Jet invariant mass in quantum chromodynamics

We give a heuristic argument that a new class of observables related to the invariant mass of jets in e⁺e^- annihilation is infrared finite to all orders of perturbation theory in Quantum Chromodynamics. We calculate the lowest order QCD predictions for the mass distribution as well as for the double differential cross section to produce back to back jets of invariant mass M₁ and M₂. The resulting cross sections are quite different from that expected in simple hadronic fireball models and should provide experimentally accessible tests of QCD.

We acknowledge discussions on this work with G. Branco, H.P. Nilles and V. Rittenburg at the University of Bonn.