Dispersive optical potential from an analysis of neutron single-particle energies in the Ti, Cr, and Fe isotopes featuri

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CLEI Experiment

Dispersive Optical Potential from an Analysis of Neutron Single-Particle Energies in the Ti, Cr, and Fe Isotopes Featuring 20 to 50 Neutrons O. V. Bespalova* , T. A. Ermakova, A. A. Klimochkina, E. A. Romanovsky, and T. I. Spasskaya Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow, 119991 Russia Received January 16, 2012

Abstract—Neutron single-particle energies in unstable Ti, Cr, and Fe isotopes containing 20 to 26 neutrons were evaluated on the basis of experimental proton energies in the mirror-symmetric nuclei. The neutron single-particle energies in the 20  N  50 Ti, Cr, and Fe isotopes were calculated on the basis of the mean-field model with a dispersive optical potential, and the results were compared with available experimental data and with the results of estimations and calculations based on the relativistic mean-field model and on the multiparticle shell model with the GXPF1 interaction. DOI: 10.1134/S106377881211004X

1. INTRODUCTION The dispersive optical model (DOM) [1] was developed for the example of describing single-particle properties of spherically symmetric doubly magic and magic nuclei 40 Са, 90 Zr, and 208 Pb. For these nuclei, there is experimental information both about scattering cross sections σ(θ), polarizations P (θ), and total reaction cross sections σr for a large number of projectile energies Ek and about the single-particle expt energies Enlj (where n is the principal quantum number, while l and j are, respectively, the orbital angular and total angular momenta). An analysis of σ(θ), P (θ), and σr for various values of Ek on the basis of DOM for the nuclei in question made it possible to develop methods for determining the parameters of the Hartree–Fock and dispersive components [VHF (r, E) and ΔV (r, E), respectively] of the dispersive optical potential (DOP) for positive energies (E > 0) and a method for extrapolating these energy dependences to the region of negative energies DOM for these (E < 0). This permitted evaluating Enlj expt

nuclei and comparing the resulting values with Enlj . expt

DOM and E The attained agreement between Enlj nlj gave impetus to performing a large number of studies devoted to a further development of DOM. A method for constructing DOPs for describing single-particle properties of spherical nuclei, including unstable ones, for which experimental information about σ(θ), P (θ), and σr is incomplete or is absent was proposed and developed in the studies of our *

E-mail: [email protected]

group (see [2, 3] and references therein). The method is based on employing regularities in nucleon– nucleus scattering that were reflected in modern systematics of global parameters of the potential of the traditional (nondispersive) optical model and in the expt new most precise information on Enlj from a global evaluation of data for nucleon-stripping and nucleonpickup reactions on the same nucleus [4]. The dependences of the DOP parameters on the number of neutrons in an isotope are established within the expt proposed method