In:
Journal of High Energy Physics, Springer Science and Business Media LLC, Vol. 2012, No. 7 ( 2012-07)
Abstract:
We present measurements of Underlying Event observables in pp collisions at $ \sqrt {s} = 0.9 $ and 7TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p T,LT in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p T thresholds: 0.15, 0.5 and 1.0 GeV /c . In the Transverse region we observe an increase in the multiplicity of a factor 2–3 between the lower and higher collision energies, depending on the track p T threshold considered. Data are compared to P ythia 6.4, P ythia 8.1 and P hojet . On average, all models considered underestimate the multiplicity and summed p T in the Transverse region by about 10–30%.
Type of Medium:
Online Resource
ISSN:
1029-8479
DOI:
10.1007/JHEP07(2012)116
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2012
detail.hit.zdb_id:
2027350-2
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