Measurement of event shapes in <em>pp</em> collisions at √s=1.96  TeV

CDF Collaboration

doi:10.1103/PhysRevD.83.112007

Scientific article

English

Measurement of event shapes in pp collisions at √s=1.96 TeV

Contributors

CDF Collaboration

Collaborators

Clark, Allan Geoffrey; Garcia Navarro, Jose Enrique; Lister, Alison; Wu, Xin

Published in

Physical review. D. Particles, fields, gravitation, and cosmology, vol. 83, no. 11, 112007

Publication date

2011

Abstract

A study of event-shape observables in proton-antiproton collisions at s√=1.96 TeV is presented. The data for this analysis were recorded by the CDF II Detector at the Tevatron Collider. The variables studied are the transverse thrust and thrust minor, both defined in the plane perpendicular to the beam direction. The observables are measured using energies from unclustered calorimeter cells. In addition to studies of the differential distributions, we present the dependence of event-shape mean values on the leading-jet transverse energy. Data are compared with pythia Tune A and to resummed parton-level predictions that were matched to fixed-order results at next-to-leading-order (NLO) accuracy (NLO+NLL). Predictions from pythia Tune A agree fairly well with the data. However, the underlying event contributes significantly to these observables, making it difficult to make direct comparisons to the NLO+NLL predictions, which do not account for the underlying event. To overcome this difficulty, we introduce a new observable, a weighted difference of the mean values of the thrust and thrust minor, which is less sensitive to the underlying event, allowing for a comparison with NLO+NLL. Both pythia Tune A and the NLO+NLL calculations agree well within the 20% theoretical uncertainty with the data for this observable, indicating that perturbative QCD successfully describes shapes of the hadronic final states.

UNIGE affiliation entities

Faculté des sciences / Section de physique / Département de physique nucléaire et corpusculaire

Citation (ISO format)

CDF Collaboration. Measurement of event shapes in pp collisions at √s=1.96 TeV. In: Physical review. D. Particles, fields, gravitation, and cosmology, 2011, vol. 83, n° 11, p. 112007. doi: 10.1103/PhysRevD.83.112007

Article (Published version)

Identifiers

PID : unige:38671
DOI : 10.1103/PhysRevD.83.112007

Additional URL for this publication

http://journals.aps.org/prd/abstract/10.1103/PhysRevD.83.112007

Journal ISSN

1550-2368

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143downloads

Creation

15/07/2014 13:39:00

First validation

15/07/2014 13:39:00

Update

13/10/2025 22:32:43

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14/03/2023 21:26:48

Last indexation

10/11/2026 17:01:19