Response Function Ratios

Fri., Oct. 31, 2014 2:15 p.m. - Fri., Oct. 31, 2014 3:15 p.m.

Location: CL 345

Title: Separated Response Function Ratios in Exclusive, Forward π-/π+ Electroproduction

Abstract: The study of exclusive π± electro-production on the nucleon, including separation of the structure functions, is a very useful tool in the study of hadronic structure. In contrast to inclusive (e,e') or photo-production measurements, the transverse momentum (size) of the scattering constituent and the resolution at which it is probed can be varied independently. Furthermore, ratios of separated response functions can be formed for which non-perturbative corrections may partially cancel, yielding insight into soft-hard factorization at modest Q2. Our results are intriguing, as the ratio of transverse cross sections RT=σπ-T/σπ+T suggests a transition between pion-knockout and quark-knockout mechanisms as the Mandelstam variable -t is increased. The ratio of longitudinal cross sections RL=σπ-L/σπ+L is also of interest as it confirms the dominance of the pion-pole diagram at low -t, which is necessary for the extraction of the charged pion form factor from electro-production data.

Speaker: Prof. Garth M. Huber, Department of Physics, University of Regina