Experimental study of the emergence of two-jet dominance in p‾\overline{p}p collisions at s\sqrt{s} = 630 GeV

A heuristic model is used to describe data collected by the UA2 experiment at √s = 630 GeV. Distributions of the energy sharing between the leading clusters and the rest of the event are examined. The main features of these distributions can be described by a two-component model with soft, collective interactions dominating at low transverse energy and hard, constituent interactions dominating at high transverse energy. This model provides a simple picture of the emergence of two-jet dominance at SPS pp Collider energies. © 1985

Direct photon production at the CERN p‾\overline{p}p collider

Using the UA2 apparatus, the inclusive cross section has been measured for production of high-pT direct photons in p̄p collisions at s=546 GeV and s=630 GeV. The results are in good agreement with QCD predictions. © 1986

Measurement of the s\sqrt{s} dependence of jet production at the CERN p‾\overline{p}p collider

The production of very large transverse momentum (pT) hadron jets has been measured in the UA2 experiment at the CERN pp Collider for s=630 GeV. The inclusive jet production cross sections exhibit a pT-dependent increase with respect to the s=546 GeV data from previous Collider runs. This increase can be described both by QCD calculations and by approximate xT=2pT/√s scaling. No significant deviation of the data from QCD predictions is observed at very large pT, placing a lower limit on the characteristic scale Λc of a hypothetical superstrong contact interaction responsible for the binding of preons in the quark (Λc>370 GeV at 95% CL). © 1985