Dijet production with a large rapidity gap between the jets

Events with no particles produced between two leading jets have been studied in pp collisions at $\sqrt{s}=7$ TeV, for jets with $p_\mathrm{T}>40$ GeV and $1.5<|\eta|<4.5$, reconstructed in opposite hemispheres of the detector. The ratio of the yield for these large rapidity gap events to that for inclusive dijet events has been measured as a function of the transverse momentum of the second-leading jet and the size of the pseudorapidity interval between the jets. The observed excess of events with no charged particles between the jets is consistent with the presence of hard color-singlet exchange. The measurement is based on 8 pb$^{-1}$ of integrated luminosity collected with the CMS detector in 2010.