Deeply virtual Compton scattering and hard exclusive pion production measured by HERMES Original Research Article

Sizeable beam helicity and charge asymmetries arising from the Deeply Virtual Compton Scattering (DVCS) process in the hard electro-production of real photons have been measured for the first time by HERMES. A large asymmetry using an unpolarised beam and a longitudinal polarised target has been observed in the exclusive electro-production of π+. Measurement of these reactions provides access to the presently unknown Generalised Parton Distributions (GPD) of the nucleon.