Monday, July 23, 2012

1207.4788 (Ambar Jain et al.)

Fragmentation with a Cut on Thrust: Predictions for B-factories    [PDF]

Ambar Jain, Massimiliano Procura, Brian Shotwell, Wouter J. Waalewijn
The inclusion of B-factory data in fragmentation function analyses will improve the precision with which these are known. To remove the large b-quark contribution from on-resonance data, a cut on the thrust event shape T is used, leading to a dijet final state. Here we complete our analysis of unpolarized fragmentation of (light) quarks and gluons to a light hadron h with energy fraction z in e+ e- -> dijet + h at the center-of-mass energy Q=10.52 GeV. In addition to the next-to-next-to-leading order resummation of logarithms of 1-T, we include the next-to-leading order (NLO) nonsingular O(1-T) contribution to the cross section, the resummation of threshold logarithms of 1-z, and the leading nonperturbative contribution to the soft function. Our results can be directly used to study correlations between fragmentation and the thrust cut imposed on B-factory data, which must be taken into account to extract fragmentation functions with reliable uncertainties. These correlations are also observed in Pythia, but are surprisingly smaller at NLO.
View original: http://arxiv.org/abs/1207.4788

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