Convoluting jet spectra with fragmentation functions: a cross-check of the charged particle p_T spectrum

Abstract

Motivated by the excellent agreement between next-to-leading-order pQCD calculations and the inclusive jet spectra measured by CDF, we cross-check PYTHIA fragmentation functions. The convolution of the measured jet spectra with unmodified PYTHIA fragmentation functions results in reasonable agreement with the PYTHIA charged particle spectrum over the entire p_T range of interest, while there is a sizable disagreement with the measured charged particle spectrum above p_T=30 GeV/c. In an attempt to understand the source of this discrepancy, we introduce a number of increasingly different toy-model fragmentation functions for the convolution. However, even the most extreme fragmentation functions result in an underestimate of the high-p_T CDF spectrum, which remains irreconcilable with the measured jet spectra.