Underlying Event Studies at LHC with CMS Detector

作者：Chao Yuan^*

来源：Progress of Theoretical Physics - Supplement, 2012, 193(193): 122-126.

DOI：10.1143/ptps.193.122

A measurement of the underlying activity in scattering processes with a PT scale in the several GeV/c region is performed in proton-proton collisions at root s = 7 TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudo-rapidity vertical bar eta vertical bar < 2 and p(T) > 0.5 GeV/c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a "track-jet". A significant growth of the average multiplicity and scalar p(T) sum of those particles is observed with increasing p(T) of the leading track-jet, followed by saturation above a few GeV/c. A hardening of the multiplicity distribution, of the scalar p(T) sum distribution, and of the charged particle p(T) spectrum is also observed. For track-jet p(T) larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centre-of-mass energy increase from 0.9 to 7 TeV. Predictions of several QCD-inspired models as implemented in PYTHIA are compared to the unfolded data.

• 出版日期2012