https://doi.org/10.1140/epjc/s10052-017-5365-9
Letter
A case study of quark-gluon discrimination at NNLL
in comparison to parton showers
1
Institute for Theoretical Physics Amsterdam and Delta Institute for Theoretical Physics, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
2
Nikhef, Theory Group, Science Park 105, 1098 XG, Amsterdam, The Netherlands
3
Theory Group, Deutsches Elektronen-Synchrotron (DESY), 22607, Hamburg, Germany
* e-mail: w.j.waalewijn@uva.nl
Received:
8
August
2017
Accepted:
3
November
2017
Published online:
16
November
2017
Predictions for our ability to distinguish quark and gluon jets vary by more than a factor of two between different parton showers. We study this problem using analytic resummed predictions for the thrust event shape up to NNLL using 
and 
as proxies for quark and gluon jets. We account for hadronization effects through a nonperturbative shape function, and include an estimate of both perturbative and hadronization uncertainties. In contrast to previous studies, we find reasonable agreement between our results and predictions from both Pythia and Herwig parton showers. We find that this is due to a noticeable improvement in the description of gluon jets in the newest Herwig 7.1 compared to previous versions.
© The Author(s), 2017
