T. Gehrmann et M. Stratmann, BETHE-HEITLER PROCESS IN POLARIZED PHOTON-NUCLEON INTERACTIONS, Physical review. D. Particles and fields, 56(9), 1997, pp. 5839-5843
We calculate the Bethe-Heitler cross section for the production of lep
ton pairs in the field of a longitudinally polarized nucleon, taking i
nto account the lepton masses and the target mass. This process is a d
ominant background to the detection of open charm from semileptonic de
cay modes, which is a potential probe of the polarized gluon distribut
ion in the nucleon.