It is shown that the Bohr Hamiltonian in the intrinsic frame used for the description of the low-lying vibrational states in the well-deformed nuclei can be presented in two different forms. In the first form the Hamiltonian has three different mass coefficients but the quadrupole transition operator has a standard form with one parameter only. The second form of the Hamiltonian can be derived by a transformation from $\beta$ and $\gamma$ to the new variables. In this form the Hamiltonian contains only one mass coefficient but the quadrupole operator takes a different form with three parameters. It is shown also that this Hamiltonian can describe a situation when a collectivity of the vibrational states is rather low, but their excitation energies are relatively small, while the $E2$ transitions inside the bands are very strong.

General formulation of hydrodynamics describing transversally thermalized matter created at the early stages of ultrarelativistic heavy-ion collisions is presented. Similarities and differences with the standard three-dimensionally thermalized relativistic hydrodynamics are discussed. The role of the conservation laws as well as the thermodynamic consistency of two-dimensional thermodynamic variables characterizing transversally thermalized matter is emphasized.

We make a thorough study of the process of three-body kaon absorption in nuclei, in connection with a recent FINUDA experiment which claims the existence of a deeply bound kaonic state from the observation of a peak in the $\Lambda d$ invariant mass distribution following $K^{-}$ absorption on ${}^6\mathrm{Li}$. We show that the peak is naturally explained in terms of $K^{-}$ absorption from three nucleons leaving the rest as spectators. We can also reproduce all the other observables measured in the same experiment and used to support the hypothesis of the deeply bound kaon state. Our study also reveals interesting aspects of kaon absorption in nuclei, a process that must be understood in order to make progress in the search for $K^{-}$ deeply bound states in nuclei.

In the present work we apply a quantum hadrodynamic effective model in the mean-field approximation to the description of neutron stars. We consider an adjustable derivative-coupling model and study the parameter influence on the dynamics of the system by analyzing the full range of values they can take. We establish a set of parameters that define a specific model that can describe phenomenological properties such as the effective nucleon mass at saturation as well as global static properties of neutron stars (mass and radius). If one uses observational data to fix the maximum mass for neutron stars by a specific model, we can predict the compression modulus of nuclear matter, which is found to be $K=257.2$ MeV.

${}^3{P}_2$ superfluidity of neutrons in neutron star matter is investigated using several potential models and the separation method. As a first step, the dependence of the pure ${}^3{P}_2$ energy gap on the projection $M$ of total momentum $J$ is analyzed. The energy gap functions for pure ${}^3{P}_2$ pairing are treated as vectors indexed by $M$, and it is shown that the magnitudes of these vectors at Fermi surface are close to each other, whereas their components are different. On the basis of these works, the influence of hyperons on the energy gap for ${}^3{P}_2$ neutron pairing, with and without coupling to the ${}^3{F}_2$ state, at Fermi surface in neutron star matter is studied. The results show that in the OPEG case hyperons increase the energy gap when the baryon number density is in the range of 0.2 fm${}^{-3}<n_B<0.33$ fm${}^{-3}$ and reduce it when $n_B>0.33$ fm${}^{-3}$, and in the Argonne $\upsilon 18$ case hyperons increase the energy gap in the whole range where the ${}^3{P}_2$ superfluidity exists. The energy gaps are zero in two types of neutron star matter for the Bonn potential.

An approach to pairing in finite nuclei at nonzero temperature is proposed, which incorporates the effects due to the quasiparticle-number fluctuation (QNF) around Bardeen-Cooper-Schrieffer (BCS) mean field and dynamic coupling to quasiparticle-pair vibrations within the self-consistent quasiparticle random-phase approximation (SCQRPA). The numerical calculations of pairing gap, total energy, and heat capacity were carried out within a doubly folded multilevel model as well as realistic nuclei ${}^{56}\mathrm{Fe}$ and ${}^{120}\mathrm{Sn}$. The results obtained show that, under the effect of QNF, in the region of moderate and strong couplings, the sharp transition between the superconducting and normal phases is smoothed out, resulting in a thermal pairing gap, which does not collapse at the BCS critical temperature, but has a tail, which extends to high temperature. The dynamic coupling of quasiparticles to SCQRPA vibrations significantly improves the agreement with the results of exact calculations and those obtained within the finite-temperature quantal Monte Carlo method for the total energy and heat capacity. It also causes a deviation of the quasiparticle occupation numbers from the Fermi-Dirac distributions for free fermions.

The photon bremsstrahlung rate from a quark jet produced in deep-inelastic scattering (DIS) off a large nucleus is studied in the collinear limit. The leading medium-enhanced higher twist corrections that describe the multiple scattering of the jet in the nucleus are re-summed to all orders of twist. The propagation of the jet in the absence of further radiative energy loss is shown to be governed by a transverse momentum diffusion equation. We compute the final photon spectrum in the limit of soft photons, taking into account the leading and next-to-leading terms in the photon momentum fraction $y$. In this limit, the photon spectrum in a physical gauge is shown to arise from two interfering sources: one where the initial hard scattering produces an off-shell quark, which immediately radiates the photon and then undergoes subsequent soft rescattering, and an alternative in which the quark is produced on-shell and propagates through the medium until it is driven off-shell by rescattering and radiates the photon. Our result has a simple formal structure as a product of the photon splitting function, the quark transverse momentum distribution coming from a diffusion equation, and a dimensionless factor that encodes the effect of the interferences encountered by the propagating quark over the length of the medium. The destructive nature of such interferences in the small-$y$ limit is responsible for the origin of the Landau-Pomeranchuck-Migdal (LPM) effect. Along the way we also discuss possible implications for quark jets in hot nuclear matter.

It is shown that the number of independent operators in the nucleon-nucleon parity violating contact Lagrangian at the leading order in the low-momentum expansion can be reduced to five by using Fierz rearrangements of the nucleon fields.

We measured ${}^{14}\mathrm{O}+{}^4\mathrm{He}$ excitation functions for elastic scattering which demonstrate, for the first time, a well developed $\alpha$-cluster structure in the proton rich nucleus, ${}^{18}\mathrm{Ne}$. We present the excitation energies and estimates of the spins for the dominant resonances using an R-matrix approach. A resonance at 9.2 MeV excitation energy in ${}^{18}\mathrm{Ne}$ is particularly interesting. The spin-parity of the state is found to be $3^{-}$ and the $\alpha$ particle reduced width for the state appears to be comparable to the single particle limit. We have found indications for unusually large size of the observed $\alpha$-cluster configuration.

Fragment mass distributions for fission after full momentum transfer were measured for the reaction ${}^{36}\mathrm{S}+{}^{238}\mathrm{U}$ at bombarding energies around the Coulomb barrier. The data revealed a transition from symmetry to asymmetry mass distributions when the beam energies were decreased from above-barrier to sub-barrier values. The main components of the asymmetric mass distribution are at $A_{\mathrm{H}}\approx 200$ and $A_{\mathrm{L}}\approx 74$. The asymmetric fission is attributed to quasifission of the reacting system at polar collisions, whereas the symmetric fission originates from the compound nucleus produced in equatorial collisions. The results suggest a strong influence of orientation effects of the deformed target nuclei on fusion.

We investigated half-life changes with temperature of ${}^{22}\mathrm{Na}$ embedded in Al and ${}^{198}\mathrm{Au}$/${}^{196}\mathrm{Au}$ embedded in Au. We do not find any change of the half-life between room temperature and 10 K on the level of 0.04% for ${}^{22}\mathrm{Na}$, 0.03% for ${}^{198}\mathrm{Au}$, and 0.5% for ${}^{196}\mathrm{Au}$ in striking disagreement with the first experimental works and predictions. Additionally, the absolute half-life for ${}^{198}\mathrm{Au}$ has been determined to $2.6937\pm 0.0003$ d which is 5 standard deviations below the recommended NIST value but in agreement with other high-precision measurements.

The coexistence of the $\alpha +\alpha +n+n$ and $\alpha +t+t$ cluster structures in the excited states of ${}^{10}\mathrm{Be}$ has been discussed. In the previous analysis, all the low-lying states of ${}^{10}\mathrm{Be}$ were found to be well described by the motion of the two valence neutrons around two α clusters. However, the $\alpha +t+t$ cluster structure was found to coexist with the $\alpha +\alpha +n+n$ structure around $E_x=15$ MeV, close to the corresponding threshold. We have introduced a microscopic model to solve the coupling effect between these two configurations. The $K=0$ and $K=1$ states are generated from the $\alpha +t+t$ configurations due to the spin coupling of two triton clusters. The present case of ${}^{10}\mathrm{Be}$ is one of the few examples in which completely different configurations of triton-type ($\alpha +t+t$ three-center) and α-type ($\alpha +\alpha +n+n$ two-center) clusters coexist in a single nucleus in the same energy region.

New sub-$\mu$s isomers have been observed in the neutron-rich Sn isotopes. ${}^{125,127,129}\mathrm{Sn}$ nuclei have been produced in a relativistic fission reaction of ${}^{238}\mathrm{U}$ on a ${}^9\mathrm{Be}$ target at 750 $A·\mathrm{MeV}$ and by the fragmentation of ${}^{136}\mathrm{Xe}$ at 600 $A·\mathrm{MeV}$ populating high-spin yrast states. In addition to the already known $\mu$s isomers, three new ones with sub-$\mu$s half-lives have been observed. These yrast isomers are the high-spin members of the $\nu (d_{3/2}^{-1}{h}_{11/2}^{-2})$ and $\nu h_{11/2}^{-n}$, seniority $v=3$ multiplets leading to isomeric ($23/2^{+}$) and ($27/2^{-}$) states, respectively. Added to the already known $19/2^{+}\mu$s isomers in this region the current work completes the systematic information of neutron-hole excitations toward the filling of the last $h_{11/2}$ orbital at $N=82$. The results are discussed in the framework of state-of-the-art shell-model calculations using realistic interactions.

The possible constraints on the poorly determined symmetry part of the effective nuclear Hamiltonians or effective energy functionals, i.e., the so-called symmetry energy $S(\rho )$, are very much under debate. In the present work, we show that the value of the symmetry energy associated with Skyrme functionals, at densities ρ around 0.1 fm${}^{-3}$, is strongly correlated with the value of the centroid of the Giant Dipole Resonance (GDR) in spherical nuclei. Consequently, the experimental value of the GDR in, e.g., ${}^{208}\mathrm{Pb}$ can be used as a constraint on the symmetry energy, leading to $23.3\hspace{0.17em}\mathrm{MeV}<S(\rho =0.1\hspace{0.17em}{\mathrm{fm}}^{-3})<24.9$ MeV.

At low densities, with decreasing temperatures, in symmetric nuclear matter α particles are formed, which eventually give raise to a quantum condensate with four-nucleon α-like correlations (quartetting). Starting with a model of α matter, where undistorted α particles interact via an effective interaction such as the Ali-Bodmer potential, the suppression of the condensate fraction at zero temperature with increasing density is considered. Using a Jastrow-Feenberg approach, it is found that the condensate fraction vanishes near saturation density. Additionally, the modification of the internal state of the α particle due to medium effects will further reduce the condensate. In finite systems, an enhancement of the $S$-state wave function of the center-of-mass orbital of α-particle motion is considered as the correspondence to the condensate. Wave functions have been constructed for self-conjugate $4n$ nuclei that describe the condensate state but are fully antisymmetrized on the nucleonic level. These condensate-like cluster wave functions have been successfully applied to describe properties of low-density states near the $n\alpha$ threshold. Comparison with orthogonality condition model calculations in ${}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O}$ shows strong enhancement of the occupation of the $S$-state center-of-mass orbital of the α particles. This enhancement is decreasing if the baryon density increases, similar to the density-induced suppression of the condensate fraction in α matter. The ground states of ${}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O}$ show no enhancement at all, thus a quartetting condensate cannot be formed at saturation densities.

Proton-proton correlations were observed for the two-proton decays of the ground states of ${}^{19}\mathrm{Mg}$ and ${}^{16}\mathrm{Ne}$. The trajectories of the respective decay products, ${}^{17}\mathrm{Ne}$+$p+p$ and ${}^{14}\mathrm{O}$+$p+p$, were measured by using a tracking technique with microstrip detectors. These data were used to reconstruct the angular correlations of fragments projected on planes transverse to the precursor momenta. The measured three-particle correlations reflect a genuine three-body decay mechanism and allowed us to obtain spectroscopic information on the precursors with valence protons in the $\mathit{sd}$ shell.

We examine the magnetic moments and $\beta$-decay lifetimes of light $T=\frac{1}{2}$ mirror nuclei and obtain very tight correlations between these quantities by making use of shell-model estimates for small quantities. Using the information thus obtained, we predict values for some unknown magnetic moments of heavier $T=\frac{1}{2}$ mirror nuclei. Correlations for the magnetic moments of some $T=\frac{3}{2}$ mirror nuclei are also included. The effective operators required to reproduce the data are discussed and compared to those obtained with other methods.

The half-life of an isomer in ${}^{164}\mathrm{Ho}$ was measured by using photodisintegration reactions. The photons were generated by Compton scattering of laser photons and relativistic electrons at the electron storage ring NewSUBARU in the super photon ring 8-GeV (SPring-8) facility. The half-life is $36.4\pm 0.3$ min. This value is about 3% shorter than the previous value $37.5_{-0.5}^{+1.5}$ min reported in 1966.

Antiparticle to particle ratios for identified protons, kaons, and pions at $\sqrt{s_{\mathit{NN}}}=62.4$ and 200 GeV in Cu+Cu collisions are presented as a function of centrality for the midrapidity region of $0.2<\eta <1.4$. No strong dependence on centrality is observed. For the $\langle \overline{p}\rangle /\langle p\rangle$ ratio at $\langle p_T\rangle \approx 0.51$ GeV/$c$, we observe an average value of $0.50\pm 0.{003}_{(\mathrm{stat})}\pm 0.{04}_{(\mathrm{syst})}$ and $0.77\pm 0.{008}_{(\mathrm{stat})}\pm 0.{05}_{(\mathrm{syst})}$ for the 10% most central collisions of 62.4 and 200 GeV $\mathrm{Cu}+\mathrm{Cu}$, respectively. The values for all three particle species measured at $\sqrt{s_{\mathit{NN}}}=200$ GeV are in agreement within systematic uncertainties with that seen in both heavier and lighter systems measured at the same RHIC energy. This indicates that system size does not appear to play a strong role in determining the midrapidity chemical freeze-out properties affecting the antiparticle to particle ratios of the three most abundant particle species produced in these collisions.

We present the first spin alignment measurements for the $K^{*0}(892)$ and $\varphi (1020)$ vector mesons produced at midrapidity with transverse momenta up to 5 GeV/$c$ at $\sqrt{s_{\mathit{NN}}}=200$ GeV at RHIC. The diagonal spin-density matrix elements with respect to the reaction plane in $\mathrm{Au}+\mathrm{Au}$ collisions are ${\rho }_{00}=0.32\pm 0.04$ (stat) ± 0.09 (syst) for the $K^{*0}$ ($0.8<p_T<5.0$ GeV/$c$) and ${\rho }_{00}=0.34\pm 0.02$ (stat) ± 0.03 (syst) for the $\varphi$ ($0.4<p_T<5.0$ GeV/$c$) and are constant with transverse momentum and collision centrality. The data are consistent with the unpolarized expectation of 1/3 and thus no evidence is found for the transfer of the orbital angular momentum of the colliding system to the vector-meson spins. Spin alignments for $K^{*0}$ and $\varphi$ in $\mathrm{Au}+\mathrm{Au}$ collisions were also measured with respect to the particle's production plane. The $\varphi$ result, ${\rho }_{00}=0.41\pm 0.02$ (stat) ± 0.04 (syst), is consistent with that in $p+p$ collisions, ${\rho }_{00}=0.39\pm 0.03$ (stat) ± 0.06 (syst), also measured in this work. The measurements thus constrain the possible size of polarization phenomena in the production dynamics of vector mesons.