Can one measure timelike Compton scattering at LHC ?

Understand

Exclusive photoproduction of dileptons, gamma N->e+e-N, is and will be measured in ultraperipheral collisions at hadron colliders, such as the Tevatron, RHIC and the LHC .

• We demonstrate that the timelike deeply virtual Compton scattering (TCS) mechanism gamma q -> e+e- q where the lepton pair comes from the subprocess gamma q -> gamma* q dominates in some accessible kinematical regions, thus opening a new way to study generalized parton distributions (GPD) in the nucleon.
• High energy kinematics enables to probe parton distributions at small skewedness.
• This subprocess interferes at the amplitude level with the pure QED subprocess gamma gamma* -> e+e- where the virtual photon is radiated from the nucleon.