Charge-exchange isobaric resonances

Yu.S Lutostansky,N Arsenyev,T Shneidman,I Rogov,A Bezbakh,A Vdovin

doi:10.1051/epjconf/201819402009

Abstract

Three types of the charge-exchange isobaric resonances - giant Gamow-Teller (GTR), the analog (AR) and pygmy (PR) ones are investigated using the microscopic theory of finite Fermi systems and its approximated version. The calculated energies of GTR, AR and three PR’s are in good agreement with the experimental data. Calculated differences ΔEG-A=EGTR-EAR go to zero in heavier nuclei indicating the restoration of Wigner SU(4)-symmetry. The average deviation for ΔEG-A is 0.30 MeV for the 33 considered nuclei where experimental data are available. The comparison of calculations with experimental data on the energies of charge-exchange pygmy resonances gives the standard deviation δE<0:40 MeV. Strength functions for the 118Sn, 71Ga, 98Mo and 127I isotopes are calculated and the calculated resonance energies and amplitudes of the resonance peaks are close to the experimental values. Strong influence of the charge-exchange resonances on neutrino capturing cross sections is demonstrated.

Highlights

Charge-exchange isobaric states are manifested in the corresponding charge-exchange reactions such as (ν, e), (p, n), (n, p), (3He, t), (t,3 He), (6Li,6 He) and others, or in β-transitions in nuclei
The theoretical studies of these collective states have began with the first calculations of the giant Gamow–Teller resonance (GTR) [1] and other collective states [2] long before their experimental studies in charge-exchange reactions [3, 4]
Charge-exchange excitations of nuclei are described in the microscopic theory of finite Fermi systems (TFFS) by the system of equations for the effective field [7]

Summary

Introduction

Charge-exchange isobaric states are manifested in the corresponding charge-exchange reactions such as (ν, e), (p, n), (n, p), (3He, t), (t,3 He), (6Li, He) and others, or in β-transitions in nuclei Among these states, collective resonance excitations are of the most interest. The theoretical studies of these collective states have began with the first calculations of the giant Gamow–Teller resonance (GTR) [1] and other collective states [2] long before their experimental studies in charge-exchange reactions [3, 4]. These collective states lying below the giant GTR [5] were called “pygmy” resonances (PR). The influence of the charge-exchange resonances on neutrino capturing cross sections was investigated

Methods

Results

Conclusion