Observation of a diffractive contribution to dijet production in proton-proton collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports the first observation at the LHC of a significant diffractive contribution to dijet production in proton-proton collisions at 7 TeV, using CMS data and comparing to theoretical models.

Contribution

It provides the first measurement of diffractive dijet production at the LHC and estimates the rapidity gap survival probability.

Findings

Significant diffractive dijet contribution observed

Data agrees with diffractive model predictions

Rapidity gap survival probability estimated

Abstract

The cross section for dijet production in pp collisions at sqrt(s) = 7 TeV is presented as a function of xi, a variable that approximates the fractional momentum loss of the scattered proton in single-diffractive events. The analysis is based on an integrated luminosity of 2.7 inverse nanobarns collected with the CMS detector at the LHC at low instantaneous luminosities, and uses events with jet transverse momentum of at least 20 GeV. The dijet cross section results are compared to the predictions of diffractive and nondiffractive models. The low-xi data show a significant contribution from diffractive dijet production, observed for the first time at the LHC. The associated rapidity gap survival probability is estimated.