D. De Florian et M. Grazzini, Next-to-next-to-leading-order logarithmic corrections at small transverse momentum in hadronic collisions, PHYS REV L, 85(22), 2000, pp. 4678-4681
We study the region of small transverse momenta in q (q) over bar- and gg-i
nitiated processes with no colored particle detected in the final state. We
present the universal expression of the O(alpha (2)(s)) logarithmically en
hanced contributions up to next-to-next-to-leading-order logarithmic accura
cy. From there we extract the coefficients that allow the resummation of th
e large logarithmic contributions. We find that the coefficient known in th
e literature as B-(2) is process dependent, since it receives a hard contam
ination from the one-loop correction to the leading-order subprocess. We pr
esent the general result of B-(2) for both quark and gluon channels.