Recent forward physics and diffraction results from CMS

Abstract

Recent CMS results on forward physics and diffraction are reviewed. The differential diffractive cross section is measured as a function of ξ = M2X/S in the region dominated by single dissociation (SD) and double dissociation (DD), where MX is the mass of one of the two final-state hadronic systems separated by the largest rapidity gap in the event. The total SD and DD cross sections are extracted. The observation of a hard color-singlet exchange process in events with a large rapidity gap between two leading jets (jet-gap-jet) is reported. The fraction of jet-gap-jet to all dijet events is measured as a function of the second leading jet transverse momentum and the size of the pseudorapidity gap. The measured fractions are compared with predictions as well as Tevatron data.