Hard inclusive production of a pair of rapidity-separated hadrons in   proton collisions
  We discuss the process $p+p\to h_1+h_2+X$, where the identified hadrons $h_1$ and $h_2$ have large transverse momenta and are produced in high-energy proton-proton collisions with a large rapidity gap between them. In this case the (calculable) hard part of the reaction receives large higher order corrections $\sim \alpha^n_s\ln^n \Delta y$, which can be accounted for in the BFKL approach. Specifically, we describe in the next-to-leading order the calculation of the vertex (impact-factor) for the inclusive production of the identified hadron. 
Dmitry Yu. Ivanov and Alessandro Papa
hep-ph