Elastic double diffractive production of axial-vector \chi_c(1^{++}) mesons and the Landau-Yang theorem

Understand

We discuss exclusive elastic double diffractive axial-vector \chi_c(1^{+}) meson production in proton-antiproton collisions at the Tevatron.

• The amplitude for the process is derived within the k_t-factorisation approach with unintegrated gluon distribution functions (UGDFs).
• We show that the famous Landau-Yang theorem is not applicable in the case of off-shell gluons.
• Differential cross sections for different UGDFs are calculated.