[Deeppwg] Abstract for CIPANP

[Stepan Stepanyan]

Dear Deep working group friends,

We were asked by convenors of "Nucleon Structure" session at CIPANP2012
to present our Time-like Compton Scattering studies with CLAS. We do not
have a speaker yet, but we still have been encouraged to submit an abstract.
Abstract is below. Please send comments to me as soon as possible.

Thanks, Stepan
=====================
A broad program for studying the quark and gluon structure of hadrons, 
and in particular,
probing nucleon structure using deeply virtual exclusive reactions and 
the formalism of
Generalized Parton Distributions (GPDs) is underway at Jefferson Lab. 
Deeply Virtual Compton
Scattering (DVCS), $ep\to ep\gamma, has been the focus of interest as it 
provides the cleanest
tool for accessing the quark GPDs of the nucleon. Time-like DVCS, also 
known as Time-like
Compton Scattering (TCS), is the inverse process to space-like DVCS that 
can be probed through
the photoproduction of lepton pairs ($l^+l^-$). TCS can be an eective 
tool for studying the real
part of the Compton amplitude. Combining space-like and time-like data 
thus oers additional
constraints on the GPDs.

Studies of lepton pair production are started at Jeerson Lab using 6 
GeV CLAS data. In this report,
preliminary results on angular asymmetries in TCS and extraction of the 
real part of Compton
form-factors using CLAS electroproduction data will be presented. We 
will also discuss future plans
for di-lepton production in 12-GeV era using the CLAS12 detector and an 
11 GeV electron beam.
The CEBAF 12 GeV upgrade will allow us to study TCS in the range of 
outgoing photon virtualities
($Q^2$) from 4 GeV$^2$2 to 9 GeV$^2$ (above the light-quark meson 
resonances and below charm
threshold) and access the nucleon's gluonic structure at large x through 
$J/Psi$ photoproduction.