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).
Physics Letters. Section B: Nuclear, Elementary Particle and High-energy Physics, 1985, Vol 160, Issue 4-5, p. 349-356