Large transverse momenta: colliders and cosmic rays

The CERN anti pp collider has extended the transverse momentum (P sub(T)) range over which QCD can be tested by over one order of magnitude. We have reached a domain in P sub(T) where calculations are relatively straightforward and experimental signatures for jets dramatic: we show how the theory survives the challenge. We also point out how at high energies ''large'' P sub(T) events occur with increased cross section and eventually affect the global structure of the interactions. As a result of this (i) < P sub(T) > increases (and this increase is associated with events with higher than average multiplicity), (ii) the secondaries can have large invariant masses as a kinematic reflection of large P sub(T), (iii) the total cross section increases with energy, and, most importantly, (iv) Feynman scaling is inevitably violated, even if it is approximately valid at lower energies. These conclusions must be important for the interpretation of cascade experiments around 1015 eV and above. (author)