We report four Σ's and three Λ's, in the 1500–1800 MeV region, as two meson–one baryon S-wave $(1/2){}^{+}$ resonances. We solve Faddeev equations in the coupled channel approach. The invariant mass of one of the meson-baryon pairs and that of the three particles have been varied and peaks in the squared three body $T$-matrix have been found very close to the existing $S=-1,J^P=1/2^{+}$ low lying baryon resonances. The input two-body $t$-matrices for meson-meson and meson-baryon interaction have been calculated by solving the Bethe-Salpeter equation with the potentials obtained in the chiral unitary approach.

The renormalization of the chiral $\mathit{np}$ interaction in the ${}^1{S}_0$ channel to next-to-next-to-next-to-leading order (N3LO) in Weinberg counting for the long-distance potential with one single momentum- and energy-independent counterterm is carried out. This renormalization scheme yields finite and unique results and is free of short-distance off-shell ambiguities. We observe good convergence in the entire elastic range below pion production threshold and find that there are some small physical effects missing in the purely pionic chiral $\mathit{NN}$ potential with or without inclusion of explicit Δ degrees of freedom. We also study the renormalizability of the standard Weinberg counting at next-to-leading order (NLO) and next-to-next-to-leading order (N2LO) when a momentum-dependent polynomial counterterm is included. Our numerical results suggest that the inclusion of this counterterm does not yield a convergent amplitude (at NLO and N2LO).

Low-frequency $K^{\pi }=0^{+}$ states in deformed neutron-rich nuclei are investigated by means of the quasiparticle-random-phase approximation based on the Hartree-Fock-Bogoliubov formalism in the coordinate space. We have obtained the very strongly collective $K^{\pi }=0^{+}$ modes not only in neutron-rich Mg isotope but also in Cr and Fe isotopes in $N=40$ region, where the onset of nuclear deformation has been discussed. It is found that the spatially extended structure of neutron quasiparticle wave functions around the Fermi level brings about a striking enhancement of the transition strengths. It is also found that the fluctuation of the pairing field plays an important role in generating coherence among two-quasiparticle excitations of neutron.

We consider the analyzing power on a spin-0 nuclear target. This observable is related to the imaginary part of the two-photon-exchange (box) diagram. We consider the contributions of elastic and inelastic intermediate states. The former requires knowledge of the elastic nuclear form factor, while the latter uses the optical theorem as input. The elastic contribution scales as the nuclear charge $Z$, while the inelastic contribution scales as the ratio of the atomic number and nuclear charge, $A/Z$. We provide estimates for ${}^4\mathrm{He}$ and ${}^{208}\mathrm{Pb}$, in the kinematics of existing or upcoming experiments. In both cases, we predict negative values for the analyzing power of a few parts per million, and the dominant contribution is due to inelastic intermediate states. The analyzing power can contribute a substantial systematic error in parity-violating experiments.

We study the effects of strong magnetic fields on antikaon condensation in neutron star matter using the quark-meson coupling (QMC) model. The QMC model describes a nuclear many-body system as nonoverlapping MIT bags in which quarks interact through the self-consistent exchange of scalar and vector mesons in the mean-field approximation. It is found that the presence of strong magnetic fields alters the threshold density of antikaon condensation significantly. The onset of $K^{-}$ condensation stronger depends on the magnetic field strength, and it even shifts beyond the threshold of ${\overline{K}}^0$ condensation for sufficiently strong magnetic fields. In the presence of strong magnetic fields, the equation of state (EOS) becomes stiffer in comparison with the field-free case. The softening of the EOS by antikaon condensation also depends on the magnetic field strength, and it becomes less pronounced with increasing magnetic field strength. The results of the QMC model are compared with those obtained in a relativistic mean-field (RMF) model, and we find there are quantitative differences between the results of the QMC and RMF models.

The $\mathit{SD}$-pair shell model is employed to study ${}^{126}\mathrm{Xe}$ and ${}^{128}\mathrm{Ba}$. The results show that the spectra and electromagnetic transition strengths can be nicely described in terms of a three-parameter Hamiltonian. In our previous paper, we got a conclusion that the $\mathit{SD}$-pair approximation improves with the number of $\mathit{SD}$ pairs $N$. This work shows that this conclusion can be extrapolated to the case with $N=5$.

It is shown that a measurement of the analyzing power obtained with linearly polarized γ-rays and an unpolarized target can provide an indirect determination of two physical quantities. These are the Gerasimov-Drell-Hearn (GDH) sum rule integrand for the deuteron and the sum rule integrand for the forward spin polarizability (${\gamma }_0$) near photodisintegration threshold. An analysis of data for the $d(\overrightarrow{\gamma },n)p$ reaction and other experiments is presented. A fit to the world data analyzed in this manner gives a GDH integral value of $-603\pm 43\mu$b between the photodisintegration threshold and 6 MeV. This result is the first confirmation of the large contribution of the ${}^1{S}_0(M1)$ transition predicted for the deuteron near photodisintegration threshold. In addition, a sum rule value of 3.75±0.18 fm${}^4$ for ${\gamma }_0$ is obtained between photodisintegration threshold and 6 MeV. This is a first indirect confirmation of the leading-order effective field theory prediction for the forward spin-polarizability of the deuteron.

In the meson-theoretical potential model for the study of the nonmesonic decay rates and asymmetries of hypernuclei, for the first time, the axial-vector $a_1$ meson ($J^{\mathrm{PC}}=1^{++},m_{a_1}=1230\mathrm{MeV}$) is introduced. The $a_1$ meson is the chiral partner of the ρ meson and has been treated in the meson-pair exchange framework as $\rho \pi /a_1$ and $\sigma \pi /a_1$. This is analogous to the treatment of ρ and σ exchange in our model. The $a_1$-meson exchange is found to give remarkable modifications of the parity-conserving decay potentials $({}^{1,3}S\to {}^{1,3}S$ and ${}^3{S}_1\to {}^3{D}_1)$ at short range $r⩽1$ fm. As a result, the calculated intrinsic asymmetry parameter ${\alpha }_{\Lambda }$ for ${}_{\Lambda }^5\mathrm{He}$ becomes very small and positive in good agreement with the recent high-quality experimental data. The calculated small values of ${\alpha }_{\Lambda }$ are well compared with the data for ${}_{\Lambda }^{11}\mathrm{B}$ and ${}_{\Lambda }^{12}\mathrm{C}$ within error bars. The inclusion of the $a_1$ meson also improves the ${\Gamma }_n/{\Gamma }_p$ ratios and leads to a consistent explanation for the existing nonmesonic weak decay data of the light Λ hypernuclei $(A⩽12)$. The results calculated in the $\pi +2\pi /\rho +2\pi /\sigma +\omega +K+\rho \pi /a_1+\sigma \pi /a_1$ exchange interaction model are presented together with the estimates without $a_1$. Also, the derivation of the expression for the proton asymmetry is described in some detail to elucidate the calculation procedures and phase conventions.

We determine the decoupling surfaces for the hydrodynamic description of heavy ion collisions at RHIC and LHC by comparing the local hydrodynamic expansion rate with the microscopic pion-pion scattering rate. The pion $p_T$ spectra for nuclear collisions at BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC) are computed by applying the Cooper-Frye procedure on the dynamical-decoupling surfaces and compared with those obtained from the constant-temperature freeze-out surfaces. Comparison with RHIC data shows that the system indeed decouples when the expansion rate becomes comparable with the pion scattering rate. The dynamical decoupling based on the rates comparison also suggests that the effective decoupling temperature in central heavy ion collisions remains practically unchanged from RHIC to LHC.

We report on the observed differences in production rates of strange and multistrange baryons in Au+Au collisions at $\sqrt{s_{\mathit{NN}}}=200$ GeV compared to $p+p$ interactions at the same energy. The strange baryon yields in Au+Au collisions, when scaled down by the number of participating nucleons, are enhanced relative to those measured in $p+p$ reactions. The enhancement observed increases with the strangeness content of the baryon, and it increases for all strange baryons with collision centrality. The enhancement is qualitatively similar to that observed at the lower collision energy $\sqrt{s_{\mathit{NN}}}=17.3$ GeV. The previous observations are for the bulk production, while at intermediate $p_T,1<p_T<4$ GeV/$c$, the strange baryons even exceed binary scaling from $p+p$ yields.

Modest spin states in neutron-rich ${}^{187}\mathrm{W}$ have been populated by using a ${}^{186}\mathrm{W}$(${}^{18}\mathrm{O}$,${}^{17}\mathrm{O}$) one-neutron transfer reaction. Negative-parity bands previously known are extended to higher spin, and two positive-parity bands are newly identified. Configurations based on ν i${}_{13/2}$ orbitals are assigned to these bands from an analysis of the level energy systematics as well as the g factors derived from in-band branching ratios.

The existence of long lived superheavy nuclei (SHN) is controlled mainly by spontaneous fission and α-decay processes. According to microscopic nuclear theory, spherical shell effects at $Z=114$, 120, 126 and $N=184$ provide the extra stability to such SHN to have long enough lifetime to be observed. To investigate whether the so-called “stability island” could really exist around the above $Z$, $N$ values, the α-decay half-lives along with the spontaneous fission and β-decay half-lives of such nuclei are studied. The α-decay half-lives of SHN with $Z=102$–120 are calculated in a quantum tunneling model with DDM3Y effective nuclear interaction using $Q_{\alpha }$ values from three different mass formulas prescribed by Koura-Uno-Tachibana-Yamada (KUTY), Myers-Swiatecki (MS), and Muntian-Hofmann-Patyk-Sobiczewski (MMM). Calculation of spontaneous fission (SF) half-lives for the same SHN are carried out using a phenomenological formula and compared with SF half-lives predicted by Smolanczuk et al. A possible source of discrepancy between the calculated α-decay half-lives of some nuclei and the experimental data of GSI, JINR-FLNR, RIKEN, is discussed. In the region of $Z=106$–108 with $N~$ 160–164, the β-stable SHN ${}_{106}^{268}{\text{Sg}}_{162}$ is predicted to have highest α-decay half-life ($T_{\alpha }~3.2$ h) using $Q_{\alpha }$ value from MMM. Interestingly, it is much greater than the recently measured $T_{\alpha }$ ($~22$ s) of deformed doubly magic ${}_{108}^{270}{\text{Hs}}_{162}$ nucleus. A few fission-survived long-lived SHN which are either β-stable or having large β-decay half-lives are predicted to exist near ${}^{294}{110}_{184}$, ${}^{293}{110}_{183}$, ${}^{296}{112}_{184}$, and ${}^{298}{114}_{184}$. These nuclei might decay predominantly through α-particle emission.

A complete set of Wolfenstein parameters ($D_{i^{\text{'}}j}$), induced polarizations ($P$), and analyzing powers ($A_y$) have been measured for ($p,2p$) reactions on ${}^6\mathrm{Li}$, ${}^{12}\mathrm{C}$, and ${}^{40}\mathrm{Ca}$ targets in order to investigate possible nuclear medium effects on the nucleon-nucleon ($\mathit{NN}$) interaction. Most of these observables show significant reductions from the values for proton-proton scattering as monotonic functions of the nuclear density relevant to these reactions. The reductions of these $D_{i^{\text{'}}j}$ are reasonably reproduced by nonrelativistic plane-wave and distorted-wave calculations based on the impulse approximation, demonstrating that these suppressions are attributed to changes of the two body kinematics due to the finite separation energies of these reactions, while the reductions of $A_y$ and $P$ are much more prominent than the calculations. The relativistic calculations, which partly explain the $A_y$ and $P$ reductions, cannot reproduce the $D_{i^{\text{'}}j}$ data, but all the data are consistently reproduced when the parameters of the $\mathit{NN}$ interaction in a meson exchange model are renormalized, suggesting possible modifications of the $\mathit{NN}$ interaction by the surrounding nuclear medium.

We find that a collective flow model can successfully be used to analyze charged particle distributions at AGS and lower SPS ($E_{\mathit{NN}}^{\mathrm{lab}}$ less than 20 GeV in the laboratory frame) but fails at RHIC. The tail of the distribution of charged particles at RHIC has a jump from the collective flow model calculation as the energy increases. In this paper a thermalization component model is presented based on collective flow to study the multiplicity distributions at RHIC. It is realized that the region of phase space of collective flow can reflect that of the thermalization region. By comparing the contributions of particle production from the thermalization region at different energies and different centralities, we can deepen our study on collective movement at RHIC.

We extend previous relativistic mean-field (RMF) calculations of multi-$\overline{K}$ nuclei, using vector boson fields with SU(3) PPV coupling constants and scalar boson fields constrained phenomenologically. For a given core nucleus, the resulting $\overline{K}$ separation energy $B_{\overline{K}}$, as well as the associated nuclear and $\overline{K}$-meson densities, saturate with the number κ of $\overline{K}$ mesons for $\kappa >{\kappa }_{\mathrm{sat}}~10$. Saturation appears robust against a wide range of variations, including the RMF nuclear model used and the type of boson fields mediating the strong interactions. Because $B_{\overline{K}}$ generally does not exceed 200 MeV, it is argued that multi-$\overline{K}$ nuclei do not compete with multihyperonic nuclei in providing the ground state of strange hadronic configurations and that kaon condensation is unlikely to occur in strong-interaction self-bound strange hadronic matter. Last, we explore possibly self-bound strange systems made of neutrons and ${\overline{K}}^0$ mesons, or protons and $K^{-}$ mesons, and study their properties.

It is shown that the data on the pion charge form factor admit the possibility for a substantial sea-quark component in the pion wave function. If the charge form factor is calculated with instant form kinematics in a constituent quark model that is extended to include explicit $(q\overline{q}){}^2$ components in the pion wave function, that component will give the dominant contribution to the calculated ${\pi }^{+}$ charge form factor at large values of momentum transfer. The present experimental values $Q^2$ can be described fairly well with $(q\overline{q}){}^2$ component admixtures of up to 50%. The sensitivity of the calculated ${\pi }^{+}$ charge form factor to whether one of the quarks or one of the antiquarks is taken to be in the $P$ state is small.

An important constraint in developing models of $p$-process nucleosynthesis is that the abundances of many of the $p$-process nuclides are not well known. A recent review of the $p$-process has identified six $p$-process nuclides that are of particular significance to $p$-process theorists [M. Arnould and S. Goriely, Phys. Rep. 384, 1 (2003)]. These nuclides are ${}^{92,94}\mathrm{Mo}$, ${}^{96,98}\mathrm{Ru}$, ${}^{138}\mathrm{La}$, and ${}^{180}\mathrm{Ta}$${}^{\mathrm{m}}$. The absence of accurate abundances for these isotopes is due to the fact that the isotopic composition of the elements concerned have not been corrected for isotope fractionation induced by the thermal ionization mass spectrometric instruments used to measure them. To remedy this deficiency, a VG 354 mass spectrometer was calibrated using gravimetric mixtures of enriched isotopes to enable the absolute isotopic compositions of these elements to be obtained. Although the isotopic abundances of ${}^{92,94}\mathrm{Mo}$, ${}^{138}\mathrm{La}$, and ${}^{180}\mathrm{Ta}$${}^{\mathrm{m}}$ have previously been reported, the absolute abundances of ${}^{96,98}\mathrm{Ru}$ are reported for the first time in this article, with a significant reduction in the magnitude of the values as compared to existing abundances.

We study the world data on elastic electron-helium scattering to determine the ${}^4\mathrm{He}$ charge root-mean-square radius. A precise value for this radius is needed as a reference for a number of ongoing studies in nuclear and atomic physics.

Prima facie the systematic implementation of corrections to the rainbow-ladder truncation of QCD's Dyson-Schwinger equations will uniformly reduce in magnitude those calculated mass-dimensioned results for pseudoscalar and vector meson properties that are not tightly constrained by symmetries. The aim and interpretation of studies employing rainbow-ladder truncation are reconsidered in this light.

The ${}^{13}\mathrm{C}$($\alpha ,n$)${}^{16}\mathrm{O}$ reaction is considered the main neutron source for the s process in low mass asymptotic giant branch (AGB) stars. In the Gamow peak, the cross section sensitively depends on the $1/2^{+}$ subthreshold state of ${}^{17}\mathrm{O}$ ($E_x=6.356$ MeV). In this work, we determined the astrophysical $S$ factor through an evaluation of the α spectroscopic factor and the corresponding asymptotic normalization factor (ANC) of the 6.356 MeV state using the transfer reaction ${}^{13}\mathrm{C}$(${}^7\mathrm{Li}$,$t$)${}^{17}\mathrm{O}$ at two different incident energies. Our result confirms that the contribution of the $1/2^{+}$ state is dominant at astrophysical energies. Our reaction rate at $T=0.09$ GK is slightly lower than the value adopted in the Nuclear Astrophysics Compilation of REaction rates (NACRE), but two times larger than the one obtained in a recent ANC measurement.