A relativistic study of the nucleon helicity amplitudes
M. De Sanctis1 - E. Santopinto2 - M.M. Giannini2
1 INFN, Sezione di Roma, P.le A.Moro 2, I-00185 Roma, Italy
2 Dipartimento di Fisica dell'Università di Genova, I.N.F.N., Sezione di Genova, via Dodecaneso
33, 16164 Genova, Italy (e-mail:giannini@genova.infn.it)
Received: 16 April 1998 Communicated by V.V. Anisovich
Abstract
We perform a calculation of the relativistic transition form factors for the
electromagnetic excitation of the nucleon resonances. We use as input the 3-quark wave functions
obtained in a Constituent Quark Model with three-body forces in the hypercentral
approach. With respect to the non relativistic calculations a significant contribution is
obtained up to 
. However, the low Q2-behaviour exhibits a lack of
strength, which may be connected with the need of taking into account explicitly further degrees
of freedom beyond the three constituent quark ones.
PACS
12.39.Ki Relativistic quark model -
13.40.Gp Electromagnetic form factors -
14.20.Gk Baryon resonances with S = 0
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