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 s**(1/2) = 1800 GeV and s**(1/2) =
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 pseudo-rapidity, eta, as the
jet with the highest transverse energy (E(1)_T), and at +/-900 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(1)_T and is similar to the momentum observed in minimum
bias events, whereas the maximum momentum increases roughly linearly with
the jet E(1)_T over most of the measured range. This 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 in also examined for five different E(1)_T bins.
The HERWIG and PYTHIA Monte Carlos are reasonably successful in describing
the data, but neither can describe completely all of the event properties.
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Updated: Thursday, 2004 October 28 10:24:15 CDT automatically from input from "Carol I. Picciolo"