The results of two experiments designed to synthesize element 115 isotopes in the ${}^{243}\mathrm{Am}+{}^{48}\mathrm{Ca}$ reaction are presented. Two new elements with atomic numbers 113 and 115 were observed for the first time. With 248-MeV ${}^{48}\mathrm{Ca}$ projectiles, we observed three similar decay chains consisting of five consecutive α decays, all detected in a total time interval of 30 s. Each chain was terminated by a spontaneous fission (SF) with a high-energy release and a lifetime of about a day. With 253-MeV ${}^{48}\mathrm{Ca}$ projectiles, we registered a different decay chain of consecutive α decays detected in a time interval of 0.5 s, also terminated by spontaneous fission, but after 1.8 h. The decay properties of the eleven new α- and SF-decaying nuclei are consistent with expectations for consecutive α decays originating from the parent isotopes ${}^{288}$115 and ${}^{287}$115, produced in the 3n- and 4n-evaporation channels, respectively. Support for the assignment of the atomic numbers of all of the nuclei in the ${}^{288}$115 decay chain was obtained in an independent experiment in which a long-lived spontaneous fission activity, ${}^{268}\mathrm{Db}$ (15 events), was found to be chemically consistent with the fifth group of the periodic table. The odd-odd isotope ${}^{288}$115 was observed with largest cross section of about 4 pb. In the SF decay of ${}^{268}\mathrm{Db}$, a total kinetic energy of 230 MeV and a neutron multiplicity per fission of 4.2 were measured. The decay properties of the 11 new isotopes with $Z=105–115$ and the production cross sections are in agreement with modern concepts of the role of nuclear shells in the stability of superheavy nuclei. The experiments were carried out at the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research.

Using the color-singlet free energy $F_1$ and total internal energy $U_1$ obtained by Kaczmarek et al. (hep-lat/0309121) for a static quark Q and an antiquark $\overline{Q}$ in quenched QCD, we study the binding energies and wave functions of heavy quarkonia in a quark-gluon plasma. By minimizing the grand potential in a simplified schematic model, we find that the proper color-singlet $Q\text{−}\overline{Q}$ potential can be obtained from the total internal energy $U_1$ by subtracting the gluon internal energy contributions. We carry out this subtraction in the local energy-density approximation in which the gluon energy density can be related to the local gluon pressure by the quark-gluon plasma equation of state. We find in this approximation that the proper color-singlet $Q\text{−}\overline{Q}$ potential is approximately $F_1$ for $T~T_c$ and it changes to $\frac{3}{4}{F}_1+\frac{1}{4}{U}_1$ at high temperatures. In this potential model, the $J/\psi$ is weakly bound above the phase-transition temperature $T_c$, and it dissociates spontaneously above $1.62T_c$, whereas ${\chi }_c$ and ${\psi }^{\text{'}}$ are unbound in the quark-gluon plasma. The bottomium states $\Upsilon ,{\chi }_b$, and ${\Upsilon }^{\text{'}}$ are bound in the quark-gluon plasma and they dissociate at $4.1T_c,1.18T_c,$ and $1.38T_c$ respectively. For comparison, we evaluate the heavy quarkonium binding energies also in other models using the free energy $F_1$ or the total internal energy $U_1$ as the $Q\text{−}\overline{Q}$ potential. The comparison shows that the model with the new $Q\text{−}\overline{Q}$ potential proposed here gives dissociation temperatures that agree best with those from spectral function analyses. We evaluate the cross section for $\sigma (g+J/\psi \to c+\overline{c})$ and its inverse process to determine the $J/\psi$ dissociation width and the rate of $J/\psi$ production by recombining c and $\overline{c}$ in the quark-gluon plasma.

A fit of the experimental data to the total cross section of the process $\gamma \gamma \to {\pi }^0{\pi }^0$ in the energy region from 270 to 2250 MeV has been carried out using dispersion relations for the invariant amplitudes where the quadrupole polarizabilities are free parameters. As a result the sum and difference of the electric and magnetic quadrupole polarizabilities of the ${\pi }^0$ meson have been found for the first time: $({\alpha }_2+{\beta }_2){}_{{\pi }^0}=(-0.181\pm 0.004)\times {10}^{-4}{\text{fm}}^5$, $({\alpha }_2-{\beta }_2){}_{{\pi }^0}=(39.70\pm 0.02)\times {10}^{-4}{\text{fm}}^5$. In addition, dispersion sum rules have been constructed for this sum and difference, respectively. The values of $({\alpha }_2-{\beta }_2){}_{{\pi }^0}$ and $({\alpha }_2+{\beta }_2){}_{{\pi }^0}$ extracted from the experimental data on the process $\gamma \gamma \to {\pi }^0{\pi }^0$ are in good agreement with the result of calculations in the framework of these dispersion sum rules.

Superdeformation and hyperdeformation in ${}^{108}\mathrm{Cd}$ have been studied for the first time within the framework of the fully self-consistent cranked mean-field theory, namely, cranked relativistic mean-field theory. The structure of observed superdeformed bands 1 and 2 have been analyzed in detail. The bumps seen in their dynamic moments of inertia are explained as arising from unpaired band crossings. This is contrary to an explanation given earlier within the framework of the projected shell model. It was also concluded that this nucleus is not a doubly magic superdeformed nucleus.

The thermal behavior of isoscalar (τ = 0) and isovector (τ = 1) proton-neutron (pn) pairing energies at finite temperature is investigated with shell-model calculations. These pn pairing energies can be estimated by double differences of “thermal” energies that are extended from the double differences of binding energies as indicators of pn pairing energies at zero temperature. We found that the delicate balance between isoscalar and isovector pn pairing energies at zero temperature disappears at a finite temperature. When the temperature rises, while the isovector pn pairing energy decreases, the isoscalar pn pairing energy rather increases. We also discuss the symmetry energy at finite temperature.

We evaluate within a microscopic calculation the contributions of both coherent and incoherent deeply virtual Compton scattering from a spin-0 nucleus. The coherent contribution is obtained when the target nucleus recoils as a whole, whereas for incoherent scattering breakup configurations for the final nucleus into an outgoing nucleon and an $A-1$ system are considered. The two processes encode different characteristics of generalized parton distributions.

The γ decay in the quasicontinuum is used to study the order-to-chaos transition in the thermally excited ${}^{163}\mathrm{Er}$ nucleus. The experimental analysis is performed on high-statistics EUROBALL data, focusing on the spin region $I\approx (20–40)\hslash$, and internal excitation energy up of $\approx 2.5\mathrm{MeV}$. The results are compared to cranked shell model calculations for this nucleus, taking into account the dependence on the K quantum number. Two main topics are investigated. First, the validity of the selection rules associated with the K quantum number are studied as a function of the internal energy U above yrast. K-selection rules are found to be obeyed in the decay along discrete unresolved rotational bands up to $U\approx 1.2\mathrm{MeV}$, whereas in the interval $U\approx 1.2–2.5\mathrm{MeV}$, where the order-to-chaos transition is expected to take place, selection rules are found to be only partially valid. Second, the line-shape analysis of $\gamma -\gamma$ coincidence spectra provides a direct experimental measurement of the rotational and compound damping widths (${\Gamma }_{\mathrm{rot}}$ and ${\Gamma }_{\mu }$), yielding values of 200 and 20 keV, respectively, in good agreement with theory.

A new investigation of the decay scheme of ${}^{99}\mathrm{Y}$ to ${}^{99}\mathrm{Zr}$ removes minor discrepancies between decay and prompt-fission data. The existence of a strongly coupled band on the 725-keV level postulated in an earlier β-decay work is not confirmed. Calculations in the interacting boson fermion framework allow an alternative interpretation of the even-parity levels above 500 keV. Still, the nature of most of these levels above remains unclear.

Measurements of elastic scattering of 21.5 MeV ${\pi }^{\pm }$ by Si, Ca, Ni, and Zr were made by using a single-arm magnetic spectrometer. Absolute calibration was made by parallel measurements of Coulomb scattering of muons. Parameters of a pion-nucleus optical potential were obtained from fits to all eight angular distributions put together. The anomalous s-wave repulsion known from pionic atoms is clearly observed and could be removed by introducing a chiral-motivated density dependence of the isovector scattering amplitude, which also greatly improved the fits to the data. The empirical energy dependence of the isoscalar amplitude also improves the fits to the data but, contrary to what is found with pionic atoms, on its own is incapable of removing the anomaly.

We propose that the parameter-free São Paulo potential be applied in studies of fusion involving weakly bound nuclei in situations in which experimental barrier distributions cannot be obtained. If one aims to study the effect of the breakup process on the fusion cross section, comparison of data with theoretical calculations requires a realistic and trustworthy bare potential. We show that the São Paulo potential has these characteristics.

We present a simple gluon production picture that is based on the McLerran-Venugopalan model and gluon BFKL evolution in relativistic heavy-ion collision. Results for the multiplicity and transverse energy distribution in both the central and forward rapidity regions for gluon production in early stages of heavy-ion collisions at the LHC are given. Finally, we provide a general qualitative discussion of the consequences of the forward rapidity behavior of produced gluons.

We give general expressions for the vector asymmetry in the angular distribution of protons in the nonmesonic weak decay of polarized hypernuclei. From these we derive an explicit expression for the calculation of the asymmetry parameter, $a_{\Lambda }$, which is applicable to the specific cases of ${}_{\Lambda }^5\mathrm{He}$ and ${}_{\Lambda }^{12}C$ described within the extreme shell model. In contrast to the approximate formula widely used in the literature, it includes the effects of three-body kinematics in the final states of the decay and correctly treats the contribution of transitions originating from single-proton states beyond the s-shell. This expression is then used for the corresponding numerical computation of $a_{\Lambda }$ within several one-meson-exchange models. Besides the strictly local approximation usually adopted for the transition potential, we also consider the addition of the first-order nonlocality terms. We find values for $a_{\Lambda }$ ranging from $-0.62$ to $-0.24$, in qualitative agreement with other theoretical estimates but in contradiction with some recent experimental determinations.

Data for scattering of ${}^6\mathrm{He}$ from ${}^{197}\mathrm{Au}$, ${}^{208}\mathrm{Pb}$, and ${}^{209}\mathrm{Bi}$ targets at low energies were consistently analyzed by use of the continuum-discretized coupled-channels method and the dineutron model of the projectile. A very good description of the experimental data was obtained with the strength of the dipole couplings reduced by 50%. We find that the dipole couplings are responsible for the suppression of the Coulomb rainbow and that the quadrupole couplings must be included in the calculations in order to obtain good agreement with the elastic-scattering data at more backward angles.

Particle evaporation rates from excited nuclear systems at equilibrium matter density are studied within the harmonic-interaction Fermi gas model (HIFGM) combined with Weisskopf's detailed balance approach. It is found that thermal expansion of a hot nucleus, as described quantitatively by HIFGM, leads to a significant retardation of particle emission, greatly extending the validity of Weisskopf's approach. The decay of such highly excited nuclei is strongly influenced by surface instabilities.

Angular distributions of ${}^7\mathrm{Li}+{}^{11}\mathrm{B}$ elastic and inelastic scattering were measured at $E_{\mathrm{lab}}$(${}^{11}\mathrm{B}$) $=44\mathrm{MeV}$ for the transitions to the ground and excited states of ${}^7\mathrm{Li}$ and ${}^{11}\mathrm{B}$. The present data and data taken from the literature at $E_{\mathrm{lab}}$(${}^7\mathrm{Li}$) $=34\mathrm{MeV}$ were analyzed within the optical model and coupled-reaction-channels methods. Elastic and inelastic scattering, reorientations of ${}^7\mathrm{Li}$ and ${}^{11}\mathrm{B}$, and the most important one- and two-step transfers were included in the channels-coupling scheme. The dependence of the ${}^7\mathrm{Li}+{}^{11}\mathrm{B}$ optical potential on kinetic energy was taken into account. The deformation parameters of ${}^7\mathrm{Li}$ and ${}^{11}\mathrm{B}$ and optical model parameters for interaction of these nuclei in ground and excited states were deduced. The contributions of one- and two-step transfers to the elastic and inelastic scattering were estimated.

In this work, the charge transfer fluctuation that was previously used for pp collisions is proposed for relativistic heavy-ion collisions as a quark-gluon plasma (QGP) probe. We propose the appearance of a local minimum at midrapidity for the charge transfer fluctuation as a signal for a QGP. Within a two-component neutral cluster model, we demonstrate that the charge transfer fluctuation can detect the presence of a QGP as well as the size of the QGP in the rapidity space. We also show that the forward-backward correlation of multiplicity can be a similarly good measure of the presence of a QGP. Further, we show that the previously proposed net charge fluctuation is sensitive to the existence of the second phase only if the QGP phase occupies a large portion of the available rapidity space.

The mass of the nucleon is studied in a chiral quark-diquark model. Both scalar and axial-vector diquarks are taken into account for the construction of the nucleon state. After the hadronization procedure is used to obtain an effective meson-baryon Lagrangian, the quark-diquark self-energy is calculated to generate the baryon kinetic term as well as determine the mass of the nucleon. It turns out that both the scalar and axial-vector parts of the self-energy are attractive for the mass of the nucleon. We investigate the range of parameters that can reproduce the mass of the nucleon.

The external-field QCD sum rules method is used to evaluate the coupling constant of the light isoscalar-scalar meson (“σ” or ɛ) to the nucleon. The contributions that come from the excited nucleon states and the response of the continuum threshold to the external field are calculated. The obtained value of the coupling constant is compatible with the large value required in one-boson exchange potential models of the two-nucleon interaction.

We study the possible relationship between the saturation properties of nuclear matter and the inclusion of nonlocality in the nucleon-nucleon interaction. To this purpose we compute the saturation curve of nuclear matter within the Bethe-Brueckner-Goldstone theory using a recently proposed realistic nonlocal potential, and compare it with the corresponding curves obtained with a purely local realistic interaction (Argonne $v_{18}$) and the most recent version of the one-boson exchange potential (CD Bonn). We find that the inclusion of nonlocality in the two-nucleon bare interaction strongly affects saturation, but it is unable to provide a consistent description of few-body nuclear systems and nuclear matter.

A recently proposed method, based on dispersion theory, that allows the scattering length of a hadronic two-body system to be extracted from corresponding final-state interactions is generalized to the situation where the Coulomb interaction is present. The steps required in a concrete practical application are discussed in detail. In addition a thorough examination of the accuracy of the proposed method is presented and a comparison is made with results achieved with other methods such as the Jost-function approach based on the effective-range approximation. Deficiencies of the latter method are pointed out. The reliability of the dispersion theory method for also extracting the effective range is investigated.