The properties of inhomogeneous nuclear matter are investigated considering the self-consistent Skyrme-Hartree-Fock approach with inclusion of pairing correlations. For a comparison we also consider a relativistic mean-field approach. The inhomogeneous infinite matter is described in terms of cubic Wigner-Seitz cells, which leads to a smooth transition to the limit of homogeneous nuclear matter. The possible existence of various structures in the so-called pasta phase is investigated within this self-consistent approach and a comparison is made to results obtained within the Thomas-Fermi approximation. Results for the proton abundances and the pairing properties are discussed for densities for which clustering phenomena are obtained.

The mass spectra of heavy and light mesons is computed within the framework of the relativistic flux tube model. A good agreement with the experimental data is obtained provided that the flux tube contributions, including retardation and spin-orbit effects, are supplemented by a one-gluon-exchange potential, a quark self-energy term, and instanton-induced interactions. No arbitrary constant is needed to fit the absolute scale of the mass spectra, and the different parameters are fitted on lattice QCD to strongly restrict the arbitrariness of our model. The relevance of the present approach is discussed in the case of glueballs, and the glueball spectrum we compute is compared to the lattice QCD one. Finally, we make connections between the results of our model and the nature of some newly discovered experimental states such as the $f_0(1810),X(3940)$, and $Y(3940)$.

In this article, we study the structure of the ρ meson in the framework of the coupled rainbow Schwinger-Dyson equation and ladder Bethe-Salpeter equation with a confining effective potential. The $u$ and $d$ quark propagators get significantly modified, the mass poles are absent in the timelike region, which implements confinement naturally. The Bethe-Salpeter amplitudes of the ρ meson center around zero momentum and extend to the energy scale about $q^2=1{\mathrm{GeV}}^2$, which happens to be the energy scale of chiral symmetry breaking, strong interactions in the infrared region result in bound state. The numerical results of the mass and decay constant of the ρ meson are in agreement with the experimental data.

We measured large-angle quasielastic scattering for the spherical ${}^{16,17,18}\mathrm{O}+{}^{92}\mathrm{Mo}$ systems at deep sub-barrier energies. This is a process sensitive to the surface region of the nuclear potential which can be used to probe surface diffuseness. The derived diffuseness values are of the order of 0.70 fm for the three systems, larger than predicted by previous works on similar systems.

We invert experimental data for heavy-ion fusion reactions at energies well below the Coulomb barrier in order to directly determine the internucleus potential between the colliding nuclei. In contrast to the previous applications of the inversion formula, we explicitly take into account the effect of channel couplings on fusion reactions, by assuming that fusion cross sections at deep sub-barrier energies are governed by the lowest barrier in the barrier distribution. We apply this procedure to the ${}^{16}\mathrm{O}+{}^{144}\mathrm{Sm}$ and ${}^{16}\mathrm{O}+{}^{208}\mathrm{Pb}$ reactions, and find that the inverted internucleus potential are much thicker than phenomenological potentials. A relation to the steep fall-off phenomenon of fusion cross sections recently found at deep sub-barrier energies is also discussed.

The momentum distribution of relative motion between two nucleons gives information on the correlation in nuclei. The momentum distribution is calculated for both ${}^6\mathrm{He}$ and ${}^6\mathrm{Li}$, which are described in a three-body model of $\alpha +N+N$. The ground-state solution for the three-body Hamiltonian is obtained accurately using correlated basis functions. The momentum distribution depends on the potential model for the $N\text{−}N$ interaction. With use of a realistic potential, the ${}^6\mathrm{He}$ momentum distribution exhibits a dip around 2 fm${}^{-1}$ characteristic of $S$-wave motion. In contrast to this, the ${}^6\mathrm{Li}$ momentum distribution is very similar to that of the deuteron; no dip appears because it is filled with the $D$-wave component arising from the tensor force.

The dual observation of the Ω production in central Au-Au collisions having both an exponential $p_T$ distribution and also associated particles above the background has been referred to as the Ω puzzle. We give a quantitative description of how that puzzle can be understood in terms of phantom jets, where only ridges without peaks are produced to give rise to both the Ω trigger and its associated particles. In the framework of recombination of thermal partons we are able to reproduce both the $\Delta \varphi$ distribution and the trigger-momentum dependence of the yield of the associated particles. We make predictions on other observables that can be checked by further analyses of the data.

We report on a study of π and η decays of strange baryon resonances within relativistic constituent-quark models based on one-gluon-exchange and Goldstone-boson-exchange dynamics. The investigations are performed in the point form of Poincaré-invariant relativistic quantum mechanics with a spectator-model decay operator. The covariant predictions of the constituent-quark models underestimate the experimental data in most cases. These findings are congruent with an earlier study of nonstrange baryon decays in the light-flavor sector. We also consider a nonrelativistic reduction of the point-form spectator model, which leads to the decay operator of the elementary emission model. For some decays the nonrelativistic results differ substantially from the relativistic ones and they exhibit no uniform behavior as they scatter above and below the experimental decay widths.

A simple model based on relativistic geometry and final-state hadronic rescattering is used to predict pion source parameters extracted in two-pion correlation studies of proton-proton collisions at $\sqrt{s}=14$ TeV. By comparing the results of these model studies with data, it might be possible to obtain information on the hadronization time in these collisions. As a test of this model, comparisons between existing two-pion correlation data at $\sqrt{s}=1.8$ TeV and results from the model are made. It is found at this lower energy that using a short hadronization time in the model best describes the trends of the data.

A semimicroscopic self-consistent quantum approach was developed recently to describe the inner crust structure of neutron stars within the Wigner-Seitz method and with the explicit inclusion of neutron and proton pairing correlations is used for finding the neutron drip point that separates the outer and inner crusts. The equilibrium configurations of the crust are examined in vicinity of the drip point and in the upper part of the inner crust, for the density region corresponding to average Fermi momenta $k_F=0.2÷0.5{\mathrm{fm}}^{-1}$.

With realistic HFB calculations, using the D1S Gogny force, we reveal a generic behavior of concentration of small sized Cooper pairs (2–3 fm) in the surface of superfluid nuclei. This study confirms and extends previous results given in the literature that use more schematic approaches.

We study the effects of Lorentz invariance on relativistic constituent quark model wave functions. The model nucleon wave function of Gross et al. (nucl-th/0606029) is constructed such that there is no orbital angular momentum and that the spin-dependent density is spherical. This model wave function is claimed to be manifestly covariant. We consider two possible interpretations of the nucleon wave function in an arbitrary reference frame. In the first, the seeming covariance of the matrix elements of the electromagnetic current arises from using the Breit frame. Matrix elements have a different appearance in any other frame. In the second interpretation, the electromagnetic current is covariant yet it is not consistent with the general structure required by QFT (e.g., the wave function of the incoming nucleon depends on the momentum of the outgoing nucleon and vice versa).

We have studied natural parity states in ${}^{26}\mathrm{Mg}$ via the ${}^{22}\mathrm{Ne}$(${}^6\mathrm{Li}$, $d$)${}^{26}\mathrm{Mg}$ reaction. Our method significantly improves the energy resolution of previous experiments and, as a result, we report the observation of a natural parity state in ${}^{26}\mathrm{Mg}$. Possible spin-parity assignments are suggested on the basis of published γ-ray decay experiments. The stellar rate of the ${}^{22}\mathrm{Ne}$($\alpha ,\gamma$)${}^{26}\mathrm{Mg}$ reaction is reduced and may give rise to an increase in the production of $s$-process neutrons via the ${}^{22}\mathrm{Ne}$($\alpha ,n$)${}^{25}\mathrm{Mg}$ reaction.

Neutron-induced background events occurring within a γ-ray detector in the ${}^{12}\mathrm{C}$($\alpha ,\gamma$)${}^{16}\mathrm{O}$ reaction study are discussed by comparing a spectrum taken by a NaI(Tl) detector with a pulsed α beam with that taken previously by a Ge detector using a continuous α beam. Both spectra contain such background events induced by neutrons from the $(\alpha ,n)$ reaction on ${}^{13}\mathrm{C}$ and/or ${}^9\mathrm{Be}$ contained in enriched ${}^{12}\mathrm{C}$ targets. These observations together with a calculated γ-ray spectrum of the neutron-induced reaction by Ge isotopes indicate the thus-produced background events, which would barely be reduced by using shield materials, become significant background in the ${}^{12}\mathrm{C}$($\alpha ,\gamma$)${}^{16}\mathrm{O}$ reaction study at low-α-beam energy.

Mass measurements on radionuclides along the potassium isotope chain have been performed with the ISOLTRAP Penning trap mass spectrometer. For ${}^{35}\mathrm{K}$ ($T_{1/2}=178$ ms) to ${}^{46}\mathrm{K}$ ($T_{1/2}=105$ s) relative mass uncertainties of $2\times {10}^{-8}$ and better have been achieved. The accurate mass determination of ${}^{35}\mathrm{K}$ ($\delta m=0.54$ keV) has been exploited to test the isobaric multiplet mass equation for the $A=35,T=3/2$ isospin quartet. The experimental results indicate a deviation from the generally adopted quadratic form.

Based on experimental data for axially symmetric well deformed nuclei it is shown that the “Grodzins product” of the energy of the $2_{\gamma }^{+}$ state with the $B(E2;2_{\gamma }^{+}\to 0_{\mathrm{g}.\mathrm{s}.}^{+})$ for the transition from the $2_{\gamma }^{+}$ state to the ground state is a relatively smooth function of $Z$ and $A$. It is shown also that a ratio of the mass coefficients for the γ-motion and for the rotational ground band extracted from the experimental data take the values in the limits 3–5. The implied large difference between the two mass coefficients means that the mass tensor of the Bohr Hamiltonian cannot be reduced to a scalar as it usually assumed.

Despite the fact that valuable experimental measures are still lacking, available nuclear data on nucleon-induced reactions open new opportunities to address either reaction mechanisms or nuclear interaction characteristics. In this work single and double differential cross sections of emitted particles are analyzed and compared with the experiment. It will be evidenced that these cross sections follow a precise hierarchy. The preequilibrium components of the spectra are built up by the dynamics of the reaction as well as by the properties of the nuclear interaction.

We interpret the scaling of the corrected elliptic flow parameter with respect to the corrected multiplicity, observed to hold in heavy ion collisions for a wide variety of energies and system sizes. We use dimensional analysis and power-counting arguments to place constraints on the changes of initial conditions in systems with different center of mass energy $\sqrt{s}$. Specifically, we show that a large class of changes in the (initial) equation of state, mean free path, and longitudinal geometry over the observed $\sqrt{s}$ are likely to spoil the scaling in $v_2$ observed experimentally. We therefore argue that the system produced at most Super Proton Synchrotron (SPS) and Relativistic Heavy Ion Collider (RHIC) energies is fundamentally the same as far as the soft and approximately thermalized degrees of freedom are considered. The “sQGP” (Strongly interacting Quark-Gluon Plasma) phase, if it is there, is therefore not exclusive to RHIC. We suggest, as a goal for further low-energy heavy ion experiments, to search for a “transition” $\sqrt{s}$ where the observed scaling breaks.

This paper reports measurements made using the technique of online nuclear orientation which reexamine the γ decay of isomeric ${}^{180}{\mathrm{Hf}}^{\mathrm{m}}$ and specifically the 501 keV $8^{-}$–$6^{+}$ transition. The irregular admixture of $E2$ to $M2/E3$ multipolarity in this transition, deduced from the forward-backward asymmetry of its angular distribution, has for decades stood as the prime evidence for parity mixing in nuclear states. The experiment, based on ion implantation of the newly developed mass-separated ${}^{180}{\mathrm{Hf}}^{\mathrm{m}}$ beam at the CERN online isotope mass separator (ISOLDE) facility into an iron foil maintained at millikelvin temperatures, produces higher degrees of polarization than were achieved in previous studies of this system. The value found for the $E2/M2$ mixing ratio, $\epsilon =-0.0324$(16)(19), is in close agreement with the previous published average value $\epsilon =-0.030$(2), in full confirmation of the presence of the irregular $E2$ admixture in the 501 keV transition. The temperature dependence of the forward-backward asymmetry has been measured over a more extended range of nuclear polarization than previously possible, giving further evidence for parity mixing of the $8^{-}$ and $8^{+}$ levels and the deduced $E2/M2$ mixing ratio.

The evidence on single proton energies in the Si isotopes is traced from $N=12$ to $N=28$ using available experimental data on binding energies, single proton transfer reactions, radioactive decay, and direct reaction studies with neutron-rich exotic beams. In addition to demonstrating the value of having information on single particle energies over a long sequence of isotopes, the data point out a significant discrepancy between theoretical and experimental results on the size of the $Z=14$ subshell closure in ${}^{34}\mathrm{Si}$, which is located on the boundary of the island of inversion.