Pi(0) electroproduction of the Delta(1232) resonance at high momentum transferred.

摘要

The N → Delta transition has played a major role for many years in understanding the structure of the nucleon. The electromagnetic quadrupole to dipole ratios REM = E1+/M1+ and RSM = S1+/M 1+ of the transition are considered key observables in the study of the dynamics of baryons.; The object of this analysis is the study of unpolarized pi0 electroproduction of the Delta(1232) resonance at high Q2 produced in Hall B at Jefferson Laboratory. The electron beam had an energy of 5.75 GeV and impunged on a cryogenic Hydrogen target. The experiment was performed between September 2001 and January 2002.; The CLAS spectrometer was used to detect the scattered electron and final state proton, and the pi0 was reconstructed by the missing mass technique.; The pi0 angular distributions were obtained over the full c.m. angles coverage for a Q2 range 2 to 6 GeV2/c2. The quantities M 1+, G*M , REM and RSM have been extracted assuming M1+ dominance and other prescriptions.; We find that REM crosses zero between Q2 of 3.5 and 4.0 GeV2, R SM is about -10% and G*M falls faster than the magnetic dipole GD.