Data on-pair production by pions are examined as a function of x and PT for longitudinal photon polarization. Evidence in the form of a sin2* term in the helicity angular distribution is observed for x near 1. This is conclusive evidence that production in this region is not predominantly through on-shell quark annihilation. The result is consistent with a calculation based on quantum chromodynamics.
ASJC Scopus subject areas
- Physics and Astronomy(all)