We have investigated the final-state spectrum of ${\mathrm{HeT}}^{+}$ and ${\mathrm{HeH}}^{+}$ following $\beta$ decay of ${\mathrm{T}}_2$ or TH. For the electronically bound-state part of the spectrum the effects of a corrected recoil, improved potential curves for the excited states, nonadiabatic effects, and excitations of the initial molecular state have been investigated. We also discuss the feasibility of various experimental methods to verify the theoretical final-state spectrum.

Using phosphate glass detectors PKS-50, we have searched for possible emission of heavy clusters in the decay of ${}^{249}\mathrm{Cf}$ with the aim of confirming the result obtained from a recent $\gamma$ ray spectrometry experiment. After a 20-day exposure to a 7.4 MBq activity ${}^{249}\mathrm{Cf}$ source of $37.5\hspace{0.5em}{\mathrm{cm}}^2$ PKS-50 glasses covered with polymide foils to stop fission fragments, no ions with $17<~Z<~21$ were detected. We could deduce an upper limit of the branching ratio (90% C.L.) $b<~1.5\times {10}^{-12}$ and a partial half-life $T_{1/2}>~7.4\times {10}^{21}\hspace{0.5em}\mathrm{s}.$ According to calculations performed on the basis of the preformed cluster model there seems to be very little chance that such an exotic decay might be detected, at least in the next few years.

$Q$ invariants are quantities, obtained from complete sets of $B\left(E2\mathrm{}\right)\mathrm{}$ values, that give direct physical insight into the structure of a nucleus. Greatly simplified expressions for Q invariants and for quadrupole moments are tested in the framework of the geometric collective model (GCM) by analyzing the quadrupole phonon structure of nuclei. Empirical axial asymmetry $\left(\gamma \right)$ values extracted from one of the Q invariants are compared to values obtained with a rigid triaxial model. These results demonstrate the usefulness of Q invariants, especially in exotic nuclei where only sparse data will be available.

Analytical expressions of the one- and two-body terms in the cluster expansion of the charge form factors and densities of the $s-p$ and $s-d$ shell nuclei with $N=Z$ are derived. They depend on the harmonic oscillator parameter b and the parameter $\beta$ which originates from the Jastrow correlation function. These expressions are used for the systematic study of the effect of short range correlations on the form factors and densities and of the mass dependence of the parameters b and $\beta$. These parameters have been determined by fit to the experimental charge form factors. The inclusion of the correlations reproduces the experimental charge form factors at the high momentum transfers $(q>~2\hspace{0.5em}{\mathrm{fm}}^{-1})$. It is found that while the parameter $\beta$ is almost constant for the closed shell nuclei ${}^4\mathrm{He},$ ${}^{16}\mathrm{O}$, and ${}^{40}\mathrm{Ca}$, its values are larger (less correlated systems) for the open shell nuclei, indicating a shell effect in the closed shell nuclei.

We calculate saturation curves for strange hadron matter using recently constructed baryon-baryon potentials which are constrained by SU(3) symmetry. All possible interaction channels within the baryon octet (consisting of $N,\Lambda ,\Sigma$, and $\Xi )$ are considered. It is found that a small $\Lambda$ fraction in nuclear matter slightly increases binding, but that larger fractions $\mathrm{}(>10\%)\mathrm{}$ rapidly cause a decrease. Charge-neutral $\{N,\Lambda ,\Xi \}$ systems, with equal densities for nucleons and cascades, are only very weakly bound. The dependence of the binding energies on the strangeness per baryon, $f_s,$ is predicted for various $\{N,\Lambda ,\Xi \}$ and $\{N,\Lambda ,\Sigma ,\Xi \}$ systems. The implications of our results in relativistic heavy-ion collisions and the core of a dense star are discussed. We also discuss the differences between our results and previous hadron matter calculations.

In two complementary measurements, a cubelike array of 6 Euroball-Cluster germanium detectors and a total-absorption $\gamma$-spectrometer were used to investigate the $\beta$ decay of ${}^{97}\mathrm{Ag}$, a three proton-hole nucleus with respect to the ${}^{100}\mathrm{Sn}$ core. The half-life and $Q_{\mathrm{EC}}$ value of the decay of the ${9/2}^{+}$ ground state of ${}^{97}\mathrm{Ag}$ were determined to be 25.9(4) s and 6.98(11) MeV, respectively. A total of 603 $\gamma$ rays (578 new) was observed, and 151 levels (132 new) in ${}^{97}\mathrm{Pd}$ have been identified. An interesting $\beta$-delayed $\gamma$ cascade was observed, which comprises 6 $\gamma$-transitions with a deexcitation pattern involving an initial increase of the level spin. The Gamow-Teller (GT) $\beta$-decay strength distributions from the two measurements reveal a large GT resonance around 4 MeV with a width of about 1.8 MeV. The hindrance factor for the total GT strength, summed from the ground state up to 6 MeV excitation energy in ${}^{97}\mathrm{Pd}$, amounts to 4.3(6) with reference to a shell-model prediction. This factor is discussed in comparison with a core polarization and a Monte Carlo shell-model calculation.

The quadrupole interaction of the $7^{-}$ 2454 keV isomeric state $\mathrm{in}{\hspace{0.5em}}^{130}\mathrm{Ce}$ with the electric field gradient of a polycrystalline metallic tin lattice has been investigated by the time-differential perturbed angular distribution method. A quadrupole coupling constant ${\nu }_Q=71\mathrm{}\left(4\right)\mathrm{}\hspace{0.5em}\mathrm{MHz}$ has been determined, leading to a quadrupole moment value $|Q|=1.77\mathrm{}\left(21\right)\mathrm{}\hspace{0.5em}e\mathrm{b}$. The result gives support to the description of the $7^{-}$ isomeric state by a high-$K$ two-neutron configuration involving Nilsson orbitals from the $h_{11/2}$ and $g_{7/2}$ states. A mean value of $K=6.0\mathrm{}\left(2\right)\mathrm{}$ has been deduced.

${}^{12}\mathrm{C}{(}^7\mathrm{Li},\alpha )$ angular distributions have been obtained for 16 states in ${}^{15}\mathrm{N}$ at ${E(}^7\mathrm{Li})=52.5\mathrm{}\hspace{0.5em}\mathrm{MeV}$. Also, ${}^{12}\mathrm{C}{(}^6\mathrm{Li}\to {,}^3\mathrm{He})$ angular distributions and vector analyzing powers have been measured at ${E(}^6\mathrm{Li}\to )=50\mathrm{}\hspace{0.5em}\mathrm{MeV}$. Finite-range distorted-wave Born-approximation (FRDWBA) triton cluster transfer calculations are able to describe the ${(}^7\mathrm{Li},\alpha )$ data for transfer to states with known $J^{\pi }$ values. Comparison with known levels in ${}^{19}\mathrm{F}$ suggests that the ${}^{12}\mathrm{C}{(}^7\mathrm{Li},\alpha )$ reaction selectively populates negative parity states. FRDWBA calculations support this idea. Several previously suggested $J^{\pi }$ levels are confirmed and new $J^{\pi }$ values are proposed for six other levels. The previously observed ${(}^6\mathrm{Li}\to {,}^3\mathrm{He})\hspace{0.5em}J$ dependence has been used along with coupled-channel Born-approximation calculations to confirm the $J^{\pi }$ values for states in ${}^{15}\mathrm{N}$.

Using the former results and analyzing the quantitative discrepancies between the experimental data and present theories concerning the projectile fragmentation process we propose an improvement on Goldhaber formula. We want therefore to sustain the idea that the projectile fragmentation process is not as fast as it was supposed to be from the very beginning. The process would be governed by the distribution of nucleon momenta in the projectile shortly after the collision occurred. We used in our analysis protons from the ${}^4\mathrm{He}$ fragmentation when colliding ${}^7\mathrm{Li}$ target at 4.5 $\mathrm{GeV}/c$ per nucleon incident momentum, protons detected by the 2 m streamer chamber from SKM 200 spectrometer as well as ${}^{40}\mathrm{Ar}\hspace{0.5em}{(E}_{\mathrm{inc}}=213\mathrm{}\mathrm{\hspace{0.5em}}\mathrm{M}\mathrm{e}\mathrm{V}/\mathrm{n}\mathrm{u}\mathrm{c}\mathrm{l}\mathrm{e}\mathrm{o}\mathrm{n}{)+}^{12}\mathrm{C}$ data used in previous papers. Our purpose was to demonstrate that in order to proceed in analyzing the projectile fragmentation process at intermediate and high energies one has to take into account the dependence of ${\sigma }_0$ on the apparent temperature of projectile nucleus soon after the collision took place. The generalized Bertsch correction for all light up to medium projectile nuclei and fragments is used and the total number of spatial correlations between identical nucleons (in the same state of spin and isospin) having anticorrelated momenta is evaluated. Considering all those criteria as well as the projectile excitation hypothesis, apparent temperature values reasonably close to the separation energies of the considered fragments per number of fragments were found.

The effects of long range absorption on the distribution of fusion barriers are discussed under eigenchannel approximations. It is shown that due to channel coupling effects, the upper fusion barrier cannot be extracted unambiguously using any coupled channel codes based on optical model approaches.

The electromagnetic form factors of the nucleon have been calculated in a chiral constituent-quark model. The nucleon wave functions are obtained by solving a Schrödinger-type equation for a semirelativistic Hamiltonian with an effective interaction derived from the exchange of mesons belonging to the pseudoscalar octet and singlet and a linear confinement potential. The charge-density current operator has been constructed consistently with the model Hamiltonian in order to preserve gauge invariance and to satisfy the continuity equation.

We consider the Dirac equation for a finite-size neutron in an external electric field. We explicitly incorporate Dirac-Pauli form factors into the Dirac equation. After a nonrelativistic reduction, the Darwin-Foldy term is cancelled by a contribution from the Dirac form factor, so that the only coefficient of the external field charge density is ${\mathrm{}(e/6\mathrm{})r}_{\mathrm{En}}^2$, i.e., the root mean square radius associated with the electric Sachs form factor. Our result is similar to a recent result of Isgur, and reconciles two apparently conflicting viewpoints about the use of the Dirac equation for the description of nucleons.

We introduce a transport approach which combines partonic and hadronic degrees of freedom on an equal footing and discuss the resulting reaction dynamics. The initial parton dynamics is modeled in the framework of the parton cascade model, hadronization is performed via a cluster hadronization model and configuration space coalescence, and the hadronic phase is described by a microscopic hadronic transport approach. The resulting reaction dynamics indicate a strong influence of hadronic rescattering on the space-time pattern of hadronic freeze-out and on the shape of transverse mass spectra. Freeze-out times and transverse radii increase by factors of 2–3 depending on the hadron species.

We analyze the hadronic freeze-out in ultrarelativistic heavy-ion collisions at Relativistic Heavy Ion Collider (RHIC) in a transport approach that combines hydrodynamics for the early, dense, deconfined stage of the reaction with a microscopic nonequilibrium model for the later hadronic stage at which the hydrodynamic equilibrium assumptions are not valid. With this ansatz we are able to self-consistently calculate the freeze-out of the system and determine space-time hypersurfaces for individual hadron species. The space-time domains of the freeze-out for several hadron species are found to be actually four dimensional, and differ drastically for the individual hadrons species. Freeze-out radii distributions are similar in width for most hadron species, even though the ${\Omega }^{-}$ is found to be emitted rather close to the phase boundary and shows the smallest freeze-out radii and times among all baryon species. The total lifetime of the system does not change by more than 10% when going from CERN Super Proton Synchrotron to RHIC energies.

$K^{+}$-nucleus cross sections are consistently above those computed using free-space $K^{+}$-nucleon interactions. Many influences of the nucleon medium have been invoked to explain this, but the present analysis uses $K^{+}$-nuclear data to infer the size of the repulsive hard core radius between the $K^{+}$ and nucleons within nuclei by altering a single parameter, the average S-wave phase shift. The resulting hard core radii, larger than seen in free space, increase with nuclear densities.

$K^{-}$ atomic data are used to test several models of the $K^{-}$ nucleus interaction. The $t\left(\rho \right)\rho$ optical potential, due to coupled channel models incorporating the $\Lambda \mathrm{}\left(1405\right)\mathrm{}$ dynamics, fails to reproduce these data. A standard relativistic mean field (RMF) potential, disregarding the $\Lambda \mathrm{}\left(1405\right)\mathrm{}$ dynamics at low densities, also fails. The only successful model is a hybrid of a theoretically motivated RMF approach in the nuclear interior and a completely phenomenological density dependent potential, which respects the low density theorem in the nuclear surface region. This best-fit $K^{-}$ optical potential is found to be strongly attractive, with a depth of $180\pm 20\hspace{0.5em}\mathrm{MeV}$ at the nuclear interior, in agreement with previous phenomenological analyses.

Features of particle emission and critical point behavior are investigated as functions of the isospin of disassembling sources and temperature at a moderate freeze-out density for medium-size Xe isotopes in the framework of the isospin-dependent lattice gas model. Multiplicities of emitted light particles, isotopic, and isobaric ratios of light particles show the strong dependence on the isospin of the dissociation source, but double ratios of light isotope pairs and the critical temperature determined by the extreme values of some critical observables are insensitive to the isospin of the systems. Values of the power law parameter of cluster mass distribution, mean multiplicity of intermediate mass fragments (IMF), information entropy, and Campi’s second moment also show a minor dependence on the isospin of Xe isotopes at the critical point. In addition, the slopes of the average multiplicities of the neutrons ${(N}_n),$ protons ${(N}_p),$ charged particles ${(N}_{\mathrm{CP}}),$ and IMFs ${(N}_{\mathrm{IMF}}),$ slopes of the largest fragment mass number ${(A}_{\max }),$ and the excitation energy per nucleon of the disassembling source ${(E}^{*}/A)$ to temperature are investigated as well as variances of the distributions of $N_n,$ $N_p,$ $N_{\mathrm{CP}},$ $N_{\mathrm{IMF}},$ $A_{\max },$ and $E^{*}/A.\mathrm{}$ It is found that they can be taken as additional judgements to the critical phenomena.

A relativistic description of pion-nucleon scattering based on the four-dimensional Bethe-Salpeter equation is presented. The kernel of the equation consists of s- and u-channel nucleon and $\Delta \mathrm{}\left(1232\right)\mathrm{}$ pole diagrams, as well as $\rho$ and $\sigma$ exchange in the t channel. The Bethe-Salpeter equation is solved by means of a Wick rotation, and good fits are obtained to the s- and p-wave $\pi N$ phase shifts up to 360 MeV pion laboratory energy. The coupling constants determined by the fits are consistent with the commonly accepted values in the literature.

The dispersion relation and damping rate of longitudinal color plasmons in finite strange quark matter (strangelets) are evaluated in the limits of weak coupling, low temperature, and long wavelength. The property of the QCD vacuum surrounding a strangelet makes the frequency of the plasmons nearly the same as the color plasma frequency of bulk matter. The plasmons are damped by their coupling with individual excitations of particle-hole pairs of quarks, of which the energy levels are discretized by the boundary. For strangelets of macroscopic size, the lifetime of the plasmons is found to be proportional to the size, as in the case of the usual plasma oscillations in metal nanoparticles.

The isospin dependence of the real part of the single-particle potential of a $\Sigma$ hyperon in nuclear matter, $V_{\Sigma }$ is investigated. The isospin-dependent part $V_1$ of $V_{\Sigma }$ is expressed in terms of an effective $\Sigma N$ interaction in nuclear matter, which depends on proton and neutron densities. With suitable approximations numerical results for $V_1$ are obtained for four models of the Nijmegen baryon-baryon interaction. A comparison with recent ${(K}^{-},{\pi }^{\pm })$ experiments favors model F as a realistic representation of the $\Sigma N$ interaction.