Resonance states of ${}^5\mathrm{H}$ and ${}^5\mathrm{Be}$ have been studied using microscopic $t+n+n$ and $h+p+p$ three-cluster models, respectively. The resonance positions are localized by the three-body complex scaling method. An effective nucleon-nucleon interaction, which reproduces the $\alpha +N$ low energy phase shifts and the energies of the $0^{+}$ ground and $2^{+}$ first excited states of ${}^6\mathrm{He}$ with the three-cluster model, is used to calculate resonance states of ${}^5\mathrm{H}$ and ${}^5\mathrm{Be}.$ This model can reasonably reproduce the experimental $t+n$ and $h+p$ phase shifts at low energies. It gives a ${1/2}^{+}$ broad resonance as the ground state in ${}^5\mathrm{H}$ and ${}^5\mathrm{Be}$ and in addition it gives two excited resonance states of ${3/2}^{+}$ and ${5/2}^{+}.$ The resonance parameters of the ${1/2}^{+}$ state of ${}^5\mathrm{H}$ in the present model are close to those deduced from their recent experimental data by Korsheninnikov et al. The same effective nucleon-nucleon interaction is used for a tentative investigation in order to explore the possibility of a tetra-neutron ${(}^{4}n)$ resonance by means of the $n+n+n+n$ four-body complex scaling method on a restricted set of model configurations. Our model does not give any evidence for a tetraneutron resonance.

The ${}^{14}\mathrm{C}{(}^{14}\mathrm{C},\alpha )$ reaction at 22 MeV was used to study $T=2\mathrm{}$ ${}^{24}\mathrm{Ne}.$ Charged particles were detected with a Si detector telescope at $0°,$ and $\gamma$ transitions in coincidence were detected with an array of three Compton-suppressed “clover” detectors and seven Compton-suppressed single Ge crystals. The $\alpha -\gamma$ and $\alpha -\gamma -\gamma$ coincidence data were analyzed to study the structure of ${}^{24}\mathrm{Ne}.$ Twenty-two new $\gamma$ lines were assigned to 14 new levels. Angular distribution measurements provided spin assignments and restrictions to a number of levels. Likely candidates were found for the lowest $5^{+}$ and $6^{+}$ levels. All but one of the 12 states predicted to lie below 6 MeV by shell model calculations using the universal $s-d$ interaction were observed. The rms deviation in excitation energies among these is 190 keV, and there is a tendency for the observed levels to lie somewhat higher than the predicted ones. A comparison of the structure of ${}^{24}\mathrm{Ne}$ with its neighbors suggests a significant shell gap above the $\nu d_{5/2}$ orbital in agreement with the large $d_{5/2}-s_{1/2}$ gap implied by the effective single-particle energies in the universal $s-d$ shell model interaction.

A measurement of the photon asymmetry $\left({\alpha }_{\gamma }\right)$ in radiative muon capture RMC on ${}^{40}\mathrm{Ca}$ has been carried out at TRIUMF. Negative muons were stopped in a ${}^{40}\mathrm{Ca}$ target and the resulting RMC photons were then converted by a 5-cm thick NaI detector placed immediately in front of our main NaI detector, a cylindrical crystal of diameter 46 cm and depth 51 cm. The data sample consisted of 5200 high-energy $(57\mathrm{}\mathrm{MeV}<E_{\gamma }<95\mathrm{}\mathrm{MeV})$ RMC photon candidates. Our measured value for the energy-averaged photon asymmetry is ${\alpha }_{\gamma }=1.00\mathrm{}\pm \mathrm{0.23.}$ The extracted values for the induced pseudoscalar coupling constant ${(g}_P)$ based on this photon asymmetry measurement are $g_P{/g}_A<8.0,$ utilizing the impulse approximation IA model, and $g_P{/g}_A<14.5\mathrm{}$ in terms of the modified impulse approximation (MIA) model. The two extracted values, although both consistent with the Goldberger-Treiman value of $g_P{/g}_A\approx 7,$ are considerably different, indicating a significant theoretical model dependency.

Directed and elliptic flow measurements for charged pions and protons are reported as a function of transverse momentum, rapidity, and centrality for $40A$ and $158A\mathrm{GeV}$ $\mathrm{Pb}+\mathrm{Pb}$ collisions, as recorded by the NA49 detector. Both the standard method of correlating particles with an event plane and the cumulant method of studying multiparticle correlations are used. In the standard method the directed flow is corrected for conservation of momentum. In the cumulant method elliptic flow is reconstructed from genuine four-, six-, and eight-particle correlations, showing the first unequivocal evidence for collective motion in $A+A$ collisions at SPS energies.

Using a covariant coalescence model, we study hadron production in relativistic heavy ion collisions from both soft partons in the quark-gluon plasma and hard partons in minijets. Including transverse flow of soft partons and independent fragmentation of minijet partons, the model is able to describe available experimental data on pion, kaon, and antiproton spectra. The resulting antiproton to pion ratio is seen to increase at low transverse momenta and reaches a value of about 1 at intermediate transverse momenta, as observed in experimental data at RHIC. A similar dependence of the antikaon to pion ratio on transverse momentum is obtained, but it reaches a smaller value at intermediate transverse momenta. At high transverse momenta, the model predicts that both the antiproton to pion and the antikaon to pion ratio decrease and approach those given by the perturbative QCD. Both collective flow effect and coalescence of minijet partons with partons in the quark-gluon plasma affect significantly the spectra of hadrons with intermediate transverse momenta. Elliptic flows of phi mesons and baryons such as protons, lambdas, cascades, and omegas have also been evaluated from partons with elliptic flows extracted from fitting measured pion and kaon elliptic flows. The predicted proton and lambda elliptic flows are consistent with available experimental data.

In a recent experiment E906 at the BNL-AGS, in which a search for light $S=-2$ hypernuclei was carried out, strong evidence for the nuclide ${}_{\Lambda \Lambda }^{\hspace{1em}4}\mathrm{H}$ was found. One of the most striking components of this data was the appearance of a narrow low-momentum ${\pi }^{-}$ line at $k_{\pi }=104\mathrm{}–105\mathrm{MeV}/c.\mathrm{}$ This was ascribed to the decay of ${}_{\Lambda \Lambda }^{\hspace{1em}4}\mathrm{H}$ into a resonant state in ${}_{\Lambda }^4\mathrm{He}.$ The existence of such a state is shown to be plausible and its characteristics delineated.

We investigate the structure of the SU(3) octet and decuplet baryons employing a constituent chiral quark model. We solve the ground and s- and p-wave excited states of the three-quark system with many range Gaussian bases. This method, which we employ here, has been shown to work quite nicely to describe the structure of the SU(3) s-wave baryons. In this work, we extend our research to the SU(3) p-wave baryons including the tensor term. It is found that the mass differences between positive and negative parity states are well reproduced. It is also found that the pseudoscalar (ps) meson exchange potential plays a very important role to lower the mass of the nucleon resonance $N^{*}\mathrm{}\left(1440\right)\mathrm{}$ (Roper). We also discuss how the semirelativistic approach works in the chiral quark model and how to treat the potential terms consistently in the semirelativistic approach.

Measurements of the fusion of ${}^{16}\mathrm{O}$ and ${}^{27}\mathrm{Al}$ with a series of germanium isotopes are analyzed within a coupled-channels approach. It is found that couplings based interactions that are linear in the deformation amplitudes are insufficient in reproducing the data. In order to obtain reasonable fits, it is necessary also to include couplings based on quadratic interactions. The analysis suggests that the nuclear radius of ${}^{72}\mathrm{Ge}$ is significantly smaller than predicted from a smooth interpolation between other germanium isotopes. The large prolate deformation of ${}^{74}\mathrm{Ge},$ which has been proposed as the preferred solution to measurements of the quadrupole moment of the $2^{+}$ state, is not supported by the analysis; the near spherical solution is more likely.

We present a comprehensive analysis of deep inelastic scattering from ${}^3\mathrm{He}$ and ${}^3\mathrm{H},$ focusing in particular on the extraction of the free neutron structure function $F_2^n.$ Nuclear corrections are shown to cancel to within 1–2% for the isospin-weighted ratio of ${}^3\mathrm{He}$ to ${}^3\mathrm{H}$ structure functions, which leads to more than an order of magnitude improvement in the current uncertainty in the neutron to proton ratio $F_2^n{/F}_2^p$ at large x. Theoretical uncertainties originating from the nuclear wave function, including possible non-nucleonic components, are evaluated. Measurements of the ${}^3\mathrm{He}$ and ${}^3\mathrm{H}$ structure functions will, in addition, determine the magnitude of the EMC effect in all $A<~3$ nuclei.

Final results of the double $\beta$ decay experiment, performed with the help of low background ${}^{116}{\mathrm{CdWO}}_4$ crystal scintillators in the Solotvina Underground Laboratory, are presented. In particular, the revised half-life value of the two-neutrino 2β decay of ${}^{116}\mathrm{Cd}$ has been measured as $T_{1/2}^{2\nu }{=2.9\mathrm{}}_{-0.3}^{+0.4\mathrm{}}\times {10}^{19}\mathrm{yr},$ and the new half-life limit on the neutrinoless $2\beta$ decay of ${}^{116}\mathrm{Cd}$ has been established as $T_{1/2}^{0\nu }>~1.7\left(2.6\right)\mathrm{}\times {10}^{23}\mathrm{yr}$ at 90% (68%) C.L. The latter corresponds to a restriction on the neutrino mass: $m_{\nu }<~1.7\left(1.4\right)\mathrm{}\mathrm{eV}$ at 90% (68%) C.L. Besides, new $T_{1/2}$ bounds (at the level of ${10}^{17}–{10}^{21}\mathrm{yr})$ were set for various $2\beta$ processes in ${}^{106}\mathrm{Cd},$ ${}^{108}\mathrm{Cd},$ ${}^{114}\mathrm{Cd},$ ${}^{180}\mathrm{W},$ and ${}^{186}\mathrm{W}$ nuclei.

Following the Caldeira-Leggett approach to describe dissipative quantum systems the structure function for a harmonic oscillator with Ohmic dissipation is evaluated by an analytic continuation from Euclidean to real time. The analytic properties of the Fourier transform of the structure function with respect to the energy transfer (the “characteristic function”) are studied and utilized. In the one-parameter model of Ohmic dissipation we show explicitly that the broadening of excited states increases with the state number without violating sum rules. Analytic and numerical results suggest that this is a phenomenologically relevant, consistent model to include the coupling of a single (sub)nuclear particle to unobserved and complex degrees of freedom.

Neutrons from the fusion reactions ${}^{16}\mathrm{O}{+}^{64}\mathrm{Zn}$ at 91 MeV and ${}^{32}\mathrm{S}{+}^{48}\mathrm{Ti}$ at 120 and 125 MeV have been observed in two series of complementary experiments using the time of flight technique. The energies are selected so that both the systems lead to the compound nucleus ${}^{80}{\mathrm{Sr}}^{*}$ with the same value of the angular momentum and the excitation energy. The spectra from the asymmetric reaction ${}^{16}\mathrm{O}{+}^{64}\mathrm{Zn}$ are found to be consistent with the predictions of the statistical model calculations using rotating liquid drop model values of the moment of inertia and the transmission coefficients for the spherical nuclei in the inverse absorption channel. However, the experimental spectra in the case of the symmetric reaction ${}^{32}\mathrm{S}{+}^{48}\mathrm{Ti}$ show deviations at higher as well as lower energies from the normal statistical model calculations. This indicates the effect of the entrance channel on the dynamics of the neutron evaporation of the compound system. The effective level density parameter a is found to be smaller, indicating the evaporation at a higher temperature, for the same compound nucleus formed in the case of the symmetric system as compared to the asymmetric system.

Different measures of net-charge fluctuations in ultrarelativistic heavy-ion interactions, namely, $v\left(Q\right),$ $v\left(R\right),$ $\Gamma$ and ${\nu }_{\mathrm{dyn}},$ are discussed and compared. Their behaviors are confronted in the context of different experimental scenarios. It is found that the ${\nu }_{\mathrm{dyn}}$ observable exhibits most of the experimentally desirable features. The $v\left(Q\right)\mathrm{}$ and $\Gamma$ observables are also appropriate although proper care must be taken of finite acceptance and efficiency effects. Two simple charged particle production models are considered; production via neutral resonance decay and hadronization from a quark-gluon plasma. The study reveals that dynamical correlations, arising in such models, strongly influence the measures.

We have searched even-even nuclei with $Z>~20,$ $N>~20$ to find examples displaying the predicted characteristics of X(5) critical point behavior. On the basis of the yrast state energies and yrast intraband transition strengths, the best candidates are ${}^{126}\mathrm{Ba},$ ${}^{130}\mathrm{Ce},$ and the previously suggested examples of the $N=90\mathrm{}$ isotones of Nd, Sm, Gd, and Dy.

A new procedure is developed for calculating the charge, mass, and kinetic energy distributions of quasifission products. The quasifission is treated within a transport model which describes a master equation for the evolution of the dinuclear system in charge and mass asymmetries and its decay along the internuclear distance. The calculated yields of quasifission products and their distributions in kinetic energy are in agreement with recent experimental data of hot fusion reactions leading to superheavy nuclei. The importance of shell and deformation effects in quasifission is noted. The preneutron and postneutron emissions as well as the fission of a heavy nucleus in the dinuclear system are considered.

We study the numerical solution of hard dense loop (HDL) color superconductivity gap equation in the momentum space. We investigate the validity of various approximations for the HDL gap equation with a weak coupling constant g. We find that the standard approximations to derive the leading gap equation to g-leading order are essential for a secure numerical evaluation of the logarithmic singularity with a small g. The leading integral gap equation with a small g should be inverted to a soft integral gap equation to smear the logarithmic singularity near the Fermi surface. The HDL gap equation is solved for a rather large coupling constant $g>~2.0,$ while the leading and soft integral gap equations are solved for a small coupling constant $g<~1.$ When their solutions near the Fermi surface are extrapolated to larger g values, they coincide with the HDL gap equation. Furthermore, the analytical solution matches the numerical one up to order $O\left(1\right).$ Our results confirm the previous estimates derived by other approximations that the gap energy is of the order of 10–100 MeV for a chemical potential $\mu <~1000\mathrm{MeV}.$ They also support the validity of leading approximations applied to the HDL gap equation near the Fermi surface and a small g to derive the soft integral gap equation and its analytical solution.

The variation of average transverse mass of identified hadrons with charge multiplicity has been studied for AGS, SPS, and RHIC energies. The observation of a plateau in the average transverse mass for multiplicities corresponding to SPS energies is attributed to the formation of a coexistence phase of quark gluon plasma and hadrons. A subsequent rise for RHIC energies may indicate a deconfined phase in the initial state. Several possibilities which can affect the average transverse mass are discussed. Constraints on the initial temperature and thermalization time have been put from the various experimental data available at SPS energies.

A model proton wave function, constructed using Poincaré invariance and constrained by recent electromagnetic form factor data, is used to study the shape of the proton. Spin-dependent quark densities are defined as matrix elements of density operators in proton states of definite polarization, and shown to have an infinite variety of nonspherical shapes. For high momentum quarks with spin parallel to that of the proton, the shape resembles that of a peanut, but for quarks with antiparallel spin the shape is that of a bagel.

In order to investigate the charge symmetry breaking (CSB) in the short-range part of the nuclear force, we calculate the difference of the masses of the neutron and the proton, $\Delta M,$ the difference of the scattering lengths of the $p-p$ and $n-n$ scatterings, $\Delta a,$ and the difference of the analyzing power of the proton and the neutron in the $n-p$ scattering, $\Delta A\left(\theta \right),$ by a quark model. In the present model the sources of CSB are the mass difference of the up and down quarks and the electromagnetic interaction. We investigate how much each of them contributes to $\Delta M,$ $\Delta a,$ and $\Delta A\left(\theta \right).\mathrm{}$ It is found that the contribution of CSB of the short-range part in the nuclear force is large enough to explain the observed $\Delta A\left(\theta \right),$ while $\Delta a$ is rather underestimated.