Exclusive double quarkonium production and generalized TMDs of gluons

Abstract

Being the "mother distributions" of all types of two-parton correlation functions, generalized transverse momentum dependent parton distributions (GTMDs) have attracted a lot of attention over the last years. We argue that exclusive double production of pseudoscalar quarkonia (${\eta }_c$ or ${\eta }_b$) in nucleon-nucleon collisions gives access to GTMDs of gluons.

Comments: 7 pages