Jet Multiplicity Distributions Research Articles

Single jet structure ine + e ? annihilation

By using JETSET 7.2 ase+e− event generator at different c.m. energies, we studiedsingle jet multiplicity distributions in different rapidity andpT intervals. Good NB behavior is found and related clan structure analysis is performed. Observed differences in the behavior of the 2-and 3-jet samples can be understood in terms of the relative contribution of single quark and gluon jet to the 3-jet sample, which are obtained by selecting event by event in this sample the highest and the lowest energy jet respectively.

QCD JET MULTIPLICITIES AT THE SSC

Jet multiplicity distributions and corresponding cross sections are calculated at the energy of the SSC collider. Their impact on the level of the 4-jet background to the WW, WZ and ZZ signals is discussed.

Determination of alpha s from a differential-jet-multiplicity distribution in e+e- collisions at sqrt s =29 and 91 GeV.

We measured the differential jet-multiplicity distribution in e+e− annihilation with the Mark II detector. This distribution is compared with the second-order QCD prediction and αs is determined to be 0.123±0.009±0.005 at √s≊MZ (at the SLAC Linear Collider) and 0.149±0.002±0.007 at √s=29 GeV (at the SLAC storage ring PEP). The running of αs between these two center-of-mass energies is consistent with the QCD prediction.Received 22 November 1989DOI:https://doi.org/10.1103/PhysRevLett.64.987©1990 American Physical Society

Top quark detection via W+ n jet measurements

In t t and W production at p p colliders, top quark semileptonic decays t→bℓ ν contribute to the same class of events as W→ℓ ν decays. The top contribution is particularly significant in n⩾2 jet events and can be observed (a) as a distortion in the ℓν transverse mass distribution below the W→ℓ ν jacobian peak if m t< M w; (b) as a systematic increase in the jet multiplicity distribution at large n for any m t; (c) as a shift in the apparent ( W+n jet) ( Z+n jet) event ratio at large n for any m t. The observation of a top quark signal in these ways does not require prior elimination of the W background.