The correct description of the interactions between quarks and gluons in quantum chromodynamics (QCD) is a fundamental ingredient of collider physics. When the interactions occur at short distances, cross sections can be calculated in a power series of the strong coupling αs≪1. However, there are regions of phase-space where perturbative QCD (pQCD) techniques break down, even if there is a hard momentum scale to justify the use of perturbation theory. One such kinematic region is the high-energy limit of QCD, where the collision energy is much larger than any other momentum scale. In this limit, powers of logarithms of energy multiply some powers of αs in the perturbative expansion, such that they compensate for the smallness of αs. An all-orders resummation of these terms is necessary, which is done with the Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation of pQCD.
In this seminar, we present a recent measurement by CMS and TOTEM on the production of two jets separated by a large pseudorapidity interval devoid of particle activity (Mueller-Tang jets). This topology is expected from t-channel color-singlet exchange in pQCD, which should correspond to BFKL pomeron exchange in the high-energy limit of QCD.
