Study of dijet events with a large rapidity gap between the two leading jets in pp collisions at $\sqrt{s}$ = 7 TeV

Events with no charged particles produced between the two leading jets are studied in proton-proton collisions at $\sqrt{s}$ = 7 TeV. The jets were required to have transverse momentum $p_{\mathrm{T}}^{\text{jet}}$ > 40 GeV and pseudorapidity 1.5 $<\mathrm{\mid }{\eta }^{\text{jet}}\mathrm{\mid }<$ 4.7, and to have values of ${\eta }^{\text{jet}}$ with opposite signs. The data used for this study were collected with the CMS detector during low-luminosity running at the LHC, and correspond to an integrated luminosity of 8 pb${}^{-1}$. Events with no charged particles with $p_{\mathrm{T}}$ > 0.2 GeV in the interval -1 < $\eta$ < 1 between the jets are observed in excess of calculations that assume no color-singlet exchange. The fraction of events with such a rapidity gap, amounting to 0.5-1% of the selected dijet sample, is measured as a function of the $p_{\mathrm{T}}$ of the second-leading jet and of the rapidity separation between the jets. The data are compared to previous measurements at the Tevatron, and to perturbative quantum chromodynamics calculations based on the Balitsky-Fadin-Kuraev-Lipatov evolution equations, including different modelings of the non-perturbative gap survival probability.