Electroproduction of Phi(1020) Mesons at High Q^2 with CLAS

by Santoro, Joseph Peter

Abstract (Summary)
This analysis studies the reaction ep? e'p'? in the kinematical range 1.6 < Q² < 5.0 GeV² and 2.0 < W < 3.0 GeV² at CLAS. After successful signal identification, total and differential cross sections are measured and compared to the world data set. Comparisons are made to the predictions of the Jean-Marc Laget(JML) model based on Pomeron plus 2-gluon exchange. The overall scaling of the total cross section was determined to be 1/Q^(4.6±1.7) which is compatible within errors to the Vector Meson Dominance prediction of 1/Q^4 as well as to the expected behavior of a quark and gluon exchange-dominated model described by Generalized Parton Distributions of 1/Q^6. The differential cross section d?/d? was used to determine that the s-channel helicity conservation (SCHC) assumption is valid within the precision of the current data. SCHC leads to a simple expression for the decay angular distribution from which R, the ratio of the longitudinal to the transverse cross section, can be extracted. Under the assumption of SCHC, we determine R=1.33 ±0.18 at an average Q² of 2.21 GeV² which leads to a determination of the longitudinal cross section ?L=5.3±1.3 nb for exclusive ? production.
Bibliographical Information:

Advisor:Tetsuro Mizutani; Mark Pitt; John Ficenec; Elton Smith; Uwe Tauber

School:Virginia Polytechnic Institute and State University

School Location:USA - Virginia

Source Type:Master's Thesis



Date of Publication:08/27/2004

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