Speaker
Description
Measurements of exclusive meson production are a useful tool in the study of
hadronic structure. In particular, one can discern the relevant degrees of
freedom at different scales through these studies. In the transition region
between low momentum transfer (where description of hadronic degrees of freedom
in terms of effective hadronic Lagrangians is valid) and high momentum transfer
(where degrees of freedom are quarks and gluons), $t$-channel exchange of a few
Regge trajectories permits an efficient description of the energy dependence
and the forward angular distribution of many real- and virtual-photon-induced
reactions. In this work, we study the $p(e,e'\pi^+)n$ reaction at fixed $Q^2$
and $W$ of 2.5 GeV$^2$ and 2.0 GeV, respectively, while varying the four
momentum transfer to the nucleon $-t$ from 0.2 to 2.1 GeV$2$. As $-t$ is
increased, the hadronic interaction scale is reduced independently of the
observation scale of the virtual photon, providing valuable information about
the hard-scattering process in general. The data was taken at Jefferson Lab
Hall C in 2004 using the HMS and SOS magnetic spectrometers, and I will present
the preliminary result of the differential cross section analysis in this talk.
(*) Supported by NSERC SAPIN-2016-00031
