The contribution of the Delta(1232) isobar to the electromagnetic current of the two-nucleon system and its role in (gamma,NN) processes is investigated. The difference between the genuine Delta-excitation current and that part of the current connected to the deexcitation of a preformed Delta in the target nucleus is stressed. The latter cannot lead to a resonant behaviour of matrix elements for energies in the Delta region. The reaction O-16(gamma, pp)C-14, where the Delta contribution is dominant at intermediate energies, is considered. The large variations found in the cross sections for different treatments stress the need for a proper treatment of the Delta current for a clear understanding of the reaction mechanism of two-nucleon emission processes.
Treatment of the Delta current in electromagnetics two-nucleon knockout reactions
GIUSTI, CARLOTTA;PACATI, FRANCODAVIDE;
1997-01-01
Abstract
The contribution of the Delta(1232) isobar to the electromagnetic current of the two-nucleon system and its role in (gamma,NN) processes is investigated. The difference between the genuine Delta-excitation current and that part of the current connected to the deexcitation of a preformed Delta in the target nucleus is stressed. The latter cannot lead to a resonant behaviour of matrix elements for energies in the Delta region. The reaction O-16(gamma, pp)C-14, where the Delta contribution is dominant at intermediate energies, is considered. The large variations found in the cross sections for different treatments stress the need for a proper treatment of the Delta current for a clear understanding of the reaction mechanism of two-nucleon emission processes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
