Central jet production as a probe of the perturbative formalism for   exclusive diffraction
  We propose a new variable, R_j, in order to identify exclusive double-diffractive high E_T dijet production. The variable R_j is calculated using the transverse energy E_T and pseudorapidity of the jet with the largest E_T. For a purely exclusive event the value of R_j -> 1, if we were to neglect hadronisaton and the detector resolution effects. To illustrate the expected R_j-distribution we also compute exclusive three-jet production; and, moreover, include jet smearing effects. By studying the predictions as a function of the size of the rapidity interval, delta(eta), which allows for additional gluon radiation, one can probe the QCD radiation effects which are responsible for the Sudakov suppression of the exclusive amplitude. In this way we may check, and improve, the formalism used to predict the cross sections of exclusive double-diffractive Higgs boson (and/or other New Physics) production. 
V.A. Khoze, A.D. Martin and M.G. Ryskin