The ${}^{32}\mathrm{S}(d,{}^2\mathrm{He}){}^{32}\mathrm{P}$ charge-exchange reaction has been studied at forward angles and at an incident energy of $E_d=170\mathrm{MeV}$. The two protons in the ${}^{1}S_0\left(pp\right)$ state (indicated as ${}^2\mathrm{He}$) were both momentum analyzed and detected by the same spectrometer and detector. High resolution ${}^2\mathrm{He}$ spectra have been obtained allowing identification of many levels in the residual nucleus with high precision. The $(d,{}^2\mathrm{He})$ reaction selectively excites spin-isospin-flip transitions, and at vanishing momentum transfer these are largely governed by the Gamow-Teller transition operator for the ${\beta }^{+}$ direction. In the case of the self-conjugate nucleus ${}^{32}\mathrm{S}$, the $(d,{}^2\mathrm{He})$ probe is calibrated against the elementary $(p,n)$ probe going into the mirror ${\beta }^{-}$ direction. The deduced results are compared with those obtained from $(p,p^{\prime })$ and $(e,e^{\prime })$ reactions, which excite the same levels in the isospin multiplet. Angular distributions of cross sections for the $(d,{}^2\mathrm{He})$ reaction are presented and compared with DWBA calculations. A level-by-level comparison with shell-model calculations using the USD interaction has been performed, and the structure of the $l$-forbidden ground state transition is discussed. From the comparison with $(p,p^{\prime })$, $(e,e^{\prime })$, and $(p,n)$ data the isospin-analog $J^{\pi }=1^{+}$ levels in the triplet of the $A=32$ nuclei are deduced.

A new pixel-structure detector array with a large solid angle coverage has been used for the first time to study the elastic scattering of exotic ${}^{17}\mathrm{F}$ nuclei from a ${}^{208}\mathrm{Pb}$ target at $90.4\mathrm{MeV}$. The experimental data have been analyzed in the framework of the optical model potential and the real and imaginary strong absorption radii have been evaluated. These quantities have been compared with those obtained for the system ${}^{19}\mathrm{F}+{}^{208}\mathrm{Pb}$ at the same energy in the center of mass frame. The ${}^{17}\mathrm{F}+{}^{208}\mathrm{Pb}$ reaction cross section is more similar to those of the systems ${}^{16,17}\mathrm{O}+{}^{208}\mathrm{Pb}$ rather than to the one of the system ${}^{19}\mathrm{F}+{}^{208}\mathrm{Pb}$ at similar energies: this indicates that in the energy range around the Coulomb barrier the breakup channel is still weak. The exclusive breakup cross section ${}^{17}\mathrm{F}\to {}^{16}\mathrm{O}+p$ has been measured for the first time at energy below the Coulomb barrier.

A prescription to incorporate the effects of nuclear flow on the process of multifragmentation of hot nuclei is proposed in an analytically solvable canonical model. Flow is simulated by the action of an effective negative external pressure. It favors sharpening the signatures of liquid-gas phase transition in finite nuclei with increased multiplicity and a lowered phase transition temperature.

We calculate the nucleon parameters in nuclear matter using the QCD sum rules approach in gas approximation. Terms up to $1∕q^2$ in the operator product expansion $\left(\mathrm{OPE}\right)$ are taken into account. The higher moments of the nucleon structure functions are included. The complete set of the nucleon expectation values of the four-quark operators is employed. Earlier the lack of information on these values has been the main obstacle for the further development of the approach. We show that the values of the four-quark condensates are consistent with the assumptions about the convergence of the $\mathrm{OPE}$. Inclusion of these condensates and of the nonlocality of the vector condensate are important for the calculation of the nucleon parameters. The nucleon vector self-energy ${\Sigma }_v$ and the nucleon effective mass $m^{*}$ are expressed in terms of the in-medium values of QCD condensates. The numerical results for these parameters at the saturation value of the density agree with those obtained by the methods of nuclear physics.

The long-lived radioactive nuclide ${}^{22}\mathrm{Na}$ $(t_{1∕2}=2.6\mathrm{yr})$ is an astronomical observable for understanding the physical processes of oxygen-neon novae. Yields of ${}^{22}\mathrm{Na}$ in these events are sensitive to the unknown total rate of the ${}^{21}\mathrm{Na}(p,\gamma ){}^{22}\mathrm{Mg}$ reaction. Using a high intensity ${}^{21}\mathrm{Na}$ beam at the $\mathrm{TRIUMF}\text{−}\mathrm{ISAC}$ facility, the strengths of seven resonances in ${}^{22}\mathrm{Mg}$, of potential astrophysical importance, have been directly measured at center of mass energies from $E_{\mathrm{c.m.}}=200$ to $1103\mathrm{keV}$. We report the results obtained for these resonances and their respective contributions to the ${}^{21}\mathrm{Na}(p,\gamma ){}^{22}\mathrm{Mg}$ rate in novae and x-ray bursts, and their impact on ${}^{22}\mathrm{Na}$ production in novae.

The properties of even-even nuclei with $30⩽\mathrm{Z}⩽82$, $\mathrm{A}⩾60$ have been examined to find examples displaying the characteristics of $\mathrm{E}\left(5\right)$ critical-point behavior for the shape transition from a spherical vibrator to a triaxially soft rotor. On the basis of the known experimental state energies and $\mathrm{E}2$ transition strengths, the best candidates that were identified are ${}^{102}\mathrm{Pd}$, ${}^{106,108}\mathrm{Cd}$, ${}^{124}\mathrm{Te}$, ${}^{128}\mathrm{Xe}$, and ${}^{134}\mathrm{Ba}$. The closest agreement between experimental data and the predictions of $\mathrm{E}\left(5\right)$ is for ${}^{128}\mathrm{Xe}$ and for the previously suggested example of ${}^{134}\mathrm{Ba}$. It is proposed that ${}^{128}\mathrm{Xe}$ may be a new example of a nucleus at the $\mathrm{E}\left(5\right)$ critical point.

The excited levels of ${}^{126}\mathrm{Te}$ have been studied using the $\left(n,n^{\prime }\gamma \right)$ reaction. Excitation functions, $\gamma \gamma$ coincidences, angular distributions, and Doppler shifts were measured for $\gamma$ rays from levels up to an excitation energy of $3.2\mathrm{MeV}$; multipole-mixing and branching ratios and transition rates were deduced. Experimental values of electromagnetic transition rates were compared with the anharmonic vibrator model, the general collective model, the neutron-proton interacting boson model with intruder mixing, and particle-core coupling model calculations. No advantage is found in using an intruder description for the low-spin states of ${}^{126}\mathrm{Te}$. All models used reproduce some features of the level scheme and many transition rates, but the particle-core coupling model was found to have better overall success describing the observed properties of this nucleus.

The equation of state for quark matter is derived for a nonlocal, chiral quark model within the mean field approximation. Special emphasis is on the occurrence of a diquark condensate which signals a phase transition to color superconductivity and its effects on the equation of state. We present a fit formula for the Bag pressure, which is density dependent in the case when the quark matter is color superconducting. We calculate the quark star configurations by solving the Tolman-Oppenheimer-Volkoff equations and demonstrate the effects of diquark condensation on the stability of hybrid stars for different form factors of the quark interaction.

Four nuclei which are proved to be $2\nu \beta \beta$ emitters (${}^{76}\mathrm{Ge}$, ${}^{82}\mathrm{Se}$, ${}^{150}\mathrm{Nd}$, ${}^{238}\mathrm{U}$), and four suspected, due to the corresponding $Q$-values, to have this property (${}^{148}\mathrm{Nd}$, ${}^{154}\mathrm{Sm}$, ${}^{160}\mathrm{Gd}$, ${}^{232}\mathrm{Th}$), were treated within a proton-neutron quasiparticle random phase approximation $\left(\mathrm{pnQRPA}\right)$ with a projected spherical single particle basis. The advantage of the present procedure over the ones using a deformed Woods-Saxon or Nilsson single particle basis is that the actual $\mathrm{pnQRPA}$ states have a definite angular momentum while all the others provide states having only $K$ as a good quantum number. The model Hamiltonian involves a mean field term yielding the projected single particle states, a pairing interaction for alike nucleons and a dipole-dipole proton-neutron interaction in both the particle-hole $\left(ph\right)$ and particle-particle $\left(pp\right)$ channels. The effect of nuclear deformation on the single beta strength distribution as well as on the double beta Gamow-Teller transition amplitude $\left(M_{\mathrm{GT}}\right)$ is analyzed. The results are compared with the existent data and with the results from a different approach, in terms of the process half-life $T_{1∕2}$. The case of different deformations for mother and daughter nuclei is also presented.

The fusion of two interacting heavy ions traditionally has been interpreted in terms of the penetration of the projectile into the target. Observed rates well below the Coulomb barrier are considerably lower than estimates obtained from penetration factors. One approach in the analysis of the data invokes coupling to nonelastic channels in the scattering as the source of the depletion. Another is to analyze those data in terms of tunneling in semiclassical models, with the observed depletion being taken as evidence of a “friction” under the barrier. A complementary approach is to consider such tunneling in terms of a fully quantal model. We investigate tunneling with both one-dimensional and three-dimensional models in a fully quantal approach to investigate possible sources for such a friction. We find that the observed phenomenon may not be explained by this friction. However, we find that under certain conditions tunneling may be enhanced or diminished by up to $50\%$, which finds analogy with observation, without the invocation of a friction under the barrier.

Fluctuations of the color superconducting gap in hot and dense quark matter are investigated in terms of the phenomenological Ginzburg-Landau approach. Our estimates show that fluctuations of the di-quark gap may strongly affect some of thermodynamic quantities even far below and above the critical temperature. If the critical temperature of the di-quark phase transition were rather high one could expect a manifestation of fluctuations of the di-quark gap in the course of heavy ion collisions.

Recent calculations predict a possible existence of nuclei with tetrahedral symmetry: more precisely, the mean-field Hamiltonians of such nuclei are symmetric with respect to double point-group $T_d^D$. In this paper, we focus on the neutron-rich zirconium isotopes as an example and present realistic mean-field calculations which predict tetrahedral ground-state configurations in ${}^{108,110}\mathrm{Zr}$ and low-lying excited states of tetrahedral symmetry in a number of $N⩽66$ isotopes. The motivations for focusing on these nuclei together with a discussion of the possible experimental signatures of tetrahedral symmetry are also presented.

The neutron deficient $A\sim 90$ nuclei constitute a good testing ground for shell model approaches based on spherical or deformed basis. New experimental data are presented for the ${}^{90}\mathrm{Ru}$ nucleus, as obtained with the reaction ${}^{40}\mathrm{Ca}+{}^{58}\mathrm{Ni}$ at $135\mathrm{MeV}$. The yrast band has been extended to higher spin states and a new band, tentatively assigned as a negative parity band, has been identified. The observed structures are compared with predictions of the projected shell model, which uses a deformed basis. Possibility of the occurrence of low-lying high-$K$ states in this nucleus is discussed.

The quasiparticle-phonon nuclear model extended to finite temperature within the framework of thermofield dynamics is applied to calculate a temperature dependence of the spreading width ${\Gamma }^{\downarrow }$ of a giant dipole resonance. Numerical calculations are made for ${}^{120}\mathrm{Sn}$ and ${}^{208}\mathrm{Pb}$ nuclei. It is found that ${\Gamma }^{\downarrow }$ increases with $T$. The reason for this effect is discussed as well as a relation of the present approach to other ones existing in the literature.

The Monte Carlo multicollisional (MCMC) intranuclear cascade model is used to study photonuclear reactions at intermediate energies $\left(20⩽E_{\gamma }⩽140\mathrm{MeV}\right)$. This version of the code differs from previous versions in the following aspects: (i) the quasideuteron model of photoabsorption is consistently included by taking into account relative momentum correlations of the neutron-proton pair in a relativistic kinematics; (ii) a realistic treatment of the Pauli-blocking mechanism at the initial photoabsorption and at each binary nucleon-nucleon scattering during the cascade process is incorporated throughout the calculations; (iii) a criterion based on energy considerations is required by the end of the cascade. Differently from other transport models used so far, which are based on a randomly generated nuclear ground state with a stochastic treatment of the Pauli blocking, the present model incorporates a shell constrained momentum space of the nucleons which is preserved as the cascade evolves along time. The transition between the pre-equilibrium and evaporation phases is energetically determined, allowing the description of the cascade process without any free parameter, such as some ambiguous stopping time parameters adopted in similar time-structured cascade models. The occupation number distribution after the cascade corresponds to a typical Fermi distribution at a finite nuclear temperature, and the long-standing spurious depletion of the Fermi sphere, usually present in other cascade models, no longer appears. The Pauli-blocking factors are calculated and compared with previous approaches based on Fermi gas level density calculations. The evaporation-fission process of the compound nucleus is described in the framework of a Monte Carlo algorithm. Experimental data of the total photoabsorption cross section and the neutron multiplicities for $\mathrm{Sn}$, $\mathrm{Ce}$, $\mathrm{Ta}$, and $\mathrm{Pb}$ in the $20–140\text{−}\mathrm{MeV}$ range are described fairly well by the present calculations.

Data for pion-single-charge exchange reactions at $750\text{MeV}∕c$ on complex nuclei are analyzed for $y$-scaling, or single scattering quasifree, responses. The angular dependence of the data is used to separate the spin and nonspin isovector responses, with comparisons to electron scattering results.

The $\pi N\to KY$ and $KY\to KY$ reactions are studied using a dynamical coupled-channel model of meson-baryon interactions at energies where the baryon resonances are strongly excited. The channels included are: $\pi N$, $K\Lambda$, and $K\Sigma$. The resonances considered are: $N^{*}\left[S_{11}\left(1650\right),P_{11}\left(1710\right),P_{13}\left(1720\right),D_{13}\left(1700\right)\right]$; ${\Delta }^{*}\left[S_{31}\left(1900\right),P_{31}\left(1910\right),P_{33}\left(1920\right)\right]$; ${\Lambda }^{*}\left[S_{01}\left(1670\right),P_{01}\left(1810\right)\right]$ ${\Sigma }^{*}\left[P_{11}\left(1660\right),D_{13}\left(1670\right)\right]$; and $K^{*}\left(892\right)$. The basic nonresonant $\pi N\to KY$ and $KY\to KY$ transition potentials are derived from effective Lagrangians using a unitary transformation method. The dynamical coupled-channel equations are simplified by parametrizing the $\pi N\to \pi N$ amplitudes in terms of empirical $\pi N$ partial-wave amplitudes and a phenomenological off-shell function. Two models have been constructed. Model $\mathrm{A}$ is built by fixing all coupling constants and resonance parameters using $\mathrm{SU}\left(3\right)$ symmetry, the Particle Data Group values, and results from a constituent quark model. Model $\mathrm{B}$ is obtained by allowing most of the parameters to vary around the values of model $\mathrm{A}$ in fitting the data. Good fits to the available data for ${\pi }^{-}p\to K^0\Lambda ,K^0{\Sigma }^0$ have been achieved. The investigated kinematics region in the center-of-mass frame goes from threshold to $2.5\mathrm{GeV}$. The constructed models can be imbedded into associated dynamical coupled-channel studies of kaon photo- and electroproduction reactions.

Recent experimental data on spacelike and timelike form factors of the nucleon are analyzed in terms of a two-component model with a quarklike intrinsic $q^3$ structure and $q\overline{q}$ pairs.

The $g$ factors of the $9^{-}$ and ${11}^{-}$ yrast states in ${}^{194}\mathrm{Pb}$ and ${}^{196}\mathrm{Pb}$ have been measured using the time-dependent perturbed angular distribution (TDPAD) technique. An analysis of the systematics of the properties of these states in the light Pb isotopes is presented. The results confirm the dominance of the $\nu \left(2f_{5∕2}^{-1}1i_{13∕2}^{-1}\right)$ configuration in the $9^{-}$ isomer. The values for the ${11}^{-}$ isomers are consistent with the $\pi \left(3s_{1∕2}^{-2}1h_{9∕2}1i_{13∕2}\right)$ configuration, but they are smaller than those in the Po isotones. The effects of core excitation and particle-vibration coupling are considered, but these do not lead to a detailed agreement between theory and experiment. A Nilsson approach, however, gives good agreement, providing support for a proposed oblate deformation.

Dibaryon candidates with strangeness $S=-2,-3,-4,-5,-6$ are studied in terms of the extended quark delocalization and color screening model. The results show that there are only a few promising low lying dibaryon states: The $H$ and di-$\Omega$ may be marginally strong interaction stable but model uncertainties are too large to allow any definitive statement. The $SIJ=-3,1∕2,2$ $N\Omega$ state is $62\mathrm{MeV}$ lower than the $N\Omega$ threshold and $24\mathrm{MeV}$ lower than the $\Lambda \Xi \pi$ threshold. It might appear as a narrow dibaryon resonance and be detectable in the RHIC detector through the reconstruction of the vertex mass of the $\Lambda \Xi$ two-body decay. The effects of explicit $K$ and $\eta$ meson exchange have been studied and found to be negligible in this model. The mechanisms of effective intermediate range attraction, $\sigma$ meson exchange, and kinetic energy reduction due to quark delocalization are discussed.