Exclusive production of ω mesons was studied at the COMPASS experiment by scattering 160 GeV/c muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured in the range of photon virtuality 1 (GeV/c)2<Q2<10 (GeV/c)2, Bjorken scaling variable 0.003<xBj<0.3 and transverse momentum squared of the ω meson 0.05 (GeV/c)2<pT 2<0.5 (GeV/c)2. The measured asymmetries are sensitive to the nucleon helicity-flip Generalised Parton Distributions (GPD) E that are related to the orbital angular momentum of quarks, the chiral-odd GPDs HT that are related to the transversity Parton Distribution Functions, and the sign of the πω transition form factor. The results are compared to recent calculations of a GPD-based model.
ASJC Scopus subject areas
- Nuclear and High Energy Physics