A comprehensive formalism is developed to preserve the gauge invariance of currents describing the photo- or electroproduction of mesons off the nucleon when the final-state interactions of mesons and nucleons is taken into account explicitly. Replacing exchange currents by auxiliary currents, it is found that all contributions due to explicit final-state interactions are purely transverse and do not contain a Kroll-Ruderman–type contact current. The relation of the present formulation to tree-level-type prescriptions is shown.

Based upon the analogy to the electroweak phase diagram, I propose that in QCD there might be a critical line for a superfluid transition, in the plane of chemical potential and temperature. The order parameter has the quantum numbers of the H dibaryon, but the transition is driven by color superconductivity in strange quark matter.

Coherent and incoherent ${\mu }^{-}\to e^{-}$ conversion channels in ${}^{27}\mathrm{Al}$ and ${}^{48}\mathrm{Ti}$ targets are investigated in detail. We present the results for the transition matrix elements of the conversion operators constructed in the conventional extensions of the standard model as well as supersymmetric theories. The nucleus ${}^{27}\mathrm{Al}$ has recently been employed as a target in a new ${\mu }^{-}\to e^{-}$ conversion experiment (MECO) at Brookhaven with the aim to search for physics beyond the standard model at a relative sensitivity ${10}^{-17}.$ Based on our calculated transition matrix elements, this experiment will lead to very severe constraints for the flavor violation parameters. For ${}^{48}\mathrm{Ti},$ which is currently used as a target in the new run of the SINDRUM II experiment at PSI, we use the most recent experimental data to extract new limits for the lepton flavor nonconservation. We have also evaluated separately the isoscalar and isovector contributions to the ${\mu }^{-}\to e^{-}$ conversion.

The absorption of flux for fusion from a coupled channels system has been examined over a wide range of energies. The full absorption matrix for fusion, consisting of the diagonal absorption and the fusion in transition, is presented. The fusion in transition is at times more than the removal of flux while propagating in the physical channels. The absorption matrix is obtained also for the case of purely real coupling potentials. The absorption matrix method is shown to be superior to the usual method of difference of cross sections used in some of the present coupled channels fusion codes. The flux absorbed within a given channel has been resolved into the constituent subchannels of the total angular momentum. Using this approach, the isocentrifugal approximation has been examined for various cases.

Bloch et al. [Phys. Rev. C 60, 062201 (1999)] presented a calculation of the electromagnetic form factors of the nucleon using an ansatz for the quark-diquark solution of the relativistic three-quark Faddeev equation. In this Comment it is pointed out that the calculation of these form factors stems from a three-quark bound state current that contains overcounted contributions. The corrected expression for the three-quark bound state current is derived.

The microscopic role of nuclear magnetism in rotating frame is investigated for the first time in the framework of the cranked relativistic mean field theory. It is shown that nuclear magnetism modifies the expectation values of single-particle spin, orbital, and total angular momenta along the rotational axis effectively creating additional angular momentum. This effect leads to the increase of kinematic and dynamic moments of inertia at given rotational frequency and has an impact on effective alignments.

We analyze the two-nucleon system below the pion threshold, using a chiral quark cluster model. We solve multichannel resonating group method equations in momentum space, treating them as a set of Lippmann-Schwinger equations. Deuteron data and scattering phase shifts up to a total angular momentum $J=6\mathrm{}$ are presented. Full couplings to $N\Delta$ and $\Delta \Delta$ channels are considered and analyzed. High angular momentum partial waves $\mathrm{}(L>\mathrm{}2\mathrm{})\mathrm{}$ provide a detailed test of chiral symmetry in the two-nucleon system. D waves still show important short-range effects. Low angular momentum partial waves and deuteron observables are in good agreement with the experimental data, showing that the underlying quark structure provides the required short-range potential behavior.

Results for recoil nucleon induced polarization for ${(e,e}^{\prime }\overrightarrow{p})$ are presented using various approximations for the relativistic nucleonic current, at the kinematics of a recent experiment at Bates. We see that the dynamical relativistic effects improve the agreement with the data. We make predictions for the induced normal polarization and responses for TJNAF 89-033 and Mainz A1/2-93 experiments.

Targets of ${}^{48}\mathrm{Ca}$ have been bombarded with ${}^{134,136}\mathrm{Xe}$ beams as part of a search for long-lived, high-K states in well-deformed nuclei with $A\approx 180.$ Several known isomers were observed by off-line γ-ray detection, and limits have been established for high-K isomer production in various isotopes of hafnium $(A=175\mathrm{}–178),$ tantalum $(A=177\mathrm{}–181),$ and tungsten $(A=177\mathrm{}–181).$

We present an algorithm for Monte-Carlo selection of exciton energies for reactions induced by clusters. Reaction mechanisms are addressed that involve a dissolution of the cluster into its constituent nucleons followed by the initiation of a preequilibrium cascade. Calculated single differential spectra and excitation functions for ${}^{93}\mathrm{Nb}(\alpha ,xn)$ reactions are compared with experimental results to illustrate use of this method. Some advantages of exclusive computational techniques over analytic inclusive methods are summarized.

Using the generating functional method, the $\sigma$ and $\omega$ meson propagators in nuclear matter have been determined in relativistic nonlinear models. The scalar and vector collective modes as well as the density dependence of the $\omega$ meson mass have been considered.

Weak interaction rates for very short-lived neutron-rich nuclides involved in the r process are mostly beyond the experimental reach at the present time. Accurate theoretical predictions demand a coherent extrapolation of different nuclear properties away from the experimentally known regions. The β-decay and neutrino-capture rates are estimated within the extended Thomas-Fermi plus Strutinsky integral method and the continuum quasiparticle random phase approximation. This approximation on the self-consistent calculation of the ground-state and β-decay properties is described. The large-scale calculations of the β-strength function for stable and short-lived nuclei are performed to estimate, simultaneously, the β-decay and electron neutrino capture rates for nuclides of relevance to the r-process nucleosynthesis. A comparison of the results with existing experimental data, global calculations, and self-consistent microscopic predictions is presented.

A study of multiparticle correlations on the basis of the maximum fluctuation of the charged particle density in narrow pseudorapidity intervals in Monte Carlo background particles has been carried out with ${}^{16}\mathrm{O}-\mathrm{A}\mathrm{g}\mathrm{B}\mathrm{r}$ interactions at $60A\mathrm{GeV}$ and ${}^{32}\mathrm{S}-\mathrm{A}\mathrm{g}\mathrm{B}\mathrm{r}$ interactions at $200A\mathrm{GeV}.$ The study reveals the existence of dynamical multipion correlation in the pseudorapidity interval 0.1–1 for both data sets. Further study suggests that in each case the maximum charged particle density in a given pseudorapidity interval increases linearly with charged particle multiplicity.

Using the bubble chamber technique, double-pion production cross sections induced by deuteron-proton collisions were measured in the deuteron incident momentum range of 2.1 to $3.8\hspace{0.5em}\mathrm{GeV}/c.\mathrm{}$ The nucleon-nucleon double-pion production cross sections were also deduced from the data. The $\mathrm{dp}$ double-pion production data were interpreted as the sum of nucleon-nucleon double-pion production reactions involving only one of the nucleons in the deuteron, and two sequential nucleon-nucleon single-pion production reactions involving both nucleons in the deuteron. Good fits to the data were obtained, if the nucleon-nucleon double-pion production is assumed to go through intermediate states involving $N\left(1440\right)\mathrm{}$ and $\Delta \mathrm{}\left(1232\right),$ and each nucleon-nucleon single-pion production is assumed to go through the intermediate $N\Delta \mathrm{}\left(1232\right)\mathrm{}$ state.

A measurement of the ${}^{12}\mathrm{C}{+}^{16}\mathrm{O}$ breakup of ${}^{28}\mathrm{Si}$ following ${}^{24}\mathrm{Mg}$ scattering from targets of carbon, lithium oxide, and beryllium has been performed. A study of the relative energy of the correlated ${}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O}$ fragments has allowed the excitation energy of states in ${}^{28}\mathrm{Si}$ to be determined. A comparison of the excitation energy spectra in ${}^{28}\mathrm{Si}$ obtained from the three targets indicates that the same states are populated in the ${}^{12}\mathrm{C}{(}^{24}\mathrm{Mg}{,}^{12}{\mathrm{C}}^{16}\mathrm{O}{)}^8\mathrm{Be},$ ${}^7\mathrm{Li}{(}^{24}\mathrm{Mg}{,}^{12}{\mathrm{C}}^{16}\mathrm{O})t,$ and ${}^9\mathrm{Be}{(}^{24}\mathrm{Mg}{,}^{12}{\mathrm{C}}^{16}\mathrm{O}{)}^5\mathrm{He}$ reactions. The data support the hypothesis that the reaction mechanism populating the ${}^{12}\mathrm{C}{+}^{16}\mathrm{O}$ breakup states observed in these channels is $\alpha$ transfer, and rule out an alternative involving resonant, or “doorway,” states in the ${}^{12}\mathrm{C}{+}^{24}\mathrm{Mg}$ compound system.

Precise experimental g factors of the first $2^{+}$ states of ${}^{50}\mathrm{Ti},$ ${}^{52}\mathrm{Cr},$ and ${}^{54}\mathrm{Fe}$ have been measured. They differ markedly from the g factors of the ${\mathrm{}(7/2)\mathrm{}}^{-}$ ground states of the odd-mass neighbors. The experimental results show that the g factors, ${g(2\mathrm{}}_1^{+})$ and $g\left({\mathrm{}(7/2)\mathrm{}}^{-}\right),$ lie approximately on straight lines as a function of Z albeit with different slopes. Shell model calculations were performed in which up to t nucleons were excited from the $f_{7/2}$ shell. The data are reproduced by calculations using the FPD6 interaction with $t=1.\mathrm{}$ However, the slope flattens out in the calculations with higher t. The sign of a key matrix element which allows for $f_{5/2}$ admixture is positive for the FPD6, zero for the KB3, and negative for the FPY interactions, respectively, indicating that a better understanding of the effective interaction in this region is needed.

We study implications of a model which links nuclear and nucleon structure functions. For this model, computed Callen-Gross functions ${\kappa }^A{(x,Q}^2{)=2\mathrm{xF}}_1^A{(x,Q}^2{)/F}_2^A{(x,Q}^2)$ are for finite $Q^2$ close to their asymptotic value 1. Using those $\kappa ,$ we compute R ratios for $Q^2\gtrsim 5{\mathrm{GeV}}^2.$ We review approximate methods for the extraction of R from inclusive scattering and EMC data. We also calculate ratios of moments of $F_k^A$ and find these to describe the data and in particular their $Q^2$ dependence. The above observables, as well as inclusive cross sections, are sensitive tests for the underlying relation between nucleonic and nuclear structure functions. In view of the overall agreement, we speculate that the above relation effectively circumvents a QCD calculation.

We present results from Brueckner-Hartree-Fock calculations for $\beta$-stable neutron star matter with nucleonic and hyperonic degrees of freedom, employing the most recent parametrizations of the baryon-baryon interaction of the Nijmegen group. It is found that the only strange baryons emerging in $\beta$-stable matter up to total baryonic densities of 1.2 ${\mathrm{fm}}^{-3}$ are ${\Sigma }^{-}$ and $\Lambda .$ The corresponding equations of state are then used to compute properties of neutron stars such as masses and radii.

We calculate the density dependence of the $\rho$-meson mass and coupling constant ${(g}_{\rho \mathrm{NN}})$ for $\rho$-nucleon-nucleon vertex at one loop using the Lagrangian where the $\rho$ meson is included as a dynamical gauge boson of a hidden local symmetry. We found that the $\rho$-meson mass and the coupling constant for $g_{\rho \mathrm{NN}}$ drop as density increases in the low energy limit.