Results 1 - 10 of 3865
Results 1 - 10 of 3865. Search took: 0.026 seconds
|Sort by: date | relevance|
[en] The 22+ state in 132Te is identified as the one-phonon mixed-symmetry state in a projectile Coulomb excitation experiment presenting a firm example of a mixed-symmetry state in unstable, neutron-rich nuclei. The results of shell-model calculations based on the low-momentum interaction Vlow-k are in good agreement with experiment demonstrating the ability of the effective shell-model interaction to produce states of mixed-symmetry character.
[en] A relationship between experimental E2 matrix elements and nuclear quadrupole charge deformation and triaxiality is presented. Examples of experimentally determined deformation and triaxiality parameters in various regions of the nuclear chart are specified. The most interesting results were found among transitional nuclei. The first such result from a radioactive beam facility is the identification of a triaxial strongly-deformed low-lying 02+ level in 76Kr. (author)
[en] The basic characteristics and features of the coherent excitation of particles moving through a crystal-a new physical phenomenon predicted and experimentally discovered at ITEP-are discussed
[en] A recent Coulomb excitation study has called into question the 4+ spin assignment of the 1414-keV level in 232Th, which had earlier been interpreted as a two-phonon γ-vibrational excitation, and had suggested instead a 3- assignment. Data obtained in the present neutron scattering study of 232Th are inconsistent with the 3- suggestion and support an Iπ=4+ assignment for the 1414-keV level, lending credence to the argument that it is a Kπ=4+ band head
[en] This lecture will be limited to the field of very heavy nuclei, like actinides and uranides, because of special interest is Coulomb excitation in this region where the collective bands cannot be reached by (HI,xnγ) reactions, where a predominant competition comes from fission. (author)
[en] We present the first measurement of photoproduction of J/ψ and of two-photon production of high-mass e+e- pairs in electromagnetic (or ultra-peripheral) nucleus-nucleus interactions, using Au + Au data at √sNN = 200 GeV. The events are tagged with forward neutrons emitted following Coulomb excitation of one or both Au* nuclei. The event sample consists of 28 events with me+e+ > 2 GeV/c2 with zero like-sign background. The measured cross sections at midrapidity of dσ/dy (J/ψ + Xn,y = 0) = 76 ± 33(stat) ± 11(syst) μb and d2σ/dm dy(e+e- + Xn, y = 0) = 86 ± 23(stat) ± 16(syst) μb/(GeV/c2) for me+e- (elementof) (2.0,2.8) GeV/c2 have been compared and found to be consistent with models for photoproduction of J/ψ and QED based calculations of two-photon production of e+e- pairs.
[en] The yrast spectroscopy at high-spin in nuclei has been extensively developed for the last ten years, both experimentally and theoretically. Progress has been achieved in the understanding of the nuclear structure at high-spin, especially in terms of quasiparticle motion in rotating potentials. There are at present two ways of populating nuclear high-spin states, namely Coulomb excitations and (HI,xn) reactions. By means of Coulomb excitations one can reach, for the moment, states with spin I≤32. Thus, the quantitative information on the yrast spectroscopy of high-spin states comes from the analysis of discrete γ-rays emitted from evaporation residues in (HI,xn) reactions. The highest spin (the highest rotational frequency) obtained in this kind of analysis is at present I≤45. This is certainly the region of spin at which one expects a drastic change of pair-correlations as well as the deviation of the nuclear shape from axial-symmetry
[en] We have extracted the B(E1) strength for the transition 1/2+→ 1/2- occurring in 11Be from the recent Coulomb excitation measurements using the nonrelativistic and intermediate-energy Coulomb-excitation (IECE) theory and have found that the results of IECE theory are in good agreement with the adopted value of B(E1). When the survival probability of the projectile is taken into account the agreement between the calculated and the adopted value of B(E1) strength improves further. We have also studied the effect of diffuseness parameter of survival probability on the B(E1) strength.