  We present a new QCD description of the ATLAS jet veto measurement, using the
Banfi-Marchesini-Smye equation to constrain the inter-jet QCD radiation. This
equation resums emissions of soft gluons at large angles, at
leading-logarithmic accuracy, and accounts for both the so-called Sudakov and
non-global logarithms. We show that this approach is able to reproduce, with no
fitting parameters, the fraction of high-pT forward/backward di-jet events
which do not contain additional hard emissions in the inter-jet rapidity range.
We also compute the gap fraction in fixed-order perturbation theory to
O(alpha_s^2) and show that the perturbative series is unstable at large
rapidity intervals.
