Chiral partner candidate bands have been found in ${}^{103}\mathrm{Rh}$. As a result of this observation, a special quartet of neighboring chiral candidate nuclei can be investigated for the first time. With this quartet identified, a comparison between the behavior of the nearly degenerate doublet bands belonging to the same core but to different valence quasiparticle configurations, as well as belonging to different cores but to the same valence quasiparticle configuration, becomes possible. The comparison shows that the energy separation of these doublet band structures depends mainly on the core properties and to a lesser extent on the valence quasiparticle coupling. This observation sets up new criteria for the explanations of the band doublings, restricting the possible scenarios and providing new information on the characteristics of the underlying mechanism; it is in qualitative agreement with the chiral scenario.

We describe the use of the density matrix renormalization group method as a means of approximately solving large-scale nuclear shell-model problems. We focus on an angular-momentum-conserving variant of the method and report test results for the nucleus ${}^{48}\mathrm{Cr}$. The calculation is able to reproduce both the ground-state energy and the energy of the first excited state, by diagonalizing matrices much smaller than those of the full shell model.

We study cold dilute neutron matter on the lattice using an effective field theory. We work in the unitary limit in which the scattering length is much larger than the interparticle spacing. In this article we focus on the equation of state at temperatures above the Fermi temperature and compare lattice simulations to the virial expansion on the lattice and in the continuum. We find that in the unitary limit lattice discretization errors in the second virial coefficient are significantly enhanced. As a consequence the equation of state does not show the universal scaling behavior expected in the unitary limit. We suggest that scaling can be improved by tuning the second virial coefficient rather than the scattering length.

The specific heat, mean hadronic mass excited and its fluctuation are connected to particle production yields and properties of baryon and electric charge chemical potentials (value, slope and curvature). A possible divergence of the specific heat as 1/($T_0-T){}^2$ is discussed. A Hagedorn model with $\rho ~m^{-\tau }\exp ({\beta }_{h}m)$ is studied and restriction on τ are analyzed. Limitations imposed by a Q-g transition are mentioned.

Recently, we have reported a measurement of the neutron-deuteron elastic scattering differential cross section at 95 MeV. In the present work, the previous results are confirmed with an independent measurement performed with another setup. The new data cover the full angular distribution by combining neutron detection and deuteron detection, and have an unprecedented precision in the region of the cross-section minimum, where three-nucleon forces are expected to be significant. The effect already identified in the previous measurement is clearly seen in the present data, which agree well with theoretical descriptions including three-nucleon forces.

The partition function by means of the static path approximation (SPA) plus the random-phase approximation (RPA) treatment can be written as a contour integral form without solving the RPA equations for a separable interaction. This method is an efficient way to evaluate numerically the partition function for realistic calculations. As an illustration, we adopt the pairing model at finite temperature.

The $\beta$-decay of ${}^{18}\mathrm{N}$ has been studied using $\beta \text{−}n$ and $\beta \text{−}\gamma$ coincidence methods. The ${}^{18}\mathrm{N}$ ions were produced by the fragmentation of the $E/A=68.8$ MeV ${}^{22}\mathrm{Ne}$ beam on a thick beryllium target. A newly constructed neutron detector system with wide energy detection range and low-energy detection threshold was used. The 619 ± 2 ms half-life of the ${}^{18}\mathrm{N}$ $\beta$-decay was found to be in very good agreement with the previous measurements. Transitions to 11 $\beta$-delayed neutron emitting states in ${}^{18}\mathrm{O}$ have been observed with a total branching ratio of 6.98 ± 1.46%. The Gamow-Teller $\beta$-decay strengths of ${}^{18}\mathrm{N}$ to these levels were deduced and compared with the shell model calculations. The intensities of the strong $\gamma$-ray transitions in ${}^{18}\mathrm{O}$ were found to be consistent with recent work.

A search for the fourfold forbidden β decay of ${}^{113}$Cd has been performed with CdZnTe semiconductors. With 0.86 kg · d of statistics a half-life for the decay of $T_{1/2}=[8.2\pm 0.2(\mathrm{stat}.){}_{-1.0}^{+0.2}(\mathrm{sys}.)]\times {10}^{15}$ yr has been obtained. This is in good agreement with published values. A comparison of the spectral shape with the one given on the Table of Isotopes Web page shows a severe deviation.

Nuclear ground and excited state properties are described by using parameter systematics on mass and level density formulas. The formulas are based on an analytical expression of the single-particle state density by introducing the shell-pairing correlation in a new way. Main features are the shell, pairing, and deformation effects on the droplet model near the ground state, which are washed out at higher excitation energies. The main aim of the paper is to provide in the analytical framework the improved energy dependent shell, pairing, and deformation corrections generalized to the collective enhancement factors, which offer a systematic prescription over a great number of nuclear reactions. The new formulas are shown to be in close agreement with not only the empirical nuclear mass data but also the measured slow neutron resonance spacings and experimental systematics observed in the excitation energy dependent properties.

The low-energy level structure of ${}^{25}\mathrm{Ne}$ has been investigated following the ${\beta }^{-}$ decay of ${}^{25}\mathrm{F}$. Beta-delayed γ spectroscopy revealed new γ transitions in ${}^{25}\mathrm{Ne}$ at 1234, 1622, and 2090 keV. The new transitions were placed in the level scheme of ${}^{25}\mathrm{Ne}$ in accordance with the observed $\gamma \text{−}\gamma$ coincidences. The total ${\beta }^{-}$ decay strength has been accounted for. The spins and parities of the first two excited states could be ascertained by comparison with a shell model calculation and the literature. The half-life for ${}^{25}\mathrm{F}$ decay was also remeasured using fragment-$\beta \text{−}\gamma$ correlations, revealing a value of 90 ± 9 ms. Comparison with shell model calculations are indicative of a wider $N=16$ gap as compared to the stable nuclei.

A new form of the binding energy formula of heavy nuclei with $Z\ge 90$ is proposed where new terms beyond the standard Bethe and Weizsäcker formula are introduced by analytical expressions. This can be considered an interesting development of the Bethe and Weizsäcker mass formula for heavy nuclei with $Z\ge 90$. Two versions of the formulae are presented. The first version of the formula can reproduce the 117 known binding energies of nuclei with $Z\ge 90$ and $N\ge 140$ with an average deviation $0.118$ MeV. This is the first time that the binding energies of heavy nuclei with $Z\ge 90$ and $N\ge 140$ can be calculated very accurately by a formula with only seven parameters. The binding energies, α-decay energies, and α-decay half-lives of unknown superheavy nuclei are predicted. The second version of the formula is obtained by fitting the 181 data of nuclei with $Z\ge 90$ with nine parameters and good agreement with experimental binding energies is also reached for all nuclei with $Z\ge 90$.

Two-level boson systems displaying a quantum phase transition from a spherical (symmetric) to a deformed (broken) phase are studied. A formalism to diagonalize Hamiltonians with $O(2L+1)$ symmetry for large number of bosons is worked out. Analytical results beyond the simple mean-field treatment are deduced by using the continuous unitary transformations technique. In this scheme, a $1/N$ expansion for different observables is proposed and allows one to compute the finite-size scaling exponents at the critical point. Analytical and numerical results are compared and reveal the power of the present approach to compute the finite-size corrections in such a context.

In this paper we obtain number of states with a given spin I and a given isospin T for systems with three and four nucleons in a single-j orbit, by using sum rules of six-j and nine-j symbols obtained in earlier works.

In this paper we investigate isospin transport mechanisms in semiperipheral collisions at Fermi energies. The effects of the formation of a low density region (neck) between the two reaction partners and of preequilibrium emission on the dynamics of isospin equilibration are carefully analyzed. We clearly identify two main contributions to the isospin transport: isospin diffusion due to the $N/Z$ ratio and isospin drift due to the density gradients. Both effects are sensitive to the symmetry part of the nuclear equation of state (EOS), in particular to the value and slope around saturation density.

Data on low-$p_T$ hadronic spectra are widely regarded as evidence of a hydrodynamic expansion in nucleus-nucleus collisions. In this interpretation, different hadron species emerge from a common medium that has built up a strong collective velocity field. Here we show that the existence of a collective flow field implies characteristic modifications of high-$p_T$ parton fragmentation. We generalize the formalism of parton energy loss to the case of flow-induced oriented momentum transfer. We also discuss how to embed this calculation in hydrodynamic simulations. Flow effects are found to result generically in characteristic asymmetries in the $\eta \times \varphi$ plane of jet-energy distributions and of multiplicity distributions associated with high-$p_T$ trigger particles. However, collective flow also contributes to the medium-induced suppression of single inclusive high-$p_T$ hadron spectra. In particular, we find that low-$p_T$ elliptic flow can induce a sizable additional contribution to the high-$p_T$ azimuthal asymmetry by selective elimination of those hard partons that propagate with significant inclination against the flow field. This reduces, at least partially, the recently observed problem that models of parton energy loss tend to underpredict the large azimuthal asymmetry $v_2$ of high-$p_T$ hadronic spectra in semiperipheral Au + Au collisions.

The cumulant method is applied to study elliptic flow ($v_2$) in Au+Au collisions at $\sqrt{s}=200A$ GeV, with the UrQMD model. In this approach, the true event plane is known and both the nonflow effects and event-by-event spatial ($\epsilon$) and $v_2$ fluctuations exist. Qualitatively, the hierarchy of $v_2$s from two-, four-, and six-particle cumulants is consistent with the STAR data; however, the magnitude of $v_2$ in the UrQMD model is only 60% of the data. We find that the four- and six-particle cumulants are good measures of the real elliptic flow over a wide range of centralities except for the most central and very peripheral events. There the cumulant method is affected by the $v_2$ fluctuations. In midcentral collisions, the four- and six-particle cumulants are shown to give a good estimation of the true differential $v_2$, especially at large transverse momentum, where the two-particle cumulant method is heavily affected by the nonflow effects.

The Nijmegen soft-core model for the pseudoscalar meson-baryon interaction is derived, analogous to the Nijmegen NN and YN models. The interaction Hamiltonians are defined and the resulting amplitudes for one-meson exchange and one-baryon exchange in momentum space are given for the general mass case. The partial wave projection is carried through and explicit expressions for the momentum space partial wave meson-baryon potentials are presented.

The $\pi N$ potential includes the t-channel exchanges of the scalar mesons σ and $f_0$, vector meson ρ, tensor mesons $f_2$ and $f_2^{\text{'}}$, and the Pomeron as well as the s- and u-channel exchanges of the nucleon N and the resonances Δ, Roper, and $S_{11}$. These baryonic resonances are not generated dynamically. We consider them, at least partially, as genuine three-quark states, and we treat them in the same way as the nucleon. The Roper and $S_{11}$ resonances were needed to find the proper behavior of the phase shifts at higher energies in the corresponding partial waves. The soft-core $\pi N$ model gives an excellent fit to the empirical $\pi N$ S- and P-wave phase shifts up to $T_{\mathrm{lab}}=600$ MeV. Also, the scattering lengths have been reproduced well, and the soft-pion theorems for low-energy $\pi N$ scattering are satisfied. The soft-core model for the $K^{+}N$ interaction is an SU${}_f(3)$ extension of the soft-core $\pi N$ model. The $K^{+}N$ potential includes the t-channel exchanges of the scalar mesons $a_0,\sigma$, and $f_0$, vector mesons $\rho ,\omega$, and ϕ, tensor mesons $a_2,f_2$, and $f_2^{\text{'}}$, and the Pomeron as well as u-channel exchanges of the hyperons $\Lambda ,\Sigma ,\Sigma (1385)$, and $\Lambda (1405)$. The fit to the empirical $K^{+}N$ S-, P-, and D-wave phase shifts up to $T_{\mathrm{lab}}=600$ MeV is reasonable and certainly reflects the present state of the art. Since the various $K^{+}N$ phase shift analyses are also not very consistent, scattering observables are also compared with the soft-core $K^{+}N$ model. A good agreement for the total and differential cross sections as well as the polarizations is found.

The properties of nuclear matter are discussed with the relativistic mean-field (RMF) theory. Then, we use two models in studying the in-medium properties of ${\Theta }^{+}$: A pointlike ${\Theta }^{+}$ in the usual RMF and a $K\pi N$ structure for the pentaquark. It is found that the in-medium properties of ${\Theta }^{+}$ are dramatically modified by its internal structure. The effective mass of ${\Theta }^{+}$ in medium is, at normal nuclear density, about 1030 MeV in the pointlike model, whereas it is about 1120 MeV in the $K\pi N$ pentaquark model. The nuclear potential depth of ${\Theta }^{+}$ in the $K\pi N$ model is approximately −37.5 MeV, much shallower than −90 MeV in the usual pointlike RMF model.

The ${}^{32}\mathrm{Cl}$(p,γ)${}^{33}\mathrm{Ar}$ reaction rate is of potential importance in the rp process powering type I x-ray bursts. Recently, Clement et al. [Phys. Rev. Lett. 92, 172502 (2004)] [1] presented new data on excitation energies for low-lying proton unbound states in ${}^{33}\mathrm{Ar}$ obtained with a new method developed at the National Superconducting Cyclotron Laboratory. We use their data, together with a direct capture model and a shell model calculation, to derive a new reaction rate for use in astrophysical model calculations. In particular, we take into account capture on the first excited state in ${}^{32}\mathrm{Cl}$, and we also present a realistic estimate of the remaining uncertainties. We find that the ${}^{32}\mathrm{Cl}$($p,\gamma$)${}^{33}\mathrm{Ar}$ reaction rate is dominated entirely by capture on the first excited state in ${}^{32}\mathrm{Cl}$ over the whole temperature range relevant in x-ray bursts. In the temperature range from 0.2 to 1 GK the rate is up to a factor of 70 larger than the previously recommended rate based on shell model calculations only. The uncertainty is now reduced from up to a factor of 1000 to a factor of 3 at 0.3–0.7 GK and a factor of 6 at 1.5 GK.