New lifetime limits on the charge nonconserving electron capture with excitation of ${}^{127}\mathrm{I}$ and ${}^{23}\mathrm{Na}$ nuclear levels are established. The statistics used is $34866\hspace{0.5em}\mathrm{kg}\mathrm{day}$; it has been collected deep underground at the Gran Sasso National Laboratory of INFN by the highly radiopure $\simeq 100\hspace{0.5em}\mathrm{kg}$ DAMA NaI(Tl) setup. These new limits are in the range $(1.5\mathrm{}–2.4)\times {10}^{23}\hspace{0.5em}\mathrm{y}$, up to two orders of magnitude higher than the ones previously available. Stringent restrictions on the relative strengths of the charge nonconserving processes are derived: ${\varepsilon }_W^2<9.6\mathrm{}\times {10}^{-26}$ and ${\varepsilon }_{\gamma }^2<1.2\mathrm{}\times {10}^{-40}$ (90% C.L.).

${}^{152}\mathrm{Sm}$ was recently proposed as a possible example of a spherical-deformed transitional nucleus which exhibits a coexistence of both phases at low energies. We analyze the theoretical foundation of this proposition and its experimental evidence.

The nuclear collective response is investigated in the framework of a doorway picture in which the spreading width of the collective motion is described as a coupling to more and more complex configurations. It is shown that this coupling induces fluctuations of the observed strength. In the case of a hierarchy of overlapping decay channels, we observe Ericson fluctuations at different scales. Methods for extracting these scales and the related lifetimes are discussed. Finally, we show that the coupling of different states at one level of complexity to some common decay channels at the next level, may produce interferencelike patterns in the nuclear response. This quantum effect leads to a new type of fluctuations with a typical width related to the level spacing.

Using the generalized optical theorem for charged particles, the total reaction cross section ${\sigma }_R$ and the nuclear scattering amplitude $f_N$ at $0°$ have been determined model independently for the first time in the ${}^6\mathrm{He}{+}^{12}\mathrm{C}$ system. A large fraction of ${\sigma }_R$ is accounted for by $f_N\left(0\mathrm{}°\right)$ — a manifestation of the nuclear forward glory effect. A comparison with the ${}^6\mathrm{Li}{+}^{12}\mathrm{C}$ system supports the prediction that the high break-up probability of ${}^6\mathrm{He}$ reduces the fraction of the total reaction cross section accounted for by the nuclear scattering amplitude at $0°.$

Within the framework of an isospin-dependent quantum molecular dynamics model, the multifragmentation in reactions of ${}^{112}\mathrm{Sn}{+}^{112}\mathrm{Sn}$ and ${}^{124}\mathrm{Sn}{+}^{124}\mathrm{Sn}$ at 40 MeV/nucleon is investigated. The calculated results are in good qualitative agreement with the experimental data which indicated that there were significantly different scalings of the mean number of intermediate mass fragments with the number of neutron and charged particles between the two reaction systems. Meanwhile, it is shown that the preequilibrium emission may affect strongly these scalings.

We investigate the residual effect of $\Lambda p$ strong interactions in $\mathrm{pp}$ correlations with one proton from $\Lambda$ decays. It is found that the residual correlation is about 10% of the $\Lambda p$ correlation strength, and has a broad distribution centered around $q\approx 40\hspace{0.5em}\mathrm{MeV}/c.\mathrm{}$ The residual correlation cannot explain the observed structure on the tail of the recently measured $\mathrm{pp}$ correlation function in central Pb+Pb collisions by NA49 at the Super Proton Synchrotron.

Nonperturbative effective field theory calculations for $\mathrm{NN}$ scattering seem to break down at rather low momenta. By examining several toy models, we clarify how effective field theory expansions can in general be used to properly separate long- and short-range effects. We find that one-pion exchange has a large effect on the scattering phase shift near poles in the amplitude, but otherwise can be treated perturbatively. Analysis of a toy model that reproduces ${}^1{S}_0$ $\mathrm{NN}$ scattering data rather well suggests that failures of effective field theories for momenta above the pion mass can be due to short-range physics rather than the treatment of pion exchange. We discuss the implications this has for extending the applicability of effective field theories.

We have performed shell-model calculations for the $N=126\mathrm{}$ isotones ${}^{210}\mathrm{Po},$ ${}^{211}\mathrm{At},$ and ${}^{212}\mathrm{Rn}$ using a realistic effective interaction derived from the Bonn-A nucleon-nucleon potential by means of a G-matrix folded-diagram method. The calculated binding energies, energy spectra, and electromagnetic properties show remarkably good agreement with the experimental data. The results of this paper complement those of our previous study on neutron hole Pb isotopes, confirming that realistic effective interactions are now able to reproduce with quantitative accuracy the spectroscopic properties of complex nuclei.

The induced momentum spectrum of soft gluons radiated from a high energy quark propagating through a QCD medium is derived in the Baier-Dokshitzer-Mueller-Peigné-Schiff formalism. A calorimetric measurement for the medium-dependent energy lost by a jet with opening angle ${\theta }_{\mathrm{cone}}$ is proposed. The fraction of this energy loss with respect to the integrated one appears to be the relevant observable. It exhibits a universal behavior in terms of the variable ${\theta }_{\mathrm{cone}}^2{L}^3\mathrm{q̂}$ where L is the size of the medium and $\mathrm{q̂}$ the transport coefficient. Phenomenological implications for the differences between cold and hot QCD matter are discussed.

Using the Nambu–Jona-Lasinio (NJL) model, the dynamical chiral-symmetry breaking, the light-mesons spectra, and the properties of the mesons have been investigated on the basis of a conventional Hartree-Fock approach. In order to show the advantage of the resonating (Res) mean-field theory for a fermion system with large quantum fluctuations over the usual mean-field theory, we apply it to the NJL model to describe more precisely such phenomena associated with the pionic excitation. For the sake of simplicity, a state with large quantum fluctuations is approximated by the superposition of two Dirac seas, namely nonorthogonal Slater determinants (S-dets) with different correlation structures. We consider two cases: in the first case both Dirac seas are composed of equal “constituent quark masses” while in the second case the constituent quark masses are unequal. We make a direct optimization of the Res-mean-field energy functional, i.e., a variation of the Res-mean-field ground-state energy with respect to the Res-mean-field parameters, the “constituent quark masses.” Then the Res-mean-field ground and excited states generated with the S-dets explain most of a mass spectrum and associated properties of the pion.

We calculate electromagnetic form factors of the proton bound in specified orbits for several closed-shell nuclei. The shell structure of the finite nuclei, together with the internal quark substructure of the nucleon, are self-consistently described by the quark-meson-coupling model. We find that the medium-modified electric and magnetic form factors of the bound nucleon deviate considerably from those of the free nucleon. Our results suggest that this medium correction on the nucleon’s quark substructure may be detectable in forthcoming quasielastic electron-nucleus scattering.

The cross section for the $p{d}^3\mathrm{He}\hspace{0.5em}{\pi }^{+}{\pi }^{-}$ reaction has been measured in a kinematically complete experiment at a c.m. excess energy of $Q=70\mathrm{}$ MeV. The striking energy and angular distributions are reproduced in a simple model calculation where it is assumed that the reaction is dominated by p-wave ${\pi }^{+}{\pi }^{-}$ pairs. This is in complete contrast to the results of inclusive measurements at somewhat higher beam energies which show a strong s-wave ABC enhancement at low $\pi \pi$ masses.

The $\beta$-delayed proton precursors ${}^{125}\mathrm{Nd}{,}^{128}\mathrm{Pm},$${}^{129}\mathrm{Sm}{,}^{137}\mathrm{Gd}$, and ${}^{139}\mathrm{Dy}$ near the proton drip line were produced by the irradiation of ${}^{92}\mathrm{Mo}{,}^{96}\mathrm{Ru}$, and ${}^{106}\mathrm{Cd}$ with an ${}^{36}\mathrm{Ar}$ beam, and definitely identified for the first time using proton-gamma coincidence in combination with a He-jet tape transport system. Their half-lives were determined to be 0.60(15) s, 1.0(3) s, 0.55(10) s, 2.2(2) s, and 0.6(2) s, respectively. The measured energy spectra of $\beta$-delayed protons and estimated proton branching ratios to the final states in “daughter” nuclei were fitted by a statistical model calculation, and then the spins and parities of ${}^{125}\mathrm{Nd},$${}^{129}\mathrm{Sm},$${}^{137}\mathrm{Gd}$, $\mathrm{and}{}^{139}\mathrm{Dy}$ were preliminarily assigned as ${5/2}^{\pm },{1/2}^{+}(or\hspace{0.5em}{3/2}^{+}),{7/2}^{\pm }$, and ${7/2}^{+}$, respectively. The agreement between the spin-parity assignments and the predicted Nilsson diagrams indirectly indicates that the ground states of ${}^{125}\mathrm{Nd},$${}^{129}\mathrm{Sm},$${}^{137}\mathrm{Gd}$, ${\mathrm{and}}^{139}\mathrm{Dy}$ are highly deformed with ${\beta }_2\sim 0.3$.

Nucleon form factors are calculated on $q^2\in [0,3]{\mathrm{GeV}}^2$ using an ansatz for the nucleon’s Faddeev amplitude motivated by quark-diquark solutions of the relativistic Faddeev equation. Only the scalar diquark is retained, and it and the quark are confined. A good description of the data requires a nonpointlike diquark correlation with an electromagnetic radius of $0.8r_{\pi }.$ The composite, nonpointlike nature of the diquark is crucial. It provides for diquark-breakup terms that are of greater importance than the diquark photon absorption contribution.

We note that off the quark mass shell the operators ${(p}_i{+p}_f{)}_{\mu }{\gamma }_5$ and $i{\sigma }_{\mu \nu }{(p}_i-p_f{)}^{\nu }{\gamma }_5$, both of which reduce to $-\overrightarrow{\sigma }\cdot \overrightarrow{E}$ in the nonrelativistic limit, are no longer identical. In this paper we explore the effects of this difference in the contribution of these quark electric moments to hadronic electric moments.

Excited states in ${}^{234}\mathrm{U}$ have been populated using the incomplete-fusion reaction ${}^{232}\mathrm{Th}{(}^9\mathrm{Be},\alpha 3n)$ at 52 MeV. The emitted $\gamma$ rays were observed using the CAESAR array, while the $\alpha$ particles were detected with an array of 14 plastic scintillator detectors of phoswich type. This reaction can populate ${}^{234}\mathrm{U}$ at higher spin than the conventional ${}^{232}$Th$(\alpha ,$ $2n)$ reaction because the “${}^5\mathrm{He}$” fragment from breakup of the beam can be viewed as initiating a ${}^{232}\mathrm{Th}{(}^5\mathrm{He},3n)$ reaction. Similar reactions could provide a valuable alternative technique for the study of relatively heavy, neutron-rich isotopes. In the present work, states in the ground-state band of ${}^{234}\mathrm{U}$ were observed up to $J^{\pi }{=18\mathrm{}}^{+}$ and previous tentative observations of ${(9\mathrm{}}^{-})$ and ${(11\mathrm{}}^{-})$ states in the octupole band were confirmed. A new state at 1366 keV, which is possibly the $8^{+}$ member of the $\gamma$ band, has also been identified.

We compare the method used by Navrátil et al. [Phys. Rev. C 59, 611 1999)] for separating physical from spurious solutions to the Faddeev equations with a more general alternative method. The suitability of the Faddeev equations versus the Schrödinger equation is discussed as directly relevant in the same context.

An order parameter of a single event is introduced. Its advantage in describing dynamic fluctuations of a single event is demonstrated.

We discuss the implications of partial dynamical SU(3) symmetry (PDS) for the structure of the lowest ${K=0\mathrm{}}^{+}{(K=0\mathrm{}}_2)$ collective excitation in deformed nuclei. We consider an interacting boson model Hamiltonian whose ground and $\gamma$ bands have good SU(3) symmetry, while the ${K=0\mathrm{}}_2$ band is mixed. It is shown that the double-phonon components in the ${K=0\mathrm{}}_2$ wave function arise from SU(3) admixtures which, in turn, can be determined from absolute $E2\mathrm{}$ rates connecting the ${K=0\mathrm{}}_2$ and ground bands. An explicit expression is derived for these admixtures in terms of the ratio of ${K=0\mathrm{}}_2$ and $\gamma$ bandhead energies. The SU(3) PDS predictions are compared with existing data and with broken-SU(3) calculations for ${}^{168}$Er.

An attempt is made to refit two sets of parameters for the Nijmegen soft core YN potential by including selected bound state data as well as the customary scattering data. One parameter set corresponds closely to the original Nijmegen parameters. The second is a more restricted set. It was not possible to obtain the low ${\chi }^2$ values found in fits which omit the bound state restrictions. The primary difficulty is a conflict between the bound state restrictions and the $\Sigma N$ scattering data. As with the original Nijmegen fit, this difficulty can be traced to the $\Sigma N-\Lambda N$ tensor interaction. This difficulty should not adversely affect the utility of the derived potentials in hypernuclear calculations.