First measurement of the underlying event activity at the LHC with sqrt{s} = 0.9 TeV
Abstract
A measurement of the underlying activity in scattering processes with p T scale in the GeV region is performed in proton-proton collisions at sqrt{s} = 0.9 TeV, using data collected by the CMS experiment at the LHC. Charged particle production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD-inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production of charged particles with pseudorapidity | η|<2, p T >0.5 GeV/ c, and azimuthal direction transverse to that of the leading object.
- Publication:
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European Physical Journal C
- Pub Date:
- December 2010
- DOI:
- 10.1140/epjc/s10052-010-1453-9
- arXiv:
- arXiv:1006.2083
- Bibcode:
- 2010EPJC...70..555K
- Keywords:
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- High Energy Physics - Experiment
- E-Print:
- Eur.Phys.J.C70:555-572,2010