The α-proton Coulomb interaction is included in the description of α-deuteron scattering using the screening and renormalization approach in the framework of momentum-space three-particle equations. The technical reliability of the method is demonstrated. Large Coulomb-force effects are found.

The new neutron-deficient isotopes ${}^{193,194}\mathrm{Rn}$ have been identified in the complete fusion reaction ${}^{52}\mathrm{Cr}+{}^{144}\mathrm{Sm}$$\to$${}^{196}\mathrm{Rn}$${}^{*}$ at the velocity filter SHIP. The α-decay energy and half-life value of ${}^{194}\mathrm{Rn}$ were determined to be $E_{\alpha }=7700(10)$ keV and $T_{1/2}=0.78(16)$ ms, respectively. For ${}^{193}\mathrm{Rn}$ the half-life of $T_{1/2}=1.15(27)$ ms and two α lines at $E_{\alpha 1}=7685(15)$ keV, $I_{\alpha 1}=74(20)\%$ and $E_{\alpha 2}=7875(20)$ keV, $I_{\alpha 2}=26(12)\%$ were found. The decay pattern of ${}^{193}\mathrm{Rn}$, which is substantially different from that of the heavier odd-$A$ Rn isotopes, provides first experimental evidence for the long-predicted deformation in the very neutron-deficient Rn nuclei.

The nuclear structure of the odd ${}^{105}\mathrm{Mo}$ and ${}^{107}\mathrm{Mo}$ isotopes was reinvestigated in the present work. The excited levels of ${}^{105}\mathrm{Mo}$ were studied by observing prompt γ rays emitted after the spontaneous fission of ${}^{248}\mathrm{Cm}$ with the EUROGAM2 multidetector array. The already well-studied level structure of ${}^{107}\mathrm{Mo}$ was also completed by a search for microsecond isomers. For this purpose, this nucleus was produced by the thermal-neutron-induced fission reaction at the ILL reactor, in Grenoble. We have shown that the experimental level energies and the γ-decay patterns are well reproduced by simple particle-rotor calculations, assuming that these nuclei have an asymmetric shape. The shapes of the odd and even Mo are compared in the neutron range $N=62\text{−}66$.

The β-decay process of the ${}^{11}\mathrm{Li}$ halo nucleus into ${}^9\mathrm{Li}$ and $d$ is studied in a three-body model. The ${}^{11}\mathrm{Li}$ nucleus is described as a ${}^9\mathrm{Li}$$+n+n$ system in hyperspherical coordinates on a Lagrange mesh. Various ${}^9\mathrm{Li}$$+d$ potentials involving a forbidden state, a physical bound state, and a resonance near 0.25 MeV in the $s$ wave are compared. With an added surface absorption, they are compatible with elastic scattering data. The transition probability per time unit is quite sensitive to the location of the resonance. For a fixed resonance location, it does not depend much on the potential choice at variance with the ${}^6\mathrm{He}$ delayed deuteron decay. The calculated transition probability per time unit is larger than the experimental value but the difference can be explained by a slightly higher resonance location and/or by absorption from the ${}^9\mathrm{Li}$$+d$ final channel.

An eikonal expansion is developed to provide systematic corrections to the eikonal approximation through order $1/k^2$, where $k$ is the wave number. The expansion is applied to wave functions for the Klein-Gordon equation and for the Dirac equation with a Coulomb potential. Convergence is rapid at energies above about 250 MeV. Analytical results for the eikonal wave functions are obtained for a simple analytical form of the Coulomb potential of a nucleus. These results are used to investigate distorted-wave matrix elements for quasielastic electron scattering from a nucleus. Focusing factors are shown to arise from the corrections to the eikonal approximation. A precise form of the effective-momentum approximation is developed by use of a momentum shift that depends on the electron's energy loss.

We show that the proton and pion transverse momentum distributions measured at BNL Relativistic Heavy Ion Collider (RHIC), for all collision centralities for pions and most of the collision centralities for protons, can be simultaneously described in terms of a thermal model with common values for the radial flow and temperature, when accounting for the finite size of the interaction region at the time of decoupling. We show that this description is obtained in terms of a simple scaling law of the size of the interaction region with the number of participants in the collision. The behavior of the proton to pion ratio at mid-rapidity can also be understood as a consequence of the strength of the radial flow and system size reached at RHIC energies.

Effects of medium polarization are studied for ${}^1{S}_0$ pairing in neutron and nuclear matter. The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instability of nuclear matter. The self-energy corrections are consistently included resulting in a strong depletion of the Fermi surface. All medium effects are calculated based on the Brueckner theory. The ${}^1{S}_0$ gap is determined from the generalized gap equation. The self-energy corrections always lead to a quenching of the gap, which is enhanced by the screening effect of the pairing potential in neutron matter, whereas it is almost completely compensated by the antiscreening effect in nuclear matter.

A theory of the competition between fusion and quasifission in a heavy fusing system is proposed, which is based on a master equation and the two-center shell model. Fusion and quasifission arise from a diffusion process in an ensemble of nuclear shapes, each of which evolves toward the thermal equilibrium. The fusing system moves on a dynamical (time-dependent) collective potential energy surface that is initially diabatic and gradually becomes adiabatic. Calculations for several reactions leading to ${}^{256}\mathrm{No}$ are performed within a simplified two-dimensional model. Among other important conclusions, the results indicate that (i) the diabatic effects play a very important role in the onset of fusion hindrance for heavy systems and (ii) very asymmetric reactions induced by closed-shell nuclei seem to be the best suited to synthesize the heaviest compound nuclei.

We have developed a fast Monte Carlo procedure of hadron generation that allows one to study and analyze various observables for stable hadrons and hadron resonances produced in ultrarelativistic heavy ion collisions. Particle multiplicities are determined based on the concept of chemical freeze-out. Particles can be generated on the chemical or thermal freeze-out hypersurface represented by a parametrization or a numerical solution of relativistic hydrodynamics with given initial conditions and equation of state. Besides standard spacelike sectors associated with the volume decay, the hypersurface may also include nonspacelike sectors related to the emission from the surface of expanding system. For comparison with other models and experimental data, we demonstrate the results based on the standard parametrizations of the hadron freeze-out hypersurface and flow velocity profile under the assumption of a common chemical and thermal freeze-out. The C++ generator code is written under the ROOT framework and is available for public use at http://uhkm.jinr.ru/.

Based on a multiphase transport model, we have studied the elliptic flow $v_2$ of ϕ mesons from the reconstructed $K^{+}{K}^{-}$ decay channel at the top Relativistic Heavy Ion Collider energy at Brookhaven National Laboratory. The dependences of $v_2$ on transverse momentum $p_T$ and collision centrality are presented and the rescattering effect of ϕ mesons in the hadronic phase is also investigated. The results show that experimental measurement of $v_2$ for ϕ mesons can retain the early collision information before the ϕ decays and that the ϕ $v_2$ value obeys the constituent quark number scaling that has been observed for other mesons and baryons. Our study indicates that the ϕ $v_2$ mostly reflects partonic-level collectivity developed during the early stage of the nucleus-nucleus collision and the strange and light up/down quarks have developed similar angular anistropy properties at the hadronization.

The phenomena of giant halo and halo of neutron-rich even-Ca isotopes are investigated and compared in the frameworks of the relativistic continuum Hartree-Bogoliubov (RCHB) and non-relativistic Skyrme Hartree-Fock-Bogoliubov (HFB) calculations. With two parameter sets for each of the RCHB and the Skyrme HFB calculations, it is found that although halo phenomena exist for Ca isotopes near neutron drip line in both calculations, the halo of the Skyrme HFB calculations starts at a more neutron-rich nucleus than that of the RCHB calculations, and the RCHB calculations have larger neutron root-mean-square (rms) radii systematically in $N⩾40$ than those of the Skyrme HFB calculations. The former difference comes from the difference in shell structure. The reasons for the latter can be partly explained by the neutron $3s_{1/2}$ orbit, causes more than 50% of the difference among the four calculations for neutron rms radii at ${}^{66}\mathrm{Ca}$.

The multimodal random neck rupture model has been employed to study the energy distribution in nuclear fission. Monte Carlo calculations have been carried out on the de-excitation of fission fragments of ${}^{252}\mathrm{Cf}$(sf) using this model. In this study special attention has been paid to the law of conservation of energy. Results for the neutron multiplicities and kinetic energies, average gamma energies are in good agreement with the experimental data. Mass and charge distributions of secondary fission fragments are also well reproduced in the calculations.

The results and conclusions by Ponomarev and Vdovin [Phys. Rev. C 72, 034309 (2005)] are inadequate to judge the applicability of the modified BCS because they were obtained either in the temperature region, where the use of zero-temperature single-particle spectra is no longer justified, or in too limited configuration spaces.

A detailed analysis of the convergence properties of the Andreozzi-Lee-Suzuki iteration method, which is used for the calculation of low-momentum effective potentials $V_{\text{low}k}$, is presented. After summarizing different modifications of the iteration method for one-flavor channels we introduce a simple model to study the generalization of the iteration method to multi-flavor channels. The failure of a straightforward generalization is discussed. The introduction of a channel-dependent cutoff cures the conceptual and technical problems. This novel method has already been applied successfully for realistic hyperon-nucleon interactions.

Rotational structures in the ${}^{169}\mathrm{Ta}$ nucleus were studied via the ${}^{124}\mathrm{Sn}$(${}^{51}\mathrm{V}$, $6n$) reaction. These data were obtained as a side channel of an experiment focusing on ${}^{171}\mathrm{Ta}$, but the sensitivity provided by the Gammasphere spectrometer proved sufficient for a significant extension of the level scheme of this rare-earth nucleus. Over 170 new transitions and four new band structures were placed in ${}^{169}\mathrm{Ta}$, including the intruder $\pi i_{13/2}$ structure. Linking transitions between all of the sequences were identified, and the relative excitation energies between the different configurations were determined for the first time. The rotational sequences were interpreted within the framework of the cranked shell model.

We propose a new theoretical approach to ground and low-energy excited states of nuclei extending the nuclear mean-field theory. It consists of three steps: stochastic preparation of many Slater determinants, the parity and angular-momentum projection, and diagonalization of the generalized eigenvalue problems. The Slater determinants are constructed in the three-dimensional Cartesian coordinate representation capable of describing arbitrary shape of nuclei. We examine feasibility and usefulness of the method by applying the method with the Bonche-Koonin-Negele interaction to light $4N$ nuclei, ${}^{12}\mathrm{C}$, ${}^{16}\mathrm{O}$, and ${}^{20}\mathrm{Ne}$. We discuss difficulties of keeping linear independence for basis states projected on good parity and angular momentum and present a possible prescription.

The argon spectral function is constructed and applied to neutrino-argon cross section computations in the plane wave impulse approximation with the Pauli blocking final state interaction effect taken into account. The approximations of the construction method are critically analyzed using the example of oxygen for which more detailed computations are available. An effective description of the nucleus based on the information contained in a spectral function is proposed. It is demonstrated that its predictions are close to those obtained from the complete spectral function. The effective description can be easily applied in Monte Carlo event generators.

Realistic nucleon-nucleon interactions induce correlations to the nuclear many-body system, which lead to a fragmentation of the single-particle strength over a wide range of energies and momenta. We address the question of how this fragmentation affects the thermodynamical properties of nuclear matter. In particular, we show that the entropy can be computed with the help of a spectral function, which can be evaluated in terms of the self-energy obtained in the self-consistent Green's function approach. Results for the density and temperature dependences of the entropy per particle for symmetric nuclear matter are presented and compared to the results of lowest order finite-temperature Brueckner-Hartree-Fock calculations. The effects of correlations on the calculated entropy are small, if the appropriate quasiparticle approximation is used. The results demonstrate the thermodynamical consistency of the self-consistent $T$-matrix approximation for the evaluation of the Green's functions.