The effective SU(2) chiral Lagrangian with external sources is given in the presence of nonvanishing nucleon densities by calculating the in-medium contributions of the chiral pion-nucleon Lagrangian. As a by-product, a relativistic quantum field theory for Fermi many-particle systems at zero temperature is directly derived from relativistic quantum field theory with functional methods.

The singlet and triplet differential cross sections for $p\overrightarrow{p}\mathrm{pp}{\pi }^0$ have been estimated for the first time at 325, 350, 375, and 400 MeV using the results of the recent experimental measurements [Phys. Rev. C 63, 064002 (2001)] of Meyer et al.

The centrality dependence of thermal parameters, characterizing the hadron multiplicities, is determined phenomenologically for lead-on-lead collisions at CERN-SPS for a beam energy of 158A GeV. The strangeness equilibration factor shows a clear, approximately linear, increase with increasing centrality, while the freeze-out temperature and chemical potential remain constant.

We present a new analysis of the E772 and E866 experiments on the nuclear dependence of Drell-Yan (DY) lepton pair production resulting from the bombardment of ${}^2\mathrm{H},$ Be, C, Ca, Fe, and W targets by $800\hspace{0.5em}\mathrm{GeV}/c$ protons at Fermilab. We employ a light-cone formulation of the DY reaction in the rest frame of the nucleus, where the dimuons detected at small values of Bjorken $x_2\ll 1$ may be considered to originate from the decay of a heavy photon radiated from an incident quark in a bremsstrahlung process. We infer the energy loss of the quark by examining the suppression of the nuclear-dependent DY ratios seen as a function of projectile momentum fraction $x_1$ and dimuon mass M. Shadowing, which also leads to nuclear suppression of dimuons, is calculated within the same approach employing the results of phenomenological fits to deep inelastic scattering data from HERA. The analysis yields $-dE/dz=2.73\mathrm{}\pm 0.37\pm 0.5\hspace{0.5em}\mathrm{G}\mathrm{e}\mathrm{V}/\mathrm{f}\mathrm{m}$ for the rate of quark energy loss per unit path length, a value consistent with theoretical expectations including the effects of the inelastic interaction of the incident proton at the surface of the nucleus. This is the first observation of a nonzero energy loss effect in such experiments.

This paper reports a precision measurement of the ratio of the exclusive capture rates from the two hyperfine levels of the muonic ${}^{11}\mathrm{B}$ atom leading to the excited level of ${}^{11}\mathrm{Be}$ at 320 keV: ${\lambda }^{+}/{\lambda }^{-}=0.028\mathrm{}\pm 0.021(\mathrm{stat}.\mathrm{})\pm 0.003$ (syst.). Using the most up-to-date halo wave functions of the nuclei involved, the induced pseudoscalar to axialvector form factor ratio is obtained as $g_P{/g}_A{=4.3\mathrm{}}_{-4.3}^{+2.8\mathrm{}}(\mathrm{stat}.\mathrm{})\pm 0.5$ (syst.). This value agrees with the partial conservation of the axial current prediction and does not reproduce the anomaly observed in radiative muon capture on hydrogen. The hyperfine conversion rate between the two hyperfine levels is also determined, $R=[181\pm 16(\mathrm{stat}.\mathrm{})\pm 1(\mathrm{syst}.\mathrm{}\left)\right]\times {10}^3\hspace{0.5em}{\mathrm{s}}^{-1}.$ The total capture rate from the lower hyperfine level and its difference compared to the upper one were also determined: ${\lambda }_C^{-}=[23.53\pm 0.72(\mathrm{stat}.\mathrm{})\pm 0.25(\mathrm{syst}.\mathrm{}\left)\right]\times {10}^3\hspace{0.5em}{\mathrm{s}}^{-1}$ and $\Delta \lambda =[-13.2\pm 1.7(\mathrm{stat}.\mathrm{})\pm 0.7(\mathrm{syst}.\mathrm{}\left)\right]\times {10}^3\hspace{0.5em}{\mathrm{s}}^{-1}.$

We calculate in this work the rates for the neutrino pair production by nucleon-nucleon bremsstrahlung taking into account the full contribution from a nuclear one-pion-exchange potential. It is shown that if the temperatures are low enough $(T<~20\hspace{0.5em}\mathrm{MeV}),$ the integration over the nuclear part can be done for the general case, ranging from the completely degenerate (D) to the nondegenerate (ND) regime. We find that the inclusion of the full nuclear contribution enhances the neutrino pair production by $\mathrm{nn}$ and $\mathrm{pp}$ bremsstrahlung by a factor of about 2 in both the D and ND limits when compared with previous calculations. This result may be relevant for the physical conditions of interest in the semitransparent regions near the neutrinosphere in type II supernovae, cooling of neutron stars, and other astrophysical situations.

The g factors of $2_1^{+},$ $4_1^{+},$ and $2_2^{+}$ states in the stable ${}^{130,132,134,136}\mathrm{Xe}$ isotopes have been measured via projectile Coulomb excitation in inverse kinematics in combination with the transient field technique. The results show a steady decrease in ${g(2\mathrm{}}_1^{+})$ as the number of neutron holes increases in the lighter nuclei below the closed $N=82\mathrm{}$ neutron shell. The g factors of the $4_1^{+}$ states in ${}^{132,134}\mathrm{Xe}$ are consistently larger than the g factors of the $2_1^{+}$ states, a characteristic of proton excitation. The g factors of the $2_1^{+},$ $4_1^{+},$ and $2_2^{+}$ states in ${}^{130}\mathrm{Xe}$ are approximately equal as would be expected for vibrational excitations.

Even-even $A\approx 110$ nuclei approaching the astrophysical r-process path have been investigated using both the cranked and the configuration-constrained shell models. The calculations show that, with increasing neutron number in the $Z>~40$ nuclides, nuclear shapes evolve from prolate, through triaxial to oblate deformations. In contrast to other regions of the nuclear chart, pronounced oblate shapes dominate the collective rotation from ground states to very high spins $\left(I\sim 40\right),$ when $N>~70.$ The stability of the oblate shapes is due to the simultaneous upper-shell neutron and proton Fermi surfaces, reinforced by the rotation alignment behavior of both nucleon types. Configuration-constrained calculations predict the coexistence of well-deformed prolate and oblate multiquasiparticle (isomeric) states.

Nuclei in the vicinity of the doubly-magic ${}^{100}\mathrm{Sn}$ nucleus have been studied, and an extended level scheme for ${}^{102}\mathrm{In}$ has been established. The level structure comprises both the negative parity states involving the $\nu h_{11/2}$ orbital, and levels due to the breakup of the doubly-magic ${}^{100}\mathrm{Sn}$ core. Results of a large-scale shell model calculation, using realistic and empirical effective interactions with ${}^{88}\mathrm{Sr}$ as a core, are in very good agreement with the experimental data.

We have obtained information on the atomic hyperfine splitting and, hence, on magnetic moments in neutron-rich ${}^{68,70}\mathrm{Cu}$ isotopes by scanning the frequency of the narrow-band laser of the first excitation step in the resonance ionization laser ion source. The deduced magnetic moments are $\mu {(}^{68}{\mathrm{Cu}}^g{,I}^{\pi }{=1\mathrm{}}^{+})=+2.48\mathrm{}(2\left)\mathrm{}\right(7)\mathrm{}{\mu }_N,$ $\mu {(}^{68}{\mathrm{Cu}}^m{,I}^{\pi }{=6\mathrm{}}^{-})=+1.24\mathrm{}(4\left)\mathrm{}\right(6)\mathrm{}{\mu }_N,$ and $\mu {(}^{70}{\mathrm{Cu}}^{m_2}{,I}^{\pi }{=1\mathrm{}}^{+})=+1.86\mathrm{}(4\left)\mathrm{}\right(6)\mathrm{}{\mu }_N,$ $\mu {[}^{70}{\mathrm{Cu}}^g{,I}^{\pi }{=(6\mathrm{}}^{-}\left)\right]=(+)1.50\left(7\right)\mathrm{}\left(8\right)\mathrm{}{\mu }_N.$ The results of the scans analysis points out the existence of a new isomer, ${}^{70}{\mathrm{Cu}}^{m_1}.$ Its deduced magnetic moment is $\left(-\right)3.50\mathrm{}\left(7\right)\mathrm{}\left(11\right)\mathrm{}{\mu }_N,$ in good agreement with the $I^{\pi }{=3\mathrm{}}^{-}$ assignment. The method of in-source atomic spectroscopy, as well as the analysis of the obtained data, is described. The results are discussed in terms of single-particle configurations coupled to the ${}^{68}\mathrm{Ni}$ core.

We have measured neutron resonances in the palladium isotopes 104, 105, and 110 for neutron energies from 1 to 2100 eV. Many new p-wave resonances have been observed. Their neutron widths and, in several cases, the radiative widths were measured. The average level spacings and the s-wave and p-wave neutron strength functions were determined. The time-of-flight method was used for both neutron total cross section measurements and total $(n,\gamma )$ reaction yield measurements at the pulsed spallation neutron source of Los Alamos Neutron Science Center. Well established resonance spectroscopy for these isotopes is essential for the analysis of parity violation data that were recently measured in palladium.

Recently we outlined an analytical method of solving the time-dependent Schrödinger equation for a model which simulates a decaying quantum system such as an $\alpha$-decaying nucleus. A particle in the model is initially confined around the origin and leaks out, tunneling through a potential barrier. The solution can be expressed as a linear combination of the Moshinsky functions, each of which is associated with a pole of the scattering $\mathbf{S}$ matrix of the model. In this paper we give a full account of the method with a few explicit examples. We examine deviations from the exponential decay law at very large times. We comment on a recent controversy regarding the t dependence of the survival and nonescape probabilities when t is very large.

We have studied $\alpha {-}^{12}\mathrm{C}$ angular correlations for peaks observed in the ${}^{12}\mathrm{C}{[}^{12}\mathrm{C}{,}^{12}\mathrm{C}{(3\mathrm{}}_1^{-}\left){]}^{12}\mathrm{C}{(0\mathrm{}}_1^{+}\right)$ inelastic-scattering excitation function in the energy range between $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=25\mathrm{}$ to 35 MeV. The excitation-function data for $\alpha$-particle angles that correspond to the population of specific magnetic substates in the excited, decaying ${}^{12}\mathrm{C}$ nucleus suggest that these peaks are associated with a preferentially aligned configuration. The angular-correlation data are consistent with spin assignments of $J^{\pi }{=16\mathrm{}}^{+}$ and ${18}^{+}$ for the resonancelike structures observed at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=27.5\mathrm{}\hspace{0.5em}\mathrm{MeV}$ and 33.1 MeV, respectively. The observed alignment, and the deduced spin values are consistent with a dinuclear configuration for these peaks.

Reaction cross section ${\sigma }_R$ of proton-rich isotones $\mathrm{}(N=10\mathrm{})\mathrm{}$ near ${}^{23}\mathrm{Al}$ and Al isotopes ${(}^{23-28}\mathrm{Al})$ on C target have been measured at intermediate energies around 30 MeV/nucleon. An abnormal increase of the experimental ${\sigma }_R$ is observed for ${}^{23}\mathrm{Al}$ and it suggests that there is an anomalously large matter rms radius in ${}^{23}\mathrm{Al}.$ Together with the very weakly binding of the last proton ${(S}_p=0.125\mathrm{}\hspace{0.5em}\mathrm{MeV}),$ it indicates that there is a proton halo in ${}^{23}\mathrm{Al}.$ This conclusion is also supported by the difference factor d which is deduced from the measured and theoretical ${\sigma }_R$ in the Glauber or Boltzmann-Uehling-Uhlenbeck model and is used for the manifest of halo phenomena. The theoretical calculation based on the relativistic density dependent Hartree model shows that there is a proton halo when the last proton is in the ${2s}_{1/2}$ orbit in ${}^{23}\mathrm{Al}.$ The significance of the proton halo in ${}^{23}\mathrm{Al}$ is discussed.

We present continuum random phase approximation (CRPA) calculations for charged-current neutrino-nucleus scattering. The CRPA formalism is based on a Green’s-function approach, and the calculations can be done in a self-consistent fashion when using an effective nucleon-nucleon force of the Skyrme type. We analyze the technical aspects related to the description of charge-exchange reactions within this approach, and study the sensitivity of the results to the single-particle characteristics of the formalism. Muon capture is studied as a test case. In applications of the formalism, we concentrate on neutrino-scattering off ${}^{12}\mathrm{C}$ and ${}^{16}\mathrm{O},$ and pay attention to interactions of experimental interest.

An extended study of scaling of the first and second kinds for inclusive electron scattering from nuclei is presented. Emphasis is placed on the transverse response in the kinematic region lying above the quasielastic peak. In particular, for the region in which electroproduction of resonances is expected to be important, approximate scaling of the second kind is observed and the modest breaking of it is shown probably to be due to the role played by an inelastic version of the usual scaling variable.

The isoscalar toroidal dipole strength distributions in spherical nuclei are calculated in the framework of a fully consistent relativistic random phase approximation. It is suggested that the recently observed “low-lying component of the isoscalar dipole mode” might correspond to the toroidal giant dipole resonance. Although predicted by several theoretical models, the existence of toroidal resonances has not yet been confirmed in experiment. The strong mixing between the toroidal resonance and the dipole compression mode might help to explain the large discrepancy between theory and experiment on the position of isoscalar giant dipole resonances.

Magnetic dipole transitions in the self-conjugate nucleus ${}^{32}\mathrm{S}$ up to an excitation energy of 12 MeV have been investigated in inelastic electron scattering at ${\Theta }_e=180\mathrm{}°$ at the superconducting Darmstadt electron linear accelerator (S-DALINAC). Transition strengths have been determined from a plane-wave Born approximation analysis including Coulomb distortion. For the two strongest $M1\mathrm{}$ transitions, where a discrepancy of a factor of about 2 was observed in previous ${(e,e}^{\prime })$ experiments, values intermediate between the two extremes are deduced from the present work. The resulting strength distribution is well described by shell-model calculations using the unified $\mathrm{sd}$-shell interaction and an effective $M1\mathrm{}$ operator. The shell-model wave functions also provide a reasonable description of the form factors. A quasiparticle random phase approximation calculation is less successful. The present results allow for the first time studies of the form factor of extremely weak l-forbidden and isoscalar $M1\mathrm{}$ excitations in ${}^{32}\mathrm{S}.$ The l-forbidden transition allows a sensitive test of tensor corrections to the $M1\mathrm{}$ operator. A combined analysis with the isospin-analog Gamow-Teller (GT) transitions in the $A=32\mathrm{}$ triplet reveals a situation similar to previous studies in $A=39\mathrm{}$ nuclei: microscopic calculations reasonably account for the GT strengths, but fail in the case of $M1\mathrm{}$ strengths. A possible explanation may be found in the nonrelativistic treatment of the latter. Some examples of the role of relativistic corrections are discussed. A consistent description of the reduced transition strength and the form factor of the isoscalar $M1\mathrm{}$ excitation requires isospin mixing with the close-lying isovector transitions. The extracted Coulomb matrix elements are roughly within the limits set by the approximate constancy of the spreading width derived from the analysis of compound-nucleus reactions.

A many-body Hamiltonian comprising pairing, quadrupole-quadrupole and spin-spin interactions is treated within a projected spherical basis with the aim of describing the detailed structure of the magnetic states of orbital and spin-flip nature in ${}^{144,148-154}\mathrm{Sm}.$ The mean field for the single-particle motion takes care of the volume conservation of a phenomenological core, which results in having a complex dependence on deformation for single-particle energies. Several experimental features like the total orbital and total spin strengths, the shape of the orbital strength distribution, the hump structure of the spin strength distribution, the quadratic dependence of the orbital strength on nuclear deformation, and the saturation effect of the orbital strength with respect to the Casten factor P are very well described within a quasiparticle random-phase approximation formalism. A comparison of the present results with those obtained in some previous treatments is also given.

Results are presented from nuclear resonance fluorescence experiments on the odd-mass nuclei ${}^{121}\mathrm{Sb}$ and ${}^{123}\mathrm{Sb}$ with $Z=51.\mathrm{}$ The improved sensitivity reached with the present NRF facility, installed at the 4.3 MV Dynamitron accelerator of the Stuttgart University, allowed the detection of huge numbers of weak photoexcitations in the stable Sb nuclei ${}^{121}\mathrm{Sb}$ (164 transitions) and ${}^{123}\mathrm{Sb}$ (83 transitions) in the energy range up to 4 MeV and 3.5 MeV, respectively. The data are compared to former results for odd-mass nuclei near the $Z=50\mathrm{}$ and $N=82\mathrm{}$ shell closures ${(}^{117}\mathrm{Sn},$ ${}^{139}\mathrm{La},$ ${}^{141}\mathrm{Pr},$ and ${}^{143}\mathrm{Nd}).\mathrm{}$ In the odd-mass nuclei within the $Z=50\mathrm{}$ region, a similar total amount of electromagnetic excitation strength below 4 MeV is found; however, in ${}^{121}\mathrm{Sb}$ and ${}^{123}\mathrm{Sb}\hspace{0.5em}\mathrm{}(Z=51\mathrm{})\mathrm{}$ this strength is much more fragmented than in ${}^{117}\mathrm{Sn}$ with a closed proton shell $\mathrm{}(Z=50\mathrm{}).$