Separated Response Function Ratios in Forward Pion Electroproduction
- 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 (TJNAF), 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
- Resource Relation:
- Conference: 2007 Annual Meeting of the Division of Nuclear Physics, Newport News, Virginia, October 10–13, 2007
- Country of Publication:
- United States
- Language:
- English
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