We analyze amplitudes for the pion electroproduction on proton derived from Lagrangians based on the local chiral $\mathrm{SU}\mathrm{}\left(2\right)\mathrm{}\times \mathrm{SU}\mathrm{}\left(2\right)\mathrm{}$ symmetries. We show that such amplitudes do contain information on the nucleon weak axial form factor $F_A$ in both soft and hard pion regimes. This result invalidates Haberzettl’s recent claim that the pion electroproduction at threshold cannot be used to extract any information regarding $F_A.$

In-beam cross section measurements of the ${}^{93}\mathrm{Nb}(p,\gamma {)}^{94}\mathrm{Mo}$ reaction have been carried out at $E_p=1.4\mathrm{}–4.9\mathrm{MeV},$ by using high efficiency high-purity Ge detectors, partly with BGO shields for Compton background suppression. From the resulting cross sections, which lie in the 0.5–300 μb range, astrophysical S factors as well as reaction rates have been obtained. By means of the statistical compound nucleus theory of Hauser and Feshbach, cross sections and reactions rates have also been calculated. A good agreement between the experimental data and the theoretical predictions has been found.

We calculate in heavy baryon chiral perturbation theory the local $\mathrm{NN}$ potentials generated by the two-pion exchange diagrams at two-loop order. We give explicit expressions for the mass spectra (or imaginary parts) of the corresponding isoscalar and isovector central, spin-spin and tensor $\mathrm{NN}$ amplitudes. We find from two-loop two-pion exchange, a sizable isoscalar central repulsion that amounts to 62.3 MeV at $r=1.0\mathrm{}\mathrm{fm}.$ There is a similarly strong isovector central attraction that, however, originates mainly from the third-order low-energy constants $d_j$ entering the chiral $\pi N$-scattering amplitude. We also evaluate the one-loop $2\pi$-exchange diagram with two second-order chiral $2\pi \mathrm{NN}$ vertices proportional to the low-energy constants $c_{1,2,3,4}$ as well as the first relativistic $1/M$ correction to the $2\pi$-exchange diagrams with one such vertex. The diagrammatic results presented here are relevant components of the chiral $\mathrm{NN}$ potential at next-to-next-to-next-to-leading order.

We have performed a Faddeev calculation of the baryon spectrum for the chiral constituent quark model including higher orbital angular momentum states. We have found that the effect of these states is important, although a description of the baryon spectrum of the same quality as that of the one given by including only the lowest-order configurations can be obtained. We have studied the effect of the pseudoscalar quark-quark interaction on the relative position of the positive- and negative-parity excitations of the nucleon as well as the effect of varying the strength of the color-magnetic interaction.

Within nuclear thermodynamics and an isospin-dependent transport model we investigate respective roles of the nuclear mean field and the two-body stochastic scattering on the evolution of density and isospin fluctuations in either mechanically or chemically unstable regions of neutron-rich matter. It is found that the mean field dominates overwhelmingly the fast growth of both fluctuations, while the two-body scattering influences significantly the later growth of the isospin fluctuation only. Moreover, both fluctuations grow in mechanically unstable systems, while only the density fluctuation grows significantly in chemically unstable ones. Furthermore, the magnitude of both fluctuations decreases with the increasing isospin asymmetry because of the larger reduction of the attractive isoscalar mean field by the stronger repulsive neutron symmetry potential in the more neutron-rich matter. Finally, several experimental measurements are proposed to test these findings.

The photoproduction of $K^{*}$ vector mesons is investigated in a quark model with an effective Lagrangian. Including both baryon resonance excitations and t-channel exchanges, observables for the reactions $\gamma \overrightarrow{p}{K}^{*0}{\Sigma }^{+}$ and $\gamma \overrightarrow{p}{K}^{*+}{\Sigma }^0$ are predicted, using the SU(3)-flavor-blind assumption of nonperturbative QCD.

The ${}^{33}\mathrm{Na}$ β decay was studied online using mass separation techniques and a first description of the level structure of the neutron-rich isotope ${}^{33}\mathrm{Mg},$ with $N=21,$ has been obtained. The experiment involved the measurement of β-γ, β-γ-γ, and $\beta -n-\gamma$ coincidences as well as neutron spectra by time-of-flight technique. The first low energy level scheme for the daughter nucleus ${}^{33}\mathrm{Mg}$ is given with five bound states. Spin and parity assignments are proposed according to β feedings and γ-ray multipolarities. β-strength distribution is evaluated, taking into account $1n$- and $2n$-emission channels and it is compared with the calculated GT strength distribution. In particular, the $1p-1h$ and $2p-2h$ excitations are shown to result in substantial contribution to the low energy configurations. Allowed β branch to the ${}^{33}\mathrm{Mg}$ g.s. $[\log ft=5.27\mathrm{}(26\left)\mathrm{}\right]$ gives direct evidence for the inversion of $\nu {(f}_{7/2})$ and $\nu {(d}_{3/2})$ states.

Excited states have been populated in ${}^{108}\mathrm{In}$ and ${}^{110}\mathrm{In}$ in complementary backed- and thin-target experiments using the Stony Brook and the $8\pi \mathrm{Ge}$-detector arrays. The level schemes for both isotopes have been extended and modified, including the first observation of $\Delta I=2\mathrm{}$ bands in ${}^{110}\mathrm{In}.$ Lifetimes of states in four $\Delta I=1\mathrm{}$ bands and one $\Delta I=2\mathrm{}$ band have been measured using the Doppler-shift attenuation method. Experimental total angular momenta and reduced transition strengths for the $\Delta I=1\mathrm{}$ bands have been compared with tilted axis cranking predictions for shears bands with configurations involving one proton $g_{9/2}$ hole and one or three valence quasineutrons from the $h_{11/2}$ and $g_{7/2}{/d}_{5/2}$ orbitals. The $\Delta I=2\mathrm{}$ bands have been compared with principal axis cranking predictions for configurations with two $g_{9/2}$ proton holes and a $g_{7/2}$ or $d_{5/2}$ proton and one- or three-quasineutron configurations involving the $h_{11/2}$ and $g_{7/2}{/d}_{5/2}$ orbitals. In general, there is good overall agreement for both the angular momenta and reduced transition strengths. The $\Delta I=1\mathrm{}$ and $\Delta I=2\mathrm{}$ bands have large ${\mathcal{J}}^{\mathrm{}\left(2\right)\mathrm{}}/B\left(E2\mathrm{}\right)\mathrm{}$ ratios as expected for the shears mechanism. The $B\left(M1\mathrm{}\right)\mathrm{}$ strengths deduced for the $\Delta I=1\mathrm{}$ bands show a decreasing trend as a function of spin, which is also a feature of the shears mechanism. Configuration assignments have been made for most observed bands based on comparisons with theory and systematics of neighboring nuclei.

The structure of near neutron midshell ${}^{116}\mathrm{Cd}$ has been investigated via β decay of ${}^{116}{\mathrm{Ag}}^m$ by β-γ and γ-γ coincidence spectroscopy. The ${}^{116}{\mathrm{Ag}}^m$ activity was produced by symmetric fission of natural uranium induced by 25 MeV protons. The ion guide technique has been employed to produce online mass separated sources. The decay scheme of ${}^{116}{\mathrm{Ag}}^m$ has been considerably extended by adding 19 new excited states of ${}^{116}\mathrm{Cd}.$ The newly identified ${}^{116}\mathrm{Cd}$ state at 1869.7 keV, along with other four levels near 2 MeV, are interpreted as forming the complete three-phonon quintuplet. The vibrational structure of ${}^{116}\mathrm{Cd}$ is discussed in the context of an anharmonic vibrator.

Semianalytical expressions are suggested for the temperature dependence of those combinations of transport coefficients that govern the fission process. This is based on experience with numerical calculations within the linear response approach and the locally harmonic approximation. A reduced version of the latter is seen to comply with Kramers’s simplified picture of fission. It is argued that for variable inertia his formula has to be generalized, as already required by the need that for overdamped motion the inertia must not appear at all. This situation may already occur above $T\approx 2\hspace{0.5em}\mathrm{MeV},$ where the rate is determined by the Smoluchowski equation. Consequently, comparison with experimental results does not give information on the effective damping rate, as often claimed, but on a special combination of local stiffnesses and the friction coefficient calculated at the barrier.

We analyze the predictions of perturbative QCD for pion photoproduction on the deuteron $\gamma \overrightarrow{D}{\pi }^{0}D$ at large momentum transfer using the reduced amplitude formalism. The cluster decomposition of the deuteron wave function at small binding only allows the nuclear coherent process to proceed if each nucleon absorbs an equal fraction of the overall momentum transfer. Furthermore, each nucleon must scatter while remaining close to its mass shell. Thus the nuclear photoproduction amplitude ${\mathcal{M}}_{\gamma \overrightarrow{D}{\pi }^{0}D}\mathrm{}(u,t)\mathrm{}$ factorizes as a product of three factors: (1) the nucleon photoproduction amplitude ${\mathcal{M}}_{\gamma N_1\to {\pi }^0{N}_1}\mathrm{}(u/4,t/4\mathrm{})\mathrm{}$ at half of the overall momentum transfer, (2) a nucleon form factor $F_{N_2}\mathrm{}(t/4\mathrm{})\mathrm{}$ at half the overall momentum transfer, and (3) the reduced deuteron form factor $f_d\mathrm{}\left(t\right),$ which, according to perturbative QCD, has the same monopole falloff as a meson form factor. A comparison with the recent JLAB data for $\gamma \overrightarrow{D}{\pi }^{0}D$ of Meekins et al. [Phys. Rev. C 60, 052201 (1999)] and the available $\gamma \overrightarrow{p}{\pi }^{0}p$ shows good agreement between the perturbative QCD prediction and experiment over a large range of momentum transfers and center-of-mass angles. The reduced amplitude prediction is consistent with the constituent counting rule $p_T^{11}{\mathcal{M}}_{\gamma \overrightarrow{D}{\pi }^{0}D}\to F\left({\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}\right)$ at large momentum transfer. This is found to be consistent with measurements for photon lab energies $E_{\mathrm{lab}}>3\mathrm{}$ GeV at ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=90\mathrm{}°$ and $E_{\mathrm{lab}}>10\mathrm{}$ GeV at $136°.$

We present measurements of the differential and total cross sections and the $\Lambda$ polarization for the reaction $K^{-}\overrightarrow{p}\eta \Lambda$ from threshold to $p_{K^{-}}=770\mathrm{}\mathrm{MeV}/c,$ with much better precision than previous measurements. Our cross-section data show a remarkable similarity to the $\mathrm{SU}\mathrm{}\left(3\right)\mathrm{}$ flavor-related ${\pi }^{-}\overrightarrow{p}\eta n$ cross-section results. The reaction $K^{-}\overrightarrow{p}\eta \Lambda$ at threshold is dominated by formation of the intermediate $\Lambda \mathrm{}\left(1670\right)\mathrm{}{\frac{1}{2}}^{-}$ state.

This paper investigates interference effects involving the $E1\mathrm{}$ and $E2\mathrm{}$ multipole contributions to the ${}^{12}\mathrm{C}(\alpha ,{\gamma }_0{)}^{16}\mathrm{O}$ reaction. The relationships between $\gamma$-ray angular distributions, $E1\mathrm{}$ and $E2\mathrm{}$ capture phases, and ${}^{12}\mathrm{C}+\alpha$ elastic scattering phase shifts are clarified. A detailed study of the energy- and angle-dependent effects near the 2.68-MeV resonance is presented, where a new experimental signature has been identified. In addition, the effects of center-of-mass motion and $\gamma$-ray polarization are discussed.

We have measured the electromagnetic matrix element ${B(E2;0\mathrm{}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}\to 2_1^{+})$ in the radioactive nucleus ${}^{26}\mathrm{Si}$ using the method of intermediate energy Coulomb excitation. Our result, ${B(E2;0\mathrm{}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{+}\to 2_1^{+})=336\mathrm{}(33)\mathrm{}{e}^2{\mathrm{fm}}^4,$ resolves a conflict in previous measurements of this matrix element. In addition, the present measurement allows us to determine $M_n{/M}_p$ for ${}^{26}\mathrm{Mg}$ using the mirror nucleus method. The mirror method result of $M_n{/M}_p=1.05\mathrm{}\left(6\right)\mathrm{}$ is consistent with the most recent pion scattering results and is near the simple collective model expectation.

Pairing correlations for excited nuclei near the proton drip line are described by using finite-temperature BCS equations including the continuum part of the spectrum. The suitability of the proposed method to obtain stable solutions in the presence of single-particle resonances is shown.

In the Thomas-Fermi model, calculations are presented for nuclei beyond the nuclear drip line at zero temperature. These nuclei are in equilibrium by the presence of an external gas, as may be envisaged in the astrophysical scenario. We find that there is a limiting asymmetry beyond which these nuclei can no longer be made stable.

Intermediate mass fragments $(3\mathrm{}<~Z<~25)$ in correlation with projectilelike and targetlike fragments have been revealed among the ternary events produced in 11.6 MeV/nucleon ${}^{209}\mathrm{Bi}{+}^{208}\mathrm{Pb}$ reaction. Their characteristics (energy and angular distributions) are in agreement with the emission from the neck zone formed between projectile and target during partially damped collision. The analysis indicates that they can be produced by various mechanisms. Till now fragments with similar behavior were observed at incident energies above 20 MeV/nucleon.

Several nucleon-nucleon potentials, Paris, Nijmegen, Argonne, and those derived by quantum inversion, which describe the $\mathrm{NN}$ interaction for $T_{\mathrm{Lab}}<~300\hspace{0.5em}\mathrm{MeV},$ are extended in their range of application as $\mathrm{NN}$ optical models. Extensions are made in r space using complex separable potentials definable with a wide range of form factor options including those of boundary condition models. We use the latest phase shift analysis SP00 (FA00, WI00) of Arndt et al. from 300 MeV up to 3 GeV to determine these extensions. The imaginary parts of the optical model interactions account for loss of flux into direct or resonant production processes. The optical potential approach is of particular value as it permits one to visualize fusion, and subsequent fission, of nucleons when $T_{\mathrm{Lab}}>2\mathrm{}\hspace{0.5em}\mathrm{}\mathrm{GeV}.$ We do so by calculating the scattering wave functions to specify the energy and radial dependences of flux losses and of probability distributions. Furthermore, half off the energy shell t matrices are presented as they are readily deduced with this approach. Such t matrices are required for studies of few- and many-body nuclear reactions.

The lifetimes of low-lying states in the superdeformed (SD) bands of ${}^{194}\mathrm{Hg}$ were measured by means of the recoil distance method using Gammasphere and the Cologne plunger device. The deduced transitional quadrupole moments in all three bands were found to be constant within the experimental uncertainties and equal those extracted from Doppler-shift attenuation method measurements for the higher-lying states, confirming that the decay out does not strongly affect the structure of the SD bands. The experimental findings are used to discuss the different mechanisms proposed for the decay out of SD bands.

We investigate the pairing property of nuclear matter with the relativistic Hartree-Bogoliubov (RHB) approach. Recently, the RHB approach has been widely applied to nuclear matter and finite nuclei. We have extended the RHB approach to be able to include nonlinear coupling terms of mesons. In this paper we apply it to nuclear matter and observe the effect of nonlinear terms on pairing gaps.