Hadron Fragmentation Inside Jets in Hadronic Collisions

Abstract

We present an analytical next-to-leading order QCD calculation of the partonic cross sections for the process $pp\rightarrow ({\text{jet}} \,h)X$, for which a specific hadron is observed inside a fully reconstructed jet. In order to obtain the analytical results, we assume the jet to be relatively narrow. We show that the results can be cast into a simple and systematic form based on suitable universal jet functions for the process. We confirm the validity of our calculation by comparing to previous results in the literature for which the next-to-leading order cross section was treated entirely numerically by Monte-Carlo integration techniques. We present phenomenological results for experiments at the LHC and at RHIC. These suggest that $pp\rightarrow ({\text{jet}} \,h)X$ should enable very sensitive probes of fragmentation functions, especially of the one for gluons.

27 pages, 9 figures. Some additions and new comparisons to data. Version to appear in Physical Review D