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delta. (1236)-isobar degrees of freedom and the strength of spin-isospin resonances

Conference · · AIP Conf. Proc.; (United States)
OSTI ID:5559710

The most interesting feature of the spin-isospin modes excited in charge-exchange reactions is the magnitude of the transition strength. In the case of the Gamow-Teller resonances (GTR) there exists a well established, model-independent sum rule which is simply connected with the number of protons and neutrons: S/sub ..beta../sup -//-S/sub ..beta../sup +// = 3(N-Z), where the 1.h.s. is the difference between the ..beta../sup -/ and ..beta../sup +/ GT-strength. So far only about 60% of this sum rule strength has been detected experimentally. Conventional nuclear structure effects seem to be unable to explain the missing GT-strength. Several years ago already ..delta..-isobar degrees of freedom were suggested to play an important role in the quenching of the axial-vector coupling constant gA/sup 2/. In this contribution the author presents a consistent calculation of different experimental quantities in the /sup 48/Ca-region which are all connected with the spin-isospin part of the particle-hole interaction. This part of the force is of crucial importance in connection with the quenching. 9 references, 4 figures.

Research Organization:
Institut fuer Kernphysik, Juelich, West Germany
OSTI ID:
5559710
Report Number(s):
CONF-821050-
Journal Information:
AIP Conf. Proc.; (United States), Journal Name: AIP Conf. Proc.; (United States) Vol. 57; ISSN APCPC
Country of Publication:
United States
Language:
English