Hard color-singlet exchange in dijet events in proton-proton collisions at $\sqrt{s} = 13$ TeV

Abstract

We present a measurement of events with two jets separated by a pseudorapidity gap (jet-gap-jet). The signature is expected from hard color-singlet exchange. The jets are reconstructed with the CMS detector. The highest p_\text{T}pT jets have p_\text{T}^\text{jet1,2} > 40pTjet1,2>40 GeV, with 1.4 < |\eta^\text{jet1,2}| < 4.71.4<|ηjet1,2|<4.7 and \eta^\text{jet1} \eta^\text{jet2} < 0ηjet1ηjet2<0. We measure the fraction of color-singlet exchange dijet events, f_\text{CSE}fCSE, and compare it to previous measurements and to predictions. We also study jet-gap-jet events where the colliding protons remain intact and are detected with the Roman pots of TOTEM. A larger fraction f_\text{CSE}fCSE is found in the latter subsample.