Contents. Introduction NLO Calculations Numerical Results Summary. Introduction. A great amount of interests has been triggered by the observation of several double-charmonium production in two B factories several years ago.
(1) NLO perturbative Calculations for process:
(2) NLO both perturbative and relativistic Calculations for process:
Helicity Selection Rule:
v denotes the characteristic velocity of charm quark inside a charmonium.
Slowest asymptotic decrease:
Total Cross Sections:
Agree with E. Braaten and J. Lee (2005)
The I.R. divergence will be absorbed into the Matrix Elements:
Numerical Plot of the finite part:
If we set
generally, the integer l, m and n are larger than 1.
and FIRE package will reduce these integer to 1 or 0, i.e. Master Integrals (MI), through Integral By Part (IBP).