On the role of the Δ(1232) on the transverse nuclear response in the (e, e′) reaction

The transverse nuclear response to an electromagnetic probe which is limited to create (or destroy) a particle-hole (ph) or delta-hole (Δh) pair is analyzed. Correlations of the random phase approximation (RPA) type and self-energy insertions are considered. For RPA correlations we have developed a...

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Autor principal: Bauer, Eduardo
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 1998
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/123096
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Sumario:The transverse nuclear response to an electromagnetic probe which is limited to create (or destroy) a particle-hole (ph) or delta-hole (Δh) pair is analyzed. Correlations of the random phase approximation (RPA) type and self-energy insertions are considered. For RPA correlations we have developed a scheme which includes explicitly the Δ and the exchange terms. Self-energy insertions over ph and Δh bubbles are studied. Several residual interactions based on a contact plus a (π + ϱ)-meson exchange potential are used. All calculations are performed in non-relativistic nuclear matter. The main effect of the Δ is to reduce the intensity over the nuclear quasi-elastic peak. Exchange RPA terms are very important, while the terms with self-energy insertions depend strongly on the residual interaction employed. Our results are compared with data for 40 Ca at momentum transfer q = 410 and q = 550 MeV/c, where the longitudinal response is also briefly discussed.