experiment. In spite of the different points of view of the two models of the initial stage, after rescattering, the observed differences between the models are mostly “washed out” and both models give observables that agree roughly with each other and with experimental data.

The Paschos-Wolfenstein (PW) relation joins neutral- and charged-current neutrino- and antineutrino-induced cross sections into an expression that depends on the weak mixing angle $\sin {}^2{\theta }_W$. Contrary to the traditional approach with partonic degrees of freedom, we adopt a model built on hadronic degrees of freedom to perform a study of the PW relation at intermediate neutrino energies (100 MeV to 2 GeV). Running and upcoming high-statistics scattering experiments such as MiniBooNE, MINERνA, FINeSSE and beta-beam experiments make a scrutiny of the PW relation timely. Employing a relativistic Glauber nucleon knockout model for the description of quasielastic neutrino-nucleus reactions, the influence of nuclear effects on the PW relation is investigated. We discuss nuclear model dependences and show that the PW relation is a robust ratio, mitigating the effect of final-state interactions, for example, to the $1\%$ level. The role played by a possible strangeness content of the nucleon is investigated. It appears that the uncertainties arising from the poorly known strangeness parameters and the difficulties in nuclear modeling seriously limit the applicability of the PW relation as an intermediate-energy electroweak precision tool. On the other hand, we show that nuclear effects may be sufficiently well under control to allow the extraction of new information on the axial strangeness parameter. Results are presented for ${}^{16}\mathrm{O}$ and ${}^{56}\mathrm{Fe}$.

We formulate a new Bardeen-Cooper-Schrieffer (BCS)-type theory at finite temperature, by deriving a set of variational equations of the free energy after the particle-number projection. With its broad applicability, this theory can be a useful tool for investigating the pairing phase transition in finite systems with the particle-number conservation. This theory provides effects of the symmetry-restoring fluctuation (SRF) for the pairing phenomena in finite fermionic systems, distinctively from those of additional quantum fluctuations. It is shown by numerical calculations that the phase transition is compatible with the conservation in this theory, and that the SRF shifts up the critical temperature ($T^{\mathrm{cr}}$). This shift of $T^{\mathrm{cr}}$ occurs due to reduction of degrees-of-freedom in canonical ensembles, and decreases only slowly as the particle-number increases (or as the level spacing narrows), in contrast to the conventional BCS theory.