Freiburg 2008 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 24: QCD I

T 24.6: Vortrag

Dienstag, 4. März 2008, 18:00–18:15, KGI-HS 1032

Z+jet Measurements at D0, Tevatron - Comparing with Event Generators — •Henrik Nilsen and Ralf Bernhard — Physikalisches Institut, Hermann-Herder-Str.3, D-79104 Freiburg

Boson+jet production will be a major background to many searches and measurements at the LHC. While inclusive boson production is well understood, uncertainties become large if one tags one or more QCD jets in the event.

During the last few years a new category of event generators which match Parton Shower and Matrix Element predictions for QCD radiation have been developed. Examples are Sherpa and Alpgen.

This type of event generators have an uncertainty of 20-30% for the prediction of boson pT at Tevatron and about 1.25^N for jet multiplicity, where N is the number of jets (arXiv:0706.2569). To get better accuracy than this one needs to tune to data or more precise theory. Measurements of pT(boson) in an inclusive sample at Tevatron have been done at RunI and II of Tevatron, but there is a lack of measurements of exclusive jet-related observables. Such measurements would be useful for the developers of event generators to facilitate better tunings for the early stage of the LHC.

The aim of the study presented in this talk is to measure jet-related observables in Z+jet events with the D0 detector at Tevatron. These measurements are compared to the predictions of various event generators available. In addition more general experiences about low-pT jets and the boson+jet channels at Tevatron will be presented.