Excitation of baryonic resonances in stable medium-mass nuclei of Sn

J L Rodríguez-Sánchez ,K Itahashi ,J Atkinson ,T Aumann ,Y Ayyad ,E Casarejos ,Y K Tanaka ,J Benlliure ,A Estradé ,M Caamaño ,H Geißel ,C Scheidenberger ,J E Ramirez Vargas ,H Lenske ,T Saito ,A Procházka ,M Takechi ,D Pérez–Loureiro ,S Beceiro-Novo ,Isaac Vidaña ,H Weick ,C Paradela ,A Kelić-Heil ,K Boretzky ,H Álvarez‐Pol ,P Fernåndez ,D Cortina-Gil ,Yu A Litvinov ,E Haettner ,S Piétri ,J S Winfield

doi:10.1088/1742-6596/1667/1/012036

Abstract

Isobaric charge-exchange reactions induced by beams of 112Sn have been investigated at the GSI facilities using the fragment separator FRS. The high-resolving power of this spectrometer makes it possible to obtain the isobaric charge-exchange cross sections with an accuracy of 3% and to separate quasi-elastic and inelastic contributions in the missing-energy spectra, in which the inelastic component is associated to the in-medium excitation of baryonic resonances such as the Δ resonance. We report on the results obtained for the (p,n) and (n,p) channels excited by using different targets that cover a large range in neutron excess.

Highlights

The study of baryonic resonances in nuclear matter is considered as a natural extension of nuclear physics
Isobaric charge-exchange reactions induced by stable tin isotopes at energies of 1A GeV on different targets have been investigated at GSI using the fragment separator (FRS) spectrometer
Thanks to the high-resolving power of the magnetic spectrometer FRS we can clearly identify in the missing-energy spectra the quasi-elastic and inelastic components corresponding to the nuclear spin-isospin response of nucleon-hole and baryonic resonance excitations, respectively

Summary

Introduction

The study of baryonic resonances in nuclear matter is considered as a natural extension of nuclear physics. For the study of baryonic resonances in nuclear matter, we use isobaric chargeexchange reactions induced by relativistic beams of stable medium-mass projectile nuclei. These reaction channels guarantee that with a large probability the charge-exchange process is mediated by a quasi-free nucleon-nucleon collision [12]. The momentum resolution of this spectrometer was already proved some time ago to be sufficient to clearly identify the quasi-elastic (Gamow-Teller, spin-isospin dipole and quadrupole resonances, etc) and inelastic (baryon excitations) components in the missing-energy spectra of nuclear residues produced in isobaric charge-exchange reactions, which were induced by projectiles of 208Pb [14]. Details about detector calibrations and data corrections can be found in Ref. [15]

49 Plastic scintillator

Results

Conclusions