[Hybrid RBRC seminar] The x -> xi region in processes involving GPDs

by Jakob Schoenleber (RBRC/BNL)

Thursday 14 Dec 2023, 12:30 → 13:30 US/Eastern

2-160 (https://bnl.zoomgov.com/j/1619458475?pwd=Z1VDdXVXcWF1eUhsRDZObVJnME4rUT09)

I consider the "breakpoint" (x -> xi) region in DVCS, DVMP and exclusive photoproduction of a pi0gamma pair with large invariant mass in the framework of the CSS formalism. The corresponding subtleties in the factorization proofs of DVCS and DVMP are discussed. The exclusive photoproduction of a pi0gamma pair with large invariant mass (and similar 2 -> 3 processes) have recently been proposed to access the x-dependence of GPDs beyond the moment-type information. I show that collinear factorization is broken by a Glauber contribution in the gluon channel. I further conclude that collinear factorization should hold for certain mesons (e.g. charged pions) that forbid the gluon channel.