Associated transverse energy in hadronic jet production

We present a theoretical study of the ``pedestal height'' in hadronic jet production, i.e., the mean transverse energy per unit of rapidity 〈ωTped〉 accompanying a high-transverse-energy jet. We find that perturbative QCD, supplemented by a Monte Carlo estimate of higher-order corrections and a soft underlying event structure similar to that of minimum-bias collisions, can account for the observed pedestal height and its dependence on jet transverse energy. We propose a way of separating the hard pedestal contribution from that of the underlying event by measuring the quantity 〈ωTdif〉, which is one-half the absolute difference of the pedestal heights on the two sides of the jet. This quantity is dominated by the hard QCD component, whereas 〈ωT^min〉=〈ωTped〉 -〈ωTdif〉 is dominated by the soft underlying event. We also discuss the differential distribution of pedestal height and the charged multiplicity in the pedestal.