Separated Response Function Ratios in Forward Pion Electroproduction

Conference · Mon Oct 01 04:00:00 EDT 2007

OSTI ID:1963881

Butuceanu, Cornel ^[1]

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1. University of Regina

The first complete separation of the four unpolarized electromagnetic response functions above the dominant resonances has been made for forward, exclusive pi± electroproduction on the nucleon. Measurements were made above the resonance region at fixed invariant mass W = 1.95 GeV in the Q2 = 0.6 ? 1.6 (GeV/c)2 range. The separated ratio RL = sigma^pi?_L /sigma^pi+_L is sensitive to any small isoscalar contamination to the dominant isovector pion exchange amplitude which is the basis for the determination of the charged pion form factor, Fpi(Q2) from electroproduction data. A favorable value of this ratio may also have implications for constraining polarized GPD?s with ratios of longitudinal observables. At large ?t, a separated ratio RT = sigma^pi?_T /sigma^pi+_T = 1/4 would suggest a transition between pion knockout and quark knockout mechanisms. Preliminary results on the separate ratios RL and RT and their evolution with ?t will be presented and discussed.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1963881
• Report Number(s): JLAB-PHY-07-950; DOE/OR/23177-5897
• Country of Publication: United States
• Language: English