Electroproduction of {delta}(1232) resonance at high momentum transfer

Journal Article · Fri May 29 04:00:00 EDT 1998 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.56090· OSTI ID:21199124

Frolov, V ^[1]

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1. Physics Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

Jefferson Lab experiment E94-014 measured the the excitation of the {delta}(1232) resonance at Q{sup 2} near 2.8 and 4 Gev{sup 2}/c{sup 2} via the reaction p(e,e{sup '}p){pi}{sup 0}. This is the highest Q{sup 2} for which exclusive resonance electroproduction has ever been observed. Decay distributions of the {delta}(1232) resonance into the p{pi}{sup 0} final state were measured over a wide range of barycentric decay angles and energies. The goal of this experiment is to asses the transition in Q{sup 2} from the constituent quark model (CQM) to the regime where hard processes become important. At Q{sup 2}{approx}few GeV{sup 2}/c{sup 2} the ratio E{sub 1+}/M{sub 1+} depends dramatically on the theoretical description, varying from a few 10{sup -2} in the CQM limit, to about 1 in the pQCD limit. Preliminary analysis of the data shows that the ratio E{sub 1+}/M{sub 1+} remains small at Q{sup 2} up to 4 Gev{sup 2}/c{sup 2}. After first pass analysis we obtain E{sub 1+}/M{sub 1+}=-4.1{+-}1.2% at Q{sup 2}=2.8 Gev{sup 2}/c{sup 2} and E{sub 1+}/M{sub 1+}=-7.9{+-}0.8% at Q{sup 2}=4 Gev{sup 2}/c{sup 2} (statistical errors only)

• OSTI ID: 21199124
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 432; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CEBAF ACCELERATOR
DELTA-1232 BARYONS
E1-TRANSITIONS
ELECTRON-PROTON INTERACTIONS
ELECTRONS
ELECTROPRODUCTION
ERRORS
EXCITATION
FOUR MOMENTUM TRANSFER
M1-TRANSITIONS
PARTICLE DECAY
PIONS NEUTRAL
PROTONS
QUARK MODEL