Elastic double diffractive production of axial-vector χc (1+ +) mesons and the Landau-Yang theorem
We discuss exclusive elastic double diffractive axial-vector χc (1+) meson production in proton-antiproton collisions at the Tevatron. The amplitude for the process is derived within the kt-factorization 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 diff
