Evaporation residue (ER) excitation function and $\gamma$-ray multiplicity in coincidence with ER’s have been measured for the ${}^{19}\mathrm{F}{+}^{175}\mathrm{Lu}$ system for studying the spin dependence of dissipation effects in fission. A combined analysis of total ER cross section and the spin distribution data confirms that there is no onset of dissipation in the presaddle region of the fission process.

The strengths of low-energy resonances in ${}^{14}\mathrm{N}(\alpha ,\gamma {)}^{18}\mathrm{F}$ at 573 keV and 1136 keV have been measured using an activation method. In addition, their relative strength and the energy of the lower resonance have been determined in a prompt $\gamma$-ray experiment. The results of these measurements are used to reevaluate the stellar reaction rate of ${}^{14}\mathrm{N}(\alpha ,\gamma {)}^{18}\mathrm{F}.$ The present reaction rate at temperatures of astrophysical interest is a factor of 2 smaller than previously reported.

$\alpha$ decay measurements for ${}^{162}\mathrm{Os},$ ${}^{158}\mathrm{W},$ and ${}^{158m}\mathrm{W}$ are presented. ${}^{162}\mathrm{Os}$ was produced via fusion evaporation of a 270 MeV ${}^{58}\mathrm{Ni}$ beam on a ${}^{106}\mathrm{Cd}$ target and then implanted in a doubled-sided silicon strip detector (DSSD). The ${}^{162}\mathrm{Os}{-}^{158}\mathrm{W}\mathrm{}$ $\alpha$-decay mother-daughter correlation was then studied. ${}^{158m}\mathrm{W}$ was directly populated in a similar experiment with a ${}^{102}\mathrm{Pd}$ target. Using the measurements obtained for ${}^{162}\mathrm{Os}$ $[E_{\alpha }=6600\mathrm{}(3)\mathrm{}$ keV, $t_{1/2}=1.9\mathrm{}\left(2\right)\mathrm{}$ ms], ${}^{158}\mathrm{W}$ $[E_{\alpha }=6445\mathrm{}(3)\mathrm{}$ keV, $t_{1/2}=1.5\mathrm{}\left(2\right)\mathrm{}$ ms, $b_{\alpha }=96\mathrm{}\left(6\right)\%],$ and ${}^{158m}\mathrm{W}$ $[E_{\alpha }=8286\mathrm{}(7)\mathrm{}$ keV, $t_{1/2}=0.14\mathrm{}\left(2\right)\mathrm{}$ ms], $\alpha$-reduced widths were calculated.

In order to investigate their effect on the triton binding energy, a set of nonlocal ${}^1{S}_0$ and ${}^3{\mathrm{SD}}_1$ nucleon-nucleon $\mathrm{}\left(\mathrm{NN}\right)\mathrm{}$ interactions is constructed in coordinate space. The properties which make possible the reproduction of the triton binding energy without a three-nucleon force are studied. For all of the investigated local and nonlocal interactions the dominant contribution to the triton binding energy comes from the pole terms of the ${}^1{S}_0$ and ${}^3{\mathrm{SD}}_1$ states; consequently the singlet virtual bound state and deuteron properties have a dominant role. Low deuteron D-state and substantial S-state short-distance probabilities, which could not be produced by local $\mathrm{NN}$ interactions, are necessary requirements for the correct binding energy.

Stopped-${\Xi }^{-12}\mathrm{C}$ reactions have been investigated with respect to H-dibaryon and hypernucleus formation with a scintillating fiber detector. Out of $5.5\times {10}^3$ tagged ${\Xi }^{-}$ particles via the ${(K}^{-}{,K}^{+})$ reaction we obtained 72 stopping ${\Xi }^{-}$ events with ${6.7}_{-1.4}^{+1.1\mathrm{}}$ background events after imposing kinematic constraints. Hypernuclear production has been studied by observing free Λ decays in the stopped-${\Xi }^{-}$ reactions. From the observed Λ momentum spectrum, we have found the hypernuclear production rates to be $18\pm 13,$ $65\pm 6,$ and $17\pm 12\%$ for double/twin-Λ hypernucleus, single-Λ hypernucleus, and no hypernucleus cases, respectively. With the same sample, we set upper limits on R (stopped-${\Xi }^{-12}\overrightarrow{C}\mathrm{HX}$ /stopped-${\Xi }^{-12}\overrightarrow{C}$ all) for $H$ decaying into $\Lambda n,$ ${\Sigma }^{-}p,$ and $\Lambda p{\pi }^{-},$ for $H$ masses just below $\Lambda \Lambda$ mass threshold and for $H$ lifetime range ${10}^{-11}<~{\tau }_H<~{10}^{-8}\hspace{0.5em}\mathrm{s}.$ The upper limits on $R$ are $\sim 0.1–0.2,$ assuming all of the $H$ decay into each decay mode. Our results give a tight constraint on the existence of the bound $H,$ in comparison with the theoretical estimates of Aerts and Dover, albeit with different target nuclei.

We investigate the difference between those relativistic models based on interpreting a realistic nucleon-nucleon interaction as a perturbation of the square of a relativistic mass operator and those models that use the method of Kamada and Glöckle to construct an equivalent interaction to add to the relativistic mass operator. Although both models reproduce the phase shifts and binding energy of the corresponding nonrelativistic model, they are not scattering equivalent. The example of elastic electron-deuteron scattering in the one-photon-exchange approximation is used to study the sensitivity of three-body observables to these choices. Our conclusion is that the differences in the predictions of the two models can be understood in terms of the different ways in which the relativistic and nonrelativistic S matrices are related. We argue that the mass squared method is consistent with conventional procedures used to fit the Lorentz-invariant cross section as a function of the laboratory energy.

Various opportunities to investigate the short-range $\mathrm{NN}$ wave function are discussed, having in mind, in particular, the quark degrees of freedom. It is shown that hard bremsstrahlung in the process $p\overrightarrow{p}\mathrm{pp}\gamma$ at proton beam energies of 350–500 MeV discriminates efficiently $\mathrm{pp}$-wave functions with the short-range nodes in S and P waves that correspond to the Moscow potential of the $\mathrm{NN}$ interaction and wave functions obtained with repulsive core mesonic potentials. In the regions of maximal photon energies in the c.m. system (it means forward and backward photon emission angles in the laboratory frame) the $p\overrightarrow{p}\mathrm{pp}\gamma$ cross section calculated with the Moscow potential has maxima which are 3–5 times larger in comparison to that for repulsive core mesonic potentials. The analyzing power $A_y$ is calculated too, but it is not very sensitive to the kind of $\mathrm{NN}$ potential used. The coordinate representation formalism of the bremsstrahlung theory is exposed.

The measurement of the half-life of the superallowed positron decay of ${}^{38}{\mathrm{K}}^m$ has been studied with particular reference to possible systematic effects involved. A value of 924.4(6) ms has been found. A recommendation is made that certain earlier values are rejected, and that a mean lifetime of 924.24(27) ms is accepted. This leads to an $\mathrm{Ft}$ value of 3071.8(19) s, where the overwhelming contribution to the error comes from uncertainties in the electromagnetic corrections.

The neutron spin-orbit density contributes to the nuclear charge density as a relativistic effect. The contribution is enhanced by the effective mass stemming from the Lorentz-scalar potential in relativistic models. This enhancement plays an important role to explain the difference between the cross sections of elastic electron scattering off ${}^{40}\mathrm{Ca}$ and ${}^{48}\mathrm{Ca}$ which is not reproduced in the present nonrelativistic models. The spin-orbit density will be examined in more detail in electron scattering off unstable nuclei which would be available in the future.

The first $\left(\overrightarrow{e}{,e}^{\prime }\overrightarrow{p}\right)$ polarization transfer measurements on a nucleus heavier than deuterium have been carried out at Jefferson Laboratory. Transverse and longitudinal components of the polarization of protons ejected in the reaction ${}^{16}\mathrm{O}\left(\overrightarrow{e}{,e}^{\prime }\overrightarrow{p}\right)$ were measured in quasielastic perpendicular kinematics at a $Q^2$ of 0.8 $(\mathrm{GeV}{/c)}^2.$ The data are in good agreement with state of the art calculations.

Two- and three-pion correlations are investigated in cases when a disoriented chiral condensate (DCC) occurs. A chaoticity and weight factor are used as measures of two- and three-pion correlations, and the various models for the DCC are investigated. Some models are found to yield the chaoticity and weight factor in a reasonable agreement with recent experimental data.

High-spin states in ${}^{59}\mathrm{Cu}$ were populated using the fusion-evaporation reactions ${}^{28}\mathrm{Si}{+}^{40}\mathrm{Ca}$ at a beam energy of 125 MeV and ${}^{36}\mathrm{Ar}{+}^{28}\mathrm{Si}$ at a beam energy of 143 MeV. The Gammasphere array in conjunction with ancillary detector systems allowed for the identification of a superdeformed rotational band in ${}^{59}\mathrm{Cu},$ which was firmly linked to low-spin yrast states. Using directional correlations of oriented states, a spin-parity assignment of $I^{\pi }{=25/2\mathrm{}}^{+}$ to the band head was possible. The average quadrupole moment of the band is measured to be $Q_t=(2.24\mathrm{}\pm 0.40)\hspace{0.5em}e\mathrm{b}.$ The characteristics of the band are compared to neighboring nuclei and predictions of different mean-field theories.

A dispersion relation formalism for the virtual Compton scattering (VCS) reaction on the proton is presented, which for the first time allows a dispersive evaluation of four generalized polarizabilities at a four-momentum transfer $Q^2<~0.5\hspace{0.5em}{\mathrm{GeV}}^2.$ The dispersive integrals are calculated using a state-of-the-art pion photo- and electroproduction analysis. The dispersion formalism provides a new tool to analyze VCS experiments above pion threshold, thus increasing the sensitivity to the generalized polarizabilities of the nucleon.

The reaction $\overrightarrow{p}\overrightarrow{p}\mathrm{ppX}$ was studied at three energies ${(T}_p=1520,$ 1805, and 2100 MeV) and at several angles between $0°$ and $17°$ in the lab. The analyzing powers and differential cross sections of light meson production, $X=\pi ,$ $\eta ,$ and $\omega ,$ were measured. The c.m. angular range varied between $0°$ and $180°$ where the incident energy combined with the experimental acceptance allow both forward and backward kinematical solutions. A theoretical analysis based on s-channel contributions in $2^{+}$ and $1^{-}$ intermediate states was performed. Narrow peaks were looked for, between $\eta$ and $\omega$ meson masses and extracted at 588, 608, 647, 681, and 700 MeV. The evidence for their existence is discussed in accordance with the corresponding number of standard deviations (SD).

Angular distributions of protons emitted from ground and isomeric states in oriented nuclei are calculated. Odd-Z, odd-A proton emitting nuclei are considered in this work. The shape of the angular distributions shows strong dependence with the angular momentum carried away by the proton. They can be used potentially as a spectroscopic tool.

The role of spatial correlations (i.e., the range of clusterization) along with the role of the range of interaction is analyzed in multifragmentation within a quantum molecular dynamics model. We find that the effect of different ranges of clusterization and interactions depends on the physical conditions and excitation energy of the system. The impact of different clusterization ranges is more than marginal in the presence of a momentum dependent interaction which is different than that obtained with a static equation of state.

Starting from the recognition that hadrons are not produced smoothly at phase transition, the fluctuation of spatial patterns is investigated by finding a measure of the voids that exhibits scaling behavior. The Ising model is used to simulate a crossover in quark-hadron phase transition. A threshold in hadron density is used to define a void. The dependence of the scaling exponents on that threshold is found to provide useful information on some properties of the hadronization process. The complication in heavy-ion collision introduces the possibility of configuration mixing, which can also be studied in this approach. Numerical criteria on the scaling exponents have been found that can be used to discriminate phase-transition processes from other hadronization processes having nothing to do with critical phenomena.

We describe an experiment that has set new limits on the time reversal invariance violating D coefficient in neutron $\beta$ decay. The emiT experiment measured the angular correlation $〈\mathbf{J}〉\cdot ({\mathbf{p}}_e\times {\mathbf{p}}_p)$ using an octagonal symmetry that optimizes electron-proton coincidence rates. The result is $D=[-0.6\pm 1.2(\mathrm{stat})\pm 0.5(\mathrm{syst}\left)\right]\times {10}^{-3}.$ This improves constraints on the phase of $g_A{/g}_V$ and limits contributions to T violation due to leptoquarks. This paper presents details of the experiment, data analysis, and the investigation of systematic effects.

The data of direct single-photon measurements of the WA98 Collaboration in the reaction $\mathrm{Pb}(158A$ GeV) + Pb are analyzed within a thermal model with a minimum number of parameters adjusted to the dilepton data obtained by the CERES and NA50 Collaborations in the reactions $\mathrm{Pb}(158A$ GeV) + Au, Pb. The agreement of our model with the WA98 data points to a unique large thermal source emitting electromagnetic radiation is observable in both the real and virtual photon channels.

A chemically selective laser ion source has been applied in a decay study of the very neutron-rich isotopes ${}^{131}\mathrm{Cd}$ and ${}^{132}\mathrm{Cd}$ at CERN/ISOLDE. For the ${\beta }^{-}$ decay of the $N=83\mathrm{}$ nuclide ${}^{131}\mathrm{Cd}$ a surprisingly short half-life of $(68\mathrm{}\pm 3)$ ms and a weak delayed-neutron branch of $P_n=(3.5\mathrm{}\pm 1.0)\%$ were observed. For the $N=84\mathrm{}$ nuclide ${}^{132}\mathrm{Cd}$ a half-life of $(97\mathrm{}\pm 10)$ ms and a $P_n$ value of $(60\mathrm{}\pm 15)\%$ were obtained. Schematic features of both decay schemes are developed. We find that our new data are not reproduced by current global models used for ab initio calculations of $\beta$-decay properties without significant changes.