We study the origin of the resonances associated with pole singularities of the scattering amplitude in the chiral unitary approach. We propose a “natural renormalization” scheme using the low-energy interaction and the general principle of the scattering theory. We develop a method to distinguish dynamically generated resonances from genuine quark states [Castillejo-Dalitz-Dyson (CDD) poles]  using the natural renormalization scheme and phenomenological fitting. Analyzing physical meson-baryon scatterings, we find that the $\Lambda (1405)$ resonance is largely dominated by the meson-baryon molecule component. In contrast, the $N(1535)$ resonance requires a sizable CDD pole contribution, while the effect of the meson-baryon dynamics is also important.

The reaction ${\pi }^{-}p\to \eta n$ is investigated within a dynamical coupled-channels model of meson production reactions in the nucleon resonance region. The meson baryon channels included are $\pi N,\eta N,\pi \Delta ,\sigma N$, and $\rho N$. The nonresonant meson-baryon interactions of the model are derived from a set of Lagrangians by using a unitary transformation method. One or two excited nucleon states in each of $S,P,D$, and $F$ partial waves are included to generate the resonant amplitudes. Data of the ${\pi }^{-}p\to \eta n$ reaction from threshold up to a total center-of-mass energy of about 2 GeV are satisfactorily reproduced and the roles played by the following nine nucleon resonances are investigated: $S_{11}(1535),S_{11}(1650),P_{11}(1440),P_{11}(1710),P_{13}(1720),D_{13}(1520),D_{13}(1700),D_{15}(1675)$, and $F_{15}(1680)$. The reaction mechanism and the predicted $\eta N$ scattering length are discussed.

The properties of kaons and antikaons and their modifications in isospin asymmetric nuclear matter are investigated using a chiral SU(3) model. These isospin-dependent medium effects are important for asymmetric heavy-ion collision experiments and will be especially relevant for the neutron-rich heavy-ion collision experiments in the future accelerator facility GSI Facility for Antiproton and Ion Research (GSI-FAIR). In the present work, the medium modifications of the energies of the kaons and antikaons, within the asymmetric nuclear matter, arise because of the interactions of kaons and antikaons with the nucleons and scalar mesons. The values of the parameters in the model are obtained by fitting the saturation properties of nuclear matter and kaon-nucleon scattering lengths for $I=0$ and $I=1$ channels. Furthermore, the isovector and isoscalar pion-nucleon scattering lengths are calculated within the chiral effective model and compared with earlier results from the literature. The kaon-nucleon and pion-nucleon $\Sigma$ coefficients are also calculated within the present chiral SU(3) model.

We discuss the open charm production in the peripheral reactions $\overline{p}p\to {\overline{Y}}_c{Y}_c$ and $\overline{p}p\to M_c{\overline{M}}_c$, where $Y_c$ and $M_c$ stand for ${\Lambda }_c^{+},{\Sigma }_c^{+}$ and $D,D^{*}$, respectively, at $\sqrt{s}\lesssim 15$ GeV, which corresponds to the energy range of FAIR. Our consideration is based on the topological decomposition of the planar quark and diquark diagrams, which allows us to estimate consistently meson and baryon exchange trajectories and energy scale parameters as well. The spin dependance is determined by the effective interaction of the lowest exchanged resonance. Unknown parameters are fixed by an independent analysis of open strangeness production in $\overline{p}p\to \overline{Y}Y$ and $\overline{p}p\to \overline{K}K$ reactions and of SU(4) symmetry. We present the corresponding cross sections and longitudinal double-spin asymmetries for exclusive binary reactions with open charm mesons and baryons in the final state. The polarization observables have a nontrivial $t$ and $s$ dependence that is sensitive to details of the open charm production mechanism.

The analysis of the JLab proton polarization data on the ratio ${\mu }_p{G}_{\mathit{Ep}}(t)/G_{\mathit{Mp}}(t)$ in the framework of the unitary and analytic model of nucleon electromagnetic structure implicates surprising nondipole behavior of the proton electric form factor $G_{\mathit{Ep}}(t)$ in the space-like region with the zero around the momentum transfer squared value $t=-Q^2=-13\hspace{0.5em}{\mathrm{GeV}}^2$. This result differs from the unpolarized cross-section measurements giving the dipole behavior of $G_{\mathit{Ep}}(t)$ by means of the Rosenbluth technique. Recent investigations demonstrate that inclusion of a two-photon mechanism could solve the problem, which plays an important role for the unpolarized cross section, but it is negligible for the polarization ratio. Here, investigating a size of a difference in a prediction of the deuteron elastic structure functions $A(t),B(t)$ by both, the nondipole and the old dipole, behaviors of $G_{\mathit{Ep}}(t)$ in space-like region through the nonrelativistic impulse approximation, we have come to the conclusion that the two-photon mechanism plays much less of a role for the unpolarized electron-deuteron elastic scattering than for the unpolarized electron-proton elastic scattering.

Parity-violating nuclear force, as may be accessed from parity-violation studies in nuclear systems, represents an area of nonleptonic weak interactions that has been the subject of experimental investigations for several decades. In the simple meson-exchange picture, a parity-violating nuclear force may be parametrized as arising from the exchange of $\pi ,\rho ,\omega$, or other mesons with strong meson-nucleon coupling at one vertex and weak parity-violating meson-nucleon coupling at the other vertex. The QCD sum rule method allows for a fairly complicated, but nevertheless straightforward, leading-order loop-contribution determination of the various parity-violating $\mathrm{MNN}$ couplings starting from QCD (with the nontrivial vacuum) and Glashow-Salam-Weinberg electroweak theory. We continue our earlier investigation of the parity-violating $\pi \mathit{NN}$ coupling (by Henley, Hwang, and Kisslinger) to other parity-violating couplings. Our predictions are in reasonable overall agreement with the results estimated on phenomenological grounds, such as in the now classic paper of Desplanques, Donoghue, and Holstein, in the global experimental fit of Adelberger and Haxton, or the effective field theory thinking of Ramsey-Musolf and Page.

We provide convenient parametrizations of the high-density nuclear equation of state obtained within the Brueckner-Hartree-Fock approach using different modern nucleon-nucleon potentials together with compatible microscopic nuclear three-body forces. The corresponding neutron star mass-radius relations are also presented.

A statistical model calculation for the decay of a compound nucleus is presented where the compound nuclear spin dependence of the Kramers modified fission width is included. Specifically, the spin dependences of the frequencies of the harmonic oscillator potentials osculating the rotating liquid-drop model potential at equilibrium and saddle regions are considered. Results for the ${}^{16}\mathrm{O}+{}^{208}\mathrm{Pb}$ system show that the energy dependence of the dissipation strength extracted from fitting experimental data is substantially reduced when the spin dependence of the frequencies is properly taken into account.

We examine the electric and magnetic strange form factors of the nucleon in the pseudoscalar-vector SU(3) Skyrme model, with special emphasis on the effects of isospin symmetry breaking (ISB). It is found that ISB has a nontrivial effect on the strange vector form factors of the nucleon and its contribution to the nucleon strangeness is significantly larger than one might naively expect. Our calculations and discussions may be of some significance for the experimental extraction of the authentic strangeness.

The mixing of di-neutron components in ${}^8\mathrm{He}$ is studied. The ground state of ${}^8\mathrm{He}$ corresponds to the sub-closed-shell configuration of the spin-orbit favored orbits ($p_{3/2}$) for the neutrons, and the shell-model-like configuration is considered to be dominant. However, ${}^8\mathrm{He}$ is a drip-line nucleus with a two-neutron separation energy of 2.1 MeV, and the di-neutron configuration, which is a characteristic feature of the weakly bound systems, mixes in the ground state. The motion of four neutrons around the ${}^4\mathrm{He}$ core is solved by superposing the wave functions of antisymmetrized molecular dynamics. The mixing of di-neutron configurations is estimated by coupling the THSR (Tohsaki-Horiuchi-Schuck-Röpke) wave function, which successfully describes the α-condensed state of light nuclei.

The property of extended longitudinal scaling of rapidity distributions was noticed recently over a broad range of beam energies. It is shown here that this property is consistent with predictions of the statistical thermal model up to the highest BNL Relativistic Heavy Ion Collider (RHIC) beam energies; however, we expect that at CERN Large Hadron Collider (LHC) energies the rapidity distribution of produced particles will violate extended longitudinal scaling.

We report on the use of the one-proton knockout reaction from ${}^{44}\mathrm{S}$ to determine the location of $d_{5/2}$ proton strength in neutron-rich ${}^{43}\mathrm{P}$. The results are used to test two shell-model frameworks with different pictures of the evolution of single-proton energies along the $N=28$ isotones near the neutron dripline. We observe a concentration of $d_{5/2}$ proton hole strength near 1 MeV in excitation energy. This result favors the recent shell-model interaction of Utsuno et al. [Eur. Phys. J. Spec. Top. 150, 187 (2007)] and provides additional evidence for an oblate shape for ${}^{42}\mathrm{Si}$.

The $E2$ component of the ${}^{12}\mathrm{C}(\alpha ,\gamma ){}^{16}\mathrm{O}$ cross section is investigated in two ways: by a microscopic cluster model, and by $R$-matrix fits. The $\alpha {+}^{12}\mathrm{C}$ microscopic calculation is performed in the framework of the generator coordinate method (GCM) by including all ${}^{12}\mathrm{C}$ states ($T=0$) within the $p$ shell. Using different nucleon-nucleon interactions we find $S_{E2}(300\hspace{0.5em}\mathrm{keV})\approx 50$ keV $·$ b for ground-state transitions. We also study cascade transitions to the $0_2^{+}$ and $2_1^{+}$ excited states of ${}^{16}\mathrm{O}$. Then the $S$-factor is analyzed in the phenomenological $R$-matrix theory. We show that the background term plays a crucial role, and cannot be determined without ambiguity. Using the experimental phase shifts and capture cross sections, only an upper limit on the extrapolated $S$ factor can be obtained [$S_{E2}(300\hspace{0.5em}\mathrm{keV})<190$ keV $·$ b]. To constrain the $R$-matrix analysis, we use the GCM asymptotic normalization constant (ANC) of the $2_1^{+}$ level, well known to be a cluster state. This procedure strongly reduces the uncertainties on the $R$-matrix fit, and we end up with a recommended value of $S_{E2}(300\hspace{0.5em}\mathrm{keV})=42\pm 2$ keV $·$ b. We show that ANC values derived from indirect methods are not consistent with the ${}^{12}\mathrm{C}(\alpha ,\gamma ){}^{16}\mathrm{O}$ cascade transitions to the $2_1^{+}$ state, and suggest that a remeasurement of this cross section is desirable.

Spin distributions of various reaction products populated via complete and/or incomplete fusion of ${}^{16}\mathrm{O}$ with ${}^{169}\mathrm{Tm}$ have been measured at projectile energy $\approx 5.6$ MeV/nucleon. Particle ($Z=1,2$) γ-coincidences have been employed to achieve the information about involved reaction modes on the basis of their entry state spin populations. The experimentally measured spin distributions for incomplete fusion products have been found to be distinctly different than those observed for complete fusion products. The driving input angular momenta associated with incomplete fusion products have been found to be relatively higher than complete fusion products, and increases with direct α-multiplicity. It has also been observed that incomplete fusion products are less fed and/or the population of lower spin states are strongly hindered, while complete fusion products indicating strong feeding over a broad spin range.

We perform a fully relativistic calculation of the ${}^2\mathrm{H}$$(e,e^{\text{'}}p)n$ reaction in the impulse approximation. We employ the Gross equation to describe the deuteron ground state, and we use the SAID parametrization of the full $\mathit{NN}$ scattering amplitude to describe the final state interactions (FSIs). We include both on-shell and positive-energy off-shell contributions in our FSI calculation. We show results for momentum distributions and angular distributions of the differential cross section, as well as for various asymmetries. We identify kinematic regions where various parts of the FSIs are relevant, and discuss the theoretical uncertainties connected with calculations at high missing momenta.

A novel higher order theory of relaxation of heat and viscosity is proposed based on corrections to the traditional treatment of the relativistic energy density. In the framework of generalized Bjorken scaling solution to accelerating longitudinal flow we point out that the energy flux can be consequently set to zero in the stationary case, independently of the choice of a specific local rest frame, like the Landau-Lifshitz or Eckart one. We investigate and compare several cooling and reheating scenarios for the quark gluon plasma within this approach.

The strange quark contribution to the vector and axial form factors of the nucleon has been determined for momentum transfers in the range $0.45<Q^2<1.0$ GeV${}^2$. The results are obtained via a combined analysis of forward-scattering, parity-violating elastic $\overrightarrow{e}p$ asymmetry data from the G0 and HAPPEx experiments at Jefferson Lab and elastic $\nu p$- and $\overline{\nu }p$-scattering data from Experiment 734 at Brookhaven National Laboratory. The parity-violating asymmetries measured in elastic $\overrightarrow{e}p$ scattering at forward angles establish a relationship between the strange vector form factors $G_E^s$ and $G_M^s$, with little sensitivity to the strange axial form factor $G_A^s$. However, elastic neutrino scattering at low $Q^2$ is dominated by the axial form factor, with some significant sensitivity to the vector form factors as well. Combination of the two data sets allows the simultaneous extraction of $G_E^s,G_M^s$, and $G_A^s$ over a significant range of $Q^2$ for the very first time. The $Q^2$ dependence of the strange axial form factor suggests that the strange quark contribution to the proton spin, $\Delta s$, is negative.

We study the electroproduction of $\rho$ mesons in nuclei at intermediate energies, deriving a treatment of the energy lost by the $\rho$ in each step of multiple scattering. This enables a close match between calculations and the experimental kinematic conditions. A standard Glauber calculation is presented, and then the effects of color-transparency are included. The influence of poor experimental resolution on the extracted transparency is assessed. The effects of $\rho$ meson decay inside the nucleus are examined, and are typically about 5% at most. This effect disappears rapidly as $Q^2$ increases from about 1 to 3 ${\mathrm{GeV}}^2$, causing a rise in the transparency that is not attributable to color transparency. The size of color transparency effects for C and Fe nuclei is studied for values of $Q^2$ up to 10 ${\mathrm{GeV}}^2$. The detailed results depend strongly on the assumed value of the $\rho N$ cross section. The overall effects of color transparency are greater than about 10% for both nuclear targets if $Q^2$ is greater than about 5 ${\mathrm{GeV}}^2$.

Supernovae of Type II is a phenomenon that occurs at the end of the evolution of massive stars when the iron core of the star exceeds a mass limit. After the collapse of the core under gravity the shockwave alone does not succeed in expelling the mass of the star and in this sense the role of neutrinos is the most important mechanism to do so. During the emission of neutrinos flavor conversion is possible, related the phenomenon of oscillations, which however depends directly on the particular density profile of the medium. In this paper we present results of numerical simulations of neutrino flavor conversion in supernovae after bounce. The probabilities of survival for a given flavor in a complete three-flavors framework is estimated through an algorithm which conserves unitarity to a high degree of accuracy. The sensitivity of the results to the different adopted models for the supernova structure is examined in detail demonstrating how the neutrino signal could be used to check the validity of models.