XXVIII International Workshop on Deep-Inelastic Scattering and Related Subjects

Hard color-singlet exchange in dijet events in proton-proton collisions at sqrt(s) = 13 TeV in CMS and TOTEM

13 Apr 2021, 10:19

18m

Virtual (Stony Brook, NY)

Contributed Talk Small-x, Diffraction and Vector Mesons Small-x, Diffraction and Vector Mesons

Speaker

Cristian Baldenegro Barrera (University of Kansas)

Description

This paper presents an experimental study of proton-proton collision events where the two leading jets are separated by a large pseudorapidity interval devoid of particle activity, referred to as jet-gap-jet events. The pseudorapidity gap is expected from hard color-singlet exchange. The analysis is based on data collected by the CMS and TOTEM experiments during a low luminosity, high-${\beta }^{\ast }$ run at the CERN LHC in 2015. Events with a low number of charged particles between the jets are observed in excess of calculations that assume only color-exchange dijet contributions. The fraction of dijet events produced via color-singlet exchange, $f_{\text{CSE}}$, is measured as a function of $p_{\text{T}}^{\text{jet2}}$, the pseudorapidity difference between the two leading jets, and the azimuthal angular separation between the two leading jets. The fraction $f_{\text{CSE}}$ has values of $0.6$--$1.0$\%. It increases with the pseudorapidity difference between the jets, has a weak dependence on $p_{\text{T}}^{\text{jet2}}$, and increases as the azimuthal angular difference between the jets approaches $\pi$. The results are compared with previous measurements and with predictions from perturbative quantum chromodynamics. In addition, the paper presents the first study of jet-gap-jet events detected in association with an intact proton, interpreted as a proton-gap-jet-gap-jet topology, using a subsample of events with an integrated luminosity of $0.40{\text{pb}}^{-1}$. The intact protons are detected with the Roman pot detectors of the TOTEM experiment. The $f_{\text{CSE}}$ measured in this sample is $2.91\pm 0.70$ (stat) ${}_{-0.94}^{+1.02}$ (syst) times larger than that for inclusive dijet production in dijets with similar kinematics.

Presentation materials

cbaldenegro_dis2021.pdf

Youtube Link