Production of a pion in association with a high-Q2 dilepton pair in antiproton-proton annihilation at GSI-FAIR

Lansberg, J. P.; Pire, B.; Szymanowski, L.

Production of a pion in association with a high-Q2 dilepton pair in antiproton-proton annihilation at GSI-FAIR

Authors

Lansberg, J. P.

Pire, B.

Szymanowski, L.

Description

We evaluate the cross section for anti-p p -> l+ l- pi0 in the forward direction and for large lepton pair invariant mass. In this kinematical region, the leading-twist amplitude factorises into a short-distance matrix element, long-distance dominated antiproton Distribution Amplitudes and proton to pion Transition Distribution Amplitudes (TDA). Using a modelling inspired from the chiral limit for these TDAs, we obtain a first estimate of this cross section, thus demonstrating that this process can be measured at GSI-FAIR.
Latex, 5 pages, 3 figures