  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.
