Jet measurements at DO using a KT algorithm

TL;DR

This paper reports the implementation of a KT jet algorithm at the DO experiment, presenting measurements of subjet multiplicity, inclusive jet cross section, and thrust, with results aligning with some theoretical predictions and highlighting areas for theoretical improvement.

Contribution

First application of a KT jet algorithm at a ppbar collider, providing new measurements and comparisons with QCD predictions.

Findings

Subjet multiplicity ratio matches theoretical expectations.

NLO pQCD predictions agree with measured jet cross sections.

Preliminary thrust measurements suggest need for higher-order calculations.

Abstract

DO has implemented and calibrated a KT jet algorithm for the first time in a ppbar collider. We present two results based on 1992-1996 data which were recently published: the subjet multiplicity in quark and gluon jets and the central inclusive jet cross section. The measured ratio between subjet multiplicities in gluon and quark jets is consistent with theoretical predictions and previous experimental values. NLO pQCD predictions of the KT inclusive jet cross section agree with the DO measurement, although marginally in the low pT range. We also present a preliminary measurement of thrust cross sections, which indicates the need to include higher than alpha_s^3 terms and resumation in the theoretical calculations.