The exclusive channel p(e,e(')p)pi(0) was studied in the first and second nucleon resonance regions in the Q(2) range from 0.187 to 0.770 GeV(2) at Jefferson Lab using the CEBAF Large Acceptance Spectrometer. Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the pi(0) and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set, once included in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A(1/2) and S(1/2) for the Roper resonance N(1400)P(11) and the N(1535)S(11) and N(1520)D(13) states.
First measurement of target and double spin asymmetries for polarized-e polarized-p ---> e p pi0 in the nucleon resonance region above the Delta(1232)
RICCO, GIOVANNI;TAIUTI, MAURO GINO;
2008-01-01
Abstract
The exclusive channel p(e,e(')p)pi(0) was studied in the first and second nucleon resonance regions in the Q(2) range from 0.187 to 0.770 GeV(2) at Jefferson Lab using the CEBAF Large Acceptance Spectrometer. Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the pi(0) and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set, once included in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A(1/2) and S(1/2) for the Roper resonance N(1400)P(11) and the N(1535)S(11) and N(1520)D(13) states.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.