Underlying event in hard interactions at the Fermilab Tevatron p-barp collider

Journal Article · Fri Oct 01 00:00:00 EDT 2004 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.70.072002· OSTI ID:20705305

Acosta, D; Feild, R G; Field, R D; Klimenko, S; Konigsberg, J; Korytov, A; Mitselmakher, G; Sukhanov, A; Tsybychev, D; Wang, S M ^[1]; Affolder, T; Hill, C; Issever, C; Incandela, J; Spiropulu, M; Stuart, D ^[2]; Albrow, M G; Apollinari, G; Badgett, W; Beretvas, A ^[3]

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1. University of Florida, Gainesville, Florida 32611 (United States)
2. University of California at Santa Barbara, Santa Barbara, California 93106 (United States)
3. Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); and others

For comparison of inclusive jet cross sections measured at hadron-hadron colliders to next-to-leading order (NLO) parton-level calculations, the energy deposited in the jet cone by spectator parton interactions must first be subtracted. The assumption made at the Tevatron is that the spectator parton interaction energy is similar to the ambient level measured in minimum bias events. In this paper, we test this assumption by measuring the ambient charged track momentum in events containing large transverse energy jets at {radical}(s)=1800 GeV and {radical}(s)=630 GeV and comparing this ambient momentum with that observed both in minimum bias events and with that predicted by two Monte Carlo models. Two cones in {eta}-{phi} space are defined, at the same pseudorapidity, {eta}, as the jet with the highest transverse energy (E{sub T}{sup (1)}), and at {+-}90{sup o} in the azimuthal direction, {phi}. The total charged track momentum inside each of the two cones is measured. The minimum momentum in the two cones is almost independent of E{sub T}{sup (1)} and is similar to the momentum observed in minimum bias events, whereas the maximum momentum increases roughly linearly with the jet E{sub T}{sup (1)} over most of the measured range. This study was carried out using data from the CDF detector taken during Run 1 (1994-1995). The study will help improve the precision of comparisons of jet cross section data and NLO perturbative QCD predictions. The distribution of the sum of the track momenta in the two cones is also examined for five different E{sub T}{sup (1)} bins. The HERWIG and PYTHIA Monte Carlo generators are reasonably successful in describing the data, but neither can describe completely all of the event properties.

• OSTI ID: 20705305
• Journal Information: Physical Review. D, Particles Fields, Vol. 70, Issue 7; Other Information: DOI: 10.1103/PhysRevD.70.072002; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTIPROTONS
COMPARATIVE EVALUATIONS
FERMILAB COLLIDER DETECTOR
FERMILAB TEVATRON
GEV RANGE
INCLUSIVE INTERACTIONS
MONTE CARLO METHOD
PARTICLE RAPIDITY
PARTICLE TRACKS
PARTON MODEL
PARTONS
PERTURBATION THEORY
PROTON-ANTIPROTON INTERACTIONS
QUANTUM CHROMODYNAMICS
TRANSVERSE ENERGY