Timelike Compton Scattering TCS

1
Timelike Compton Scattering (TCS)
TCS collaboration T. Horn, Y. Illieva, F.J.
Klein, P. Nadel-Turonski, S. Stepanyan
E1-6
6 GeV untagged photon beam
GPD model predictions
R
E. Berger et al., hep-ph/0110062
7000 events above f peak
Q25 GeV2 E?13 GeV

• To leading order and at infinite Q2, TCS and DVCS
  amplitudes are equivalent. At finite Q2, they are
  complementary and can provide a better
  understanding of the reaction mechanism.
• The asymmetry, R, constructed from the angular
  distribution of the lepton pair is a sensitive
  test of GPD models.
• The CLAS-g12 experiment, the first where TCS can
  be studied using a tagged photon beam, can form
  the basis of a 12-GeV program.