We investigate how coupling of valence $q\overline{q}$ to meson pairs can modify the properties of conventional $q\overline{q}$ and hybrid mesons. In a symmetry limit the mixing between hybrids and conventional $q\overline{q}$ with the same $J^{\mathit{PC}}$ is shown to vanish. Flavor mixing between heavy and light $q\overline{q}$ due to meson loops is shown to be dual to the results of gluon mediated pQCD and qualitatively different from mixing involving light flavors alone. The validity of the OZI rule for conventional $q\overline{q}$ and hybrid mesons is discussed.

Excited states in ${}^{95}\mathrm{Y}$, populated following the spontaneous fission of ${}^{248}\mathrm{Cm}$ and ${}^{252}\mathrm{Cf}$ and following fission of ${}^{235}\mathrm{U}$ induced by thermal neutrons, were studied by means of $\gamma$ spectroscopy using the EUROGAM2 and GAMMASPHERE multidetector Ge arrays and the LOHENGRIN fission-fragment separator, respectively. We have found a new ($17/2^{-}$) isomer in ${}^{95}\mathrm{Y}$ at 3142.2 keV with a half-life of $T_{1/2}=14.9(5)$ ns. Another isomer was identified in ${}^{95}\mathrm{Y}$ at 5022.1 keV and it was assigned a spin-parity ($27/2^{-}$). For this isomer a half-life of $T_{1/2}=65(4)$ ns was determined and four decay branches were found, including an $E3$ decay. A new $E3$ decay branch was also found for the known, 1087.5-keV isomer in ${}^{95}\mathrm{Y}$, for which we measured a half-life of 51.2(9) μs. The $B(E3)$ and $B(E1)$ transition rates, of 2.0 and $3.8\times {10}^{-7}$ W.u., respectively, observed in ${}^{95}\mathrm{Y}$ are significantly lower than in the neighboring ${}^{96}\mathrm{Zr}$ core, suggesting that octupole correlations in this region are mainly due to the coupling of proton $\Delta j=3$ orbitals. Shell-model calculations indicate that the ($27/2^{-}$) isomer in ${}^{95}\mathrm{Y}$ corresponds to the $\pi g_{9/2}\nu (g_{7/2}{h}_{11/2})$ maximally aligned configuration and that all three isomers in ${}^{95}\mathrm{Y}$ decay, primarily, by $M2$ transitions between proton $g_{9/2}$ and $f_{5/2}$ orbitals.

Fine structure in the region of the isoscalar giant quadrupole resonance (ISGQR) in ${}^{58}\mathrm{Ni}$, ${}^{89}\mathrm{Y}$, ${}^{90}\mathrm{Zr}$, ${}^{120}\mathrm{Sn}$, ${}^{166}\mathrm{Er}$, and ${}^{208}\mathrm{Pb}$ has been observed in high-energy-resolution ($\Delta E_{1/2}\simeq 35\text{−}50$ keV) inelastic proton scattering measurements at $E_0=200$ MeV at iThemba LABS. Calculations of the corresponding quadrupole excitation strength functions performed within models based on the random-phase approximation (RPA) reveal similar fine structure when the mixing of one-particle one-hole states with two-particle two-hole states is taken into account. A detailed comparison of the experimental data is made with results from the quasiparticle-phonon model (QPM) and the extended time-dependent Hartree-Fock (ETDHF) method. For ${}^{208}\mathrm{Pb}$, additional theoretical results from second RPA and the extended theory of finite Fermi systems (ETFFS) are discussed. A continuous wavelet analysis of the experimental and the calculated spectra is used to extract dominant scales characterizing the fine structure. Although the calculations agree with qualitative features of these scales, considerable differences are found between the model and experimental results and amongst different models. Within the framework of the QPM and ETDHF calculations it is possible to decompose the model spaces into subspaces approximately corresponding to different damping mechanisms. It is demonstrated that characteristic scales mainly arise from the collective coupling of the ISGQR to low-energy surface vibrations.

We present results for final state charged-particle (pseudo-)rapidity distributions in $p+\overline{p}/p+p$ and $\mathrm{Pb}+\mathrm{Pb}/\mathrm{Au}+\mathrm{Au}$ at ultra high energies ($17.3\hspace{0.5em}\mathrm{GeV}⩽\sqrt{s_{\mathit{NN}}}⩽14\hspace{0.5em}\mathrm{TeV}$) from the Ultra-relativistic Quantum Molecular Dynamics (UrQMD-v2.3) model. In addition, excitation functions of produced charged-particle multiplicities ($N_{\mathrm{ch}}$) and pseudorapidity spectra are investigated up to CERN Large Hadron Collider energies. Good agreement is observed between UrQMD and measured pseudorapidity distributions of charged particles up to the highest Tevatron and $\mathrm{Sp}\overline{\mathrm{p}}\mathrm{S}$ energies.

We study the ground and the first excited intrinsic states of ${}^{53}\mathrm{Co}$ and its mirror nucleus ${}^{53}\mathrm{Fe}$, within the frameworks of the relativistic and nonrelativistic mean field formalisms. The analysis of the single-particle energy spectra of these nuclei show a competition of spins $1/2^{-}$ and $3/2^{-}$ in a low-lying excited state, which agrees well with the recent experimental observation [D. Rudolph et al., Eur. Phys. J. A 36, 131 (2008)] of spin and parity $J^{\pi }=3/2^{-}$ for the isomeric configuration in ${}^{53}\mathrm{Co}$.

Nucleosynthesis in type I X-ray bursts may involve up to several thousand nuclear processes. The majority of these processes have only been determined theoretically due to the lack of sufficient experimental information. Accurate reaction $Q$-values are essential for reliable theoretical estimates of reaction rates. Those reactions with small $Q$-values ($<1$ MeV) are of particular interest in these environments as they may represent waiting points for a continuous abundance flow toward heavier-mass nuclei. To explore the nature of these waiting points, we have performed a comprehensive series of post-processing calculations which examine the sensitivity of nucleosynthesis in type I X-ray bursts to uncertainties in reaction $Q$-values. We discuss and list the relatively few critical masses for which measurements could better constrain the results of our studies. In particular, we stress the importance of measuring the mass of ${}^{65}\mathrm{As}$ to obtain an experimental $Q$-value for the ${}^{64}\mathrm{Ge}(p,\gamma ){}^{65}\mathrm{As}$ reaction.

We present a formalism for calculating nuclear matrix elements of double-$\beta$ decay within the framework of the microscopic interacting boson model. We calculate Fermi, Gamow-Teller, and tensor matrix elements in the decay of Ge-Se-Mo-Te-Xe-Nd-Sm and compare our results with those of the shell-model (SM) and of the quasiparticle random-phase approximation (QRPA). Our results are in agreement with QRPA. We discuss simple features of the matrix elements and give a formula that allows one to estimate matrix elements in terms of the number of valence proton and neutron pairs.

We discuss the dark-matter detection rates for the elastic and inelastic scattering of the lightest supersymmetric particle (LSP) off nuclei. For this we use an easily accessible formalism where the underlying nuclear physics is condensed in structure coefficients multiplying the key parameters of supersymmetric theories. In this work we compute these coefficients for the stable iodine, xenon, and cesium nuclei by application of the nuclear shell model in a model space involving the $2s$, $1d$, $0g_{7/2}$, and $0h_{11/2}$ single-particle orbitals. As an interaction we use the renormalized Bonn-CD $G$ matrix. By using fitted nuclear gyromagnetic factors we have successfully reproduced the relevant spectroscopic data on magnetic moments and $M1$ decays in the discussed nuclei.

An experiment was conducted to observe triple- and quadruple-escape peaks, at a photon energy equal to 6.128 MeV, in the spectra recorded with a high-purity Ge detector working in coincidence with six bismuth germanate detectors. The peak intensities may be explained having recourse to only the bremsstrahlung cascade process of consecutive electron-positron pair creation; i.e., the contribution of simultaneous double pair formation (and other cascade effects) is much smaller. The experimental peak areas are in reasonably good agreement with those predicted by Monte Carlo simulations done with the general-purpose radiation-transport code PENELOPE.

We study matter at high density and temperature using a chiral Lagrangian in which the breaking of scale invariance is regulated by the value of a scalar field, called dilaton [E. K. Heide, S. Rudaz, and P. J. Ellis, Nucl. Phys. A571, 713 (1994); G. W. Carter, P. J. Ellis, and S. Rudaz, Nucl. Phys. A603, 367 (1996); G. W. Carter, P. J. Ellis, and S. Rudaz, Nucl. Phys. A618, 317 (1997); G. W. Carter and P. J. Ellis, Nucl. Phys. A628, 325 (1998)]. We provide a phase diagram describing the restoration of chiral and scale symmetries. We show that chiral symmetry is restored at large temperatures, but at low temperatures it remains broken at all densities. We also show that scale invariance is more easily restored at low rather than large baryon densities. The masses of vector-mesons scale with the value of the dilaton and their values initially slightly decrease with the density but then they increase again for densities larger than $~3{\rho }_0$. The pion mass increases continuously with the density and at ${\rho }_0$ and $T=0$ its value is $~30$ MeV larger than in the vacuum. We show that the model is compatible with the bounds stemming from astrophysics, as, e.g., the one associated with the maximum mass of a neutron star. The most striking feature of the model is a very significant softening at large densities, which manifests also as a strong reduction of the adiabatic index. Although the softening has probably no consequence for supernova explosion via the direct mechanism, it could modify the signal in gravitational waves associated with the merging of two neutron stars.

We discuss the effects of initial collision geometry and centrality bin definition on correlation and fluctuation observables in nucleus-nucleus collisions. We focus on the forward-backward correlation coefficient recently measured by the STAR Collaboration in $\mathrm{Au}+\mathrm{Au}$ collisions at RHIC. Our study is carried out within two models: the Glauber Monte Carlo code with a “toy” wounded-nucleon model and the hadron-string dynamics (HSD) transport approach. We show that strong correlations can arise from averaging over events in one centrality bin. We, furthermore, argue that a study of the dependence of correlations on the centrality bin definition as well as the bin size may distinguish between these trivial correlations and correlations arising from new physics.

We use the Kharzeev-Levin-Nardi (KLN) model of the low $x$ gluon distributions to fit recent HERA data on $F_L$ and $F_2^c(F_2^b)$. Having checked that this model gives a good description of the data, we use it to predict $F_L$ and $F_2^c$ to be measured in a future electron-ion collider. The results are similar to those obtained with the de Florian-Sassot and Eskola-Paukkunen-Salgado nuclear gluon distributions. The conclusion of this exercise is that the KLN model, simple as it is, may still be used as an auxiliary tool to make estimates for both heavy-ion and electron-ion collisions.

The effect of the crystal lattice on nuclear fusion reactions $p+d\to {}^3\mathrm{He}$ taking place in internal conversion channels is studied. Fusionable particles solved in the investigated crystalline material form a sublattice. Fusion reaction is generated by a flux of incoming fusionable particles. The calculated cross sections are compared with those of an ordinary fusion reaction. The internal conversion coefficients are also calculated.

The mass of ${}^{11}\mathrm{Li}$ has been determined from $Q$-value measurements of the ${}^1\mathrm{H}({}^{11}\mathrm{Li},{}^9\mathrm{Li}){}^3\mathrm{H}$ reaction. The experiment was performed at TRIUMF laboratory with the GANIL active target MAYA. Energy-energy and angle-angle kinematics reconstruction give a $Q$ value of 8.119(22) MeV for the reaction. The derived ${}^{11}\mathrm{Li}$ two-neutron separation energy is $S_{2n}=363(22)$ keV.

The chiral susceptibility is given by the scalar vacuum polarization at zero total momentum. This follows directly from the expression for the vacuum quark condensate so long as a nonperturbative symmetry preserving truncation scheme is employed. For QCD in-vacuum the susceptibility can rigorously be defined via a Pauli-Villars regularization procedure. Owing to the scalar Ward identity, irrespective of the form or Ansatz for the kernel of the gap equation, the consistent scalar vertex at zero total momentum can automatically be obtained and hence the consistent susceptibility. This enables calculation of the chiral susceptibility for markedly different vertex Ansätze. For the two cases considered, the results were consistent and the minor quantitative differences easily understood. The susceptibility can be used to demarcate the domain of coupling strength within a theory upon which chiral symmetry is dynamically broken. Degenerate massless scalar and pseudoscalar bound-states appear at the critical coupling for dynamical chiral symmetry breaking.

We generalize the leading twist theory of nuclear shadowing and calculate quark and gluon generalized parton distributions (GPDs) of spinless nuclei. We predict very large nuclear shadowing for nuclear GPDs. In the limit of the purely transverse momentum transfer, our nuclear GPDs become impact-parameter-dependent nuclear parton distribution functions (PDFs). Nuclear shadowing induces nontrivial correlations between the impact parameter $b$ and the light-cone fraction $x$. We make predictions for the deeply virtual Compton scattering (DVCS) amplitude and the DVCS cross section on ${}^{208}\mathrm{Pb}$ at high energies. We calculate the cross section of the Bethe-Heitler (BH) process and address the issue of the extraction of the DVCS signal from the $eA\to e\gamma A$ cross section. We find that the $eA\to e\gamma A$ differential cross section is dominated by DVCS at the momentum transfer $t$ near the minima of the nuclear form factor. We also find that nuclear shadowing leads to dramatic oscillations of the DVCS beam-spin asymmetry, $A_{\mathit{LU}}$, as a function of $t$. The position of the points where $A_{\mathit{LU}}$ changes sign is directly related to the magnitude of nuclear shadowing.

Excited states in the nucleus ${}^{133}\mathrm{Sb}$, populated in the fission of ${}^{235}\mathrm{U}$ induced by thermal neutrons were studied using the Lohengrin fission-fragment separator. A new 4191.8 keV level in ${}^{133}\mathrm{Sb}$, populated in the decay of the 16.6 μs isomer, was observed. The level is interpreted as the ${11/2}^{+}$ member of the $\pi g_{7/2}\otimes \mathrm{core}$ configuration, predicted by the shell model at 4095 keV. Levels corresponding to octupole excitation of the ${}^{132}\mathrm{Sn}$ core, identified previously in prompt-$\gamma$ measurement, were now observed in the isomeric decay.

The study of rotation-alignment of quasiparticles probes sensitively the properties of high-$j$ intruder orbits. The distribution of very-high-$j$ orbits, which are consequences of the fundamental spin-orbit interaction, links with the important question of single-particle levels in superheavy nuclei. With the deformed single-particle states generated by the standard Nilsson potential, we perform Projected Shell Model calculations for transfermium nuclei where detailed spectroscopy experiments are currently possible. Specifically, we study the systematical behavior of rotation-alignment and associated band-crossing phenomenon in Cf, Fm, and No isotopes. Neutrons and protons from the high-$j$ orbits are found to compete strongly in rotation-alignment, which gives rise to testable effects. Observation of these effects will provide direct information on the single-particle states in the heaviest nuclear mass region.

Properties of multi-antikaonic nuclei (MKN), where several numbers of $K^{-}$ mesons are bound, are studied in the relativistic mean-field model, combined with chiral dynamics for the kaonic part of the thermodynamic potential. The density profiles for nucleons and $K^{-}$ mesons, the single particle energy of the $K^{-}$ mesons, and binding energy of the MKN are obtained. The effects of the $\overline{K}\text{−}\overline{K}$ interactions on these quantities are discussed in comparison with other meson ($\sigma$, $\omega$, and $\rho$)-exchange models. It is shown that the $\overline{K}\text{−}\overline{K}$ interactions originate from two contributions: One is the contact interaction between antikaons inherent in chiral symmetry, and the other is the one generated through coupling between the $K^{-}$ and meson mean fields. Both effects of the $\overline{K}\text{−}\overline{K}$ repulsive interactions become large on the ground state properties of the MKN as the number of the embedded $K^{-}$ mesons increases. A relation between the multi-antikaonic nuclei and kaon condensation in infinite and uniform matter is mentioned.