A level scheme is presented for ${}_{53}^{111}\mathrm{I},$ populated by the ${}^{58}\mathrm{Ni}{(}^{58}\mathrm{Ni},\alpha p)$ reaction. A backed-target experiment, at a low beam energy of 210 MeV, was performed using the JUROSPHERE spectrometer, while a thin-target experiment at 250 MeV was performed using the GAMMASPHERE spectrometer in conjunction with the MICROBALL charged-particle detector array. The new level scheme fits well the systematics of light iodine nuclei and provides evidence for a terminating band at the highest spins. Low-lying transitions previously assigned to ${}^{111}\mathrm{I}$ could not be confirmed.

This experiment has been done with a view to studying complete and incomplete fusion in heavy-ion-induced reactions. Excitation functions for several reactions induced by ${}^{12}{\mathrm{C}}^{5+}$ ions on ${}^{165}\mathrm{Ho}$ at incident energies from 55 to 80 MeV have been measured using the activation technique. The analysis of the data has been done using the codes ALICE-91 and CASCADE. The parameter $F_{\theta },$ the ratio of actual moment of inertia to the rigid-body value, has been found to play an important role in the calculations done by the code CASCADE. Significant contributions from both the complete and the incomplete fusion channels have been observed. Further, in the case of the reaction $(\mathrm{C},p3n)$ considerable contribution from the decay of higher charge isobar precursor has been observed.

We estimate the cross sections for the production of resonances, pion pairs, and a central cluster of hadrons in peripheral heavy-ion collisions through two-photon and double-pomeron exchange, at energies that will be available at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). The effect of the impact parameter in the diffractive reactions is introduced, and by imposing the condition for realistic peripheral collisions we verify that in the case of very heavy ions the pomeron-pomeron contribution is indeed smaller than the electromagnetic one. However, they give a non-negligible background in the collision of light ions. This diffractive background will be more important at RHIC than at LHC.

We report on measurements by the E864 experiment at the BNL-AGS of the yields of light nuclei in collisions of ${}^{197}\mathrm{Au}$ with beam momentum of $11.5A\mathrm{GeV}/c$ on targets of ${}^{208}\mathrm{Pb}$ and ${}^{197}\mathrm{Pt}.$ The yields are reported for nuclei with baryon number $A=1\mathrm{}$ up to $A=7,$ and typically cover a rapidity range from $y_{\mathrm{c}.\mathrm{m}.\mathrm{}}$ to $y_{\mathrm{c}.\mathrm{m}.\mathrm{}}+1\mathrm{}$ and a transverse momentum range of approximately $0.1<~p_T/A<~0.5\mathrm{GeV}/c.\mathrm{}$ We calculate coalescence scale factors $B_A$ from which we extract model-dependent source dimensions and collective flow velocities. We also examine the dependences of the yields on baryon number, spin, and isospin of the produced nuclei.

Quantization procedure of the axially symmetric $B=2\mathrm{}$ solution in the chiral quark soliton model is proposed. The method is based on the $\mathrm{SU}\left(2\right)\mathrm{}$ collective coordinate method. Adiabatic isorotation as well as spatial rotation are considered. The calculated moment of inertia is in qualitative agreement with the results of the Skyrme model. The mass spectrum of the two-baryon systems are shown. We also estimate the “binding energies” of the dibaryon states, which are consistent with those of the other effective quark potential models.

We propose a description of cluster states in nuclei in terms of representations of unitary algebras $\mathrm{U}(\nu +1),$ where $\nu$ is the number of space degrees of freedom. Within this framework, a variety of situations including both vibrational and rotational spectra, soft and rigid configurations, identical and nonidentical constituents can be described. As an example, we show how the method can be used to study $\alpha$ clustering configurations in ${}^{12}\mathrm{C}\mathrm{}$ with point group symmetry ${\mathcal{D}}_{3h}.$

The recent observation of low-lying collective bands built on $0^{+}$ intruder states in the neutron-deficient Pb region is discussed within the context of two-particle–two-hole and four-particle–four-hole proton excitations across the $Z=82\mathrm{}$ proton shell closure.

The strength distribution of the giant monopole resonance in ${}^{58}\mathrm{Ni}$ has been measured from $E_x=10\mathrm{}$ to 35 MeV using small-angle scattering of 240-MeV α particles. $E0\mathrm{}$ strength corresponding to ${74}_{-12}^{+22\mathrm{}}\%$ of the $E0\mathrm{}$ EWSR was found between $E_x=12.0\mathrm{}$ and 31.1 MeV with a centroid of ${20.30}_{-0.14}^{+1.69\mathrm{}}\mathrm{MeV}.$

The cross sections for elastic scattering of the weakly bound ${}^9\mathrm{Be}$ on ${}^{209}\mathrm{Bi}$ around the Coulomb barrier have been measured with $\sim 5\%$ absolute accuracy from 40 to 48 MeV. The potential obtained from an optical model analysis has an unusual behavior. At the strong absorption radius the imaginary (absorptive) potential is increasing (rather than decreasing) with decreasing energy, as would be consistent with a long range polarization potential arising mainly from couplings to breakup channels. The real part, on the other hand, displays a strong attractive polarization contribution with the maximum at the barrier, as would be normally expected from a polarization contribution arising from strong couplings. The inelastic multiplet in ${}^{209}\mathrm{Bi}$ of collective nature around 2.6 MeV, originating from the coupling ${[}^{208}\mathrm{Pb}{(3\mathrm{}}^{-})\otimes h_{{9/2}^{-}}{]}_{J^{\pi }},$ was seen only at 48 MeV. The total multiplet cross section is well reproduced by coupled channel calculations with the potential obtained from the optical analysis and the experimental $B\left(E3\mathrm{}\right)\mathrm{}$ strengths of the ${}^{209}\mathrm{Bi}$ multiplet levels.

The first measurement of the ${}^2\mathrm{H}(\overrightarrow{\gamma },n)p$ analyzing power near threshold has been performed using the High-Intensity Gamma-ray Source (HIGS) at the Duke Free-Electron Laser Laboratory. A 3.58 MeV $\gamma$-ray beam having an energy resolution of $2.5\%$ and $100\%$ linear polarization was incident on an active ${\mathrm{C}}_6{\mathrm{D}}_{12}$ target. Outgoing neutrons were detected parallel and perpendicular to the plane of $\gamma$-ray polarization at a lab angle of 150°. The experimentally determined analyzing power provides a sensitive measurement of the relative $E1\mathrm{}$ and $M1\mathrm{}$ contributions to the total cross section.

First calculations for spin-dependent observables of the reactions $p\overrightarrow{p}\mathrm{pp}{\pi }^0,$ $p\overrightarrow{p}\mathrm{pn}{\pi }^{+},$ and $p\overrightarrow{p}d{\pi }^{+}$ near threshold are presented, employing the Jülich model for pion production. The influence of resonant [via the excitation of the $\Delta \mathrm{}\left(1232\right)\mathrm{}]$ and nonresonant p-wave pion production mechanisms on these observables is examined. For the reactions $p\overrightarrow{p}\mathrm{pn}{\pi }^{+}$ and $p\overrightarrow{p}d{\pi }^{+}$ nice agreement of our predictions with the presently available data on spin correlation coefficents is observed whereas for $p\overrightarrow{p}\mathrm{pp}{\pi }^0$ the description of the data is less satisfying.

We test the presence of pion-nucleon isoscalar off-shell effects in the $p\overrightarrow{d}{\pi }^{+}t$ reaction around the threshold region. We find that these effects significantly modify the production cross section and that they may provide the missing strength needed to reproduce the data at threshold.

The energy level schemes and gyromagnetic factors of the excited states of a series of transitional nuclei, ${}^{146-150}\mathrm{Nd},$ Gd, Sm, Dy, and ${}^{156}\mathrm{Nd}$ have been studied within the framework of cranked Hartree-Fock-Bogoliubov formalism with the inclusion of hexadecapole deformation in the cranking Hamiltonian. The calculated results are discussed with the available experimental findings on these transitional nuclei. It has been observed that the Routhians of these transitional nuclei distinctly indicate deformation structures that can be explained on the basis of the present theoretical model scheme.

We investigated the nucleus ${}^{195}\mathrm{Pt}$ via $\mathrm{}(p,d)\mathrm{}$ and polarized $(\overrightarrow{d},t)$ one neutron pickup reactions. Rather complete spectra are obtained resulting in new spin assignments of 42 states in ${}^{195}\mathrm{Pt}$ and in information about spectroscopic transfer strengths for each level up to an excitation energy of 1450 keV. A $U(6/12)\mathrm{}$ supersymmetric level scheme, describing with its five parameters the O(6) spectrum of ${}^{194}\mathrm{Pt}$ and the negative parity states of ${}^{195}\mathrm{Pt},$ reproduces these spectra. For the lower part of the spectrum also the transfer strengths, calculated with a semimicroscopic transfer operator, agree well with the experiment. The reproduction of the very rich data set improves and extends the evidence that the low-energy spectrum, which results from the coupling of the unpaired neutron in a few, specific orbits to the O(6) core, is determined in a rather complete way by supersymmetry.

High-spin states have been investigated in the $N=Z=22\mathrm{}$ nucleus ${}^{44}\mathrm{Ti}.$ A newly observed set of states with $J^{\pi }{=6\mathrm{}}^{+},$ $8^{+},$ ${10}^{+},$ and ${12}^{+}$ are assigned to be members of a band built upon an excited $0^{+}$ state. This band displays rotational-like level spacings, with a near-linear $J(J+1\mathrm{})\mathrm{}$ dependence. A third set of $J^{\pi }{=8\mathrm{}}^{+},$ ${10}^{+},$ and ${12}^{+}$ states have also been tentatively assigned and a negative-parity intruder band has been extended to $J^{\pi }{=13\mathrm{}}^{-}.$ Comparisons with $\mathrm{df}$-shell model calculations show a good agreement for both energy levels and branching ratios. These calculations indicate that the excited $0^{+}$ band is dominated by a mixture of $8p–4h$ and $6p–2h$ configurations relative to ${}^{40}\mathrm{Ca}.$

The $\alpha {+}^{12}\mathrm{C}$ $d$ phase shift and the ${}^{12}\mathrm{C}(\alpha ,\gamma {)}^{16}\mathrm{O}$ $E2\mathrm{}$ $S$ factor are analyzed in the $R$-matrix theory. A new method is proposed to link experimental and calculated parameters within the $R$-matrix formalism. We show that interference patterns in the phase shift near 3 MeV are very helpful to constrain the parameter set. Starting from this analysis, we fit the ${}^{12}\mathrm{C}(\alpha ,\gamma {)}^{16}\mathrm{O}$ $E2\mathrm{}$ $S$ factor, and find low-energy values larger than currently accepted. Different interference patterns are found, but do not appear to affect the astrophysical energies. Consequently, direct measurements at low energies are necessary for astrophysical applications.

We have performed a measurement of the cross section for the ${}^4\mathrm{He}(\gamma ,dd)$ reaction with photon energies between 150 and 250 MeV. Both reaction particles were detected in coincidence. We obtained absolute cross sections at six angles and two energy bins (150–190 MeV and 190–250 MeV). A Legendre polynomial fit to the angular distribution shows a ${\sin }^2\theta$ distribution which suggests the isospin-forbidden $E1\mathrm{}$ transition. However, a transition matrix element (TME) analysis using only strictly allowed transitions shows that the angular distribution can be described by just two TMEs: $E2\mathrm{}$ s- and d-wave absorption on the D state of ${}^4\mathrm{He}.$ We performed an inverse direct-capture calculation in order to determine if the D state could contribute to such a high degree to the cross section. This calculation indicates that 90% of the cross section arises from absorption on the D state but fails to reproduce the observed ${\sin }^2\theta$ angular distribution.

I consider the dissociation of ${\rm Y}$ due to absorption of a thermal gluon. I discuss the dissociation rate in terms of the energy density, the number density, and the temperature of the quark-gluon plasma. I compare this to the effect due to screening.

The structure of a new dibaryon $(\Omega \Omega {)}_{0^{+}}$ is studied theoretically in the framework of the chiral SU(3) quark model by solving a resonating group method equation. The binding energy of this dibaryon is predicted to be around 100 MeV, the mean-square root of the distance between two Ω’s is 0.84 fm, and the preliminary estimated mean lifetime is about two times that of the free $\Omega$’s. All these interesting properties, as well as the two negative charge units it carries, could make it easily identifiable experimentally in the heavy ion collision process. The production probability of this new dibaryon in a 158 GeV $\mathrm{Pb}+\mathrm{Pb}$ collision is estimated using the thermal model. The rate is of the order of ${10}^{-6}$ to ${10}^{-5}$ per event. It is expected that, with the increase of the temperature, the production rate will also be increased.

We derive the light cone QCD sum rule for the $\eta \mathrm{NN}$ coupling constant $g_{\eta \mathrm{NN}}.$ The contribution from the excited states and the continuum is subtracted cleanly through the double Borel transform with respect to the two external momenta, $p_1^2{,p}_2^2=(p-{q)}^2.$ Our result is ${\alpha }_{\eta \mathrm{NN}}=(0.3\mathrm{}\pm 0.15),$ which favors small values used in the literature.