# KU Physics & Astronomy LOcally Organized Assembly (PALOOZA) meeting 2020-2021

23-26 February 2021
Zoom Passcode: 990417
America/Chicago timezone

## The high energy limit of strong interactions

25 Feb 2021, 17:05
20m
Zoom Link: https://kansas.zoom.us/j/92389769214 (Zoom Passcode: 990417)

#### Zoom Passcode: 990417

Zoom Link: https://kansas.zoom.us/j/92389769214 Zoom Passcode: 990417 Zoom Meeting ID: 923 8976 9214

### Speaker

Cristian Baldenegro Barrera (The University of Kansas (US))

### Description

The physics program of the CERN LHC relies on our description of the interactions of quarks and gluons, the degrees of freedom of quantum chromodynamics (QCD), in high-energy hadronic collisions. When the interactions occur at very short distances, cross sections can be calculated in a power expansion of the strong coupling, $\alpha_s \ll 1$. However, there are regions of phase-space where perturbative QCD (pQCD) techniques break down, despite there being a hard energy scale to do pQCD calculations. One such kinematic region is the high-energy limit of QCD, where the center-of-mass energy is much larger than the momentum transfer in the collision. In this limit, logarithms of energy multiply some powers of $\alpha_s$ order-by-order, such that they compensate for the smallness of $\alpha_s$. An all-orders resummation of these terms is necessary to obtain finite cross sections. This regime of QCD is described by means of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) evolution equations of pQCD.

In this talk, a recent analysis done by the author within the CMS and TOTEM experiments that addresses this regime of QCD will be presented. In this investigation, the production of two jets separated by a large interval in pseudorapidity ($\eta = \log {\Large[} \tan{\large(} \theta/2 {\large)} {\Large]}$, where $\theta$ is the angle between the particle three-momentum and the beam axis) devoid of charged particle production (jet-gap-jet) is studied. This is expected from two-gluon $t$-channel exchange in pQCD, and is expected to be described well within the BFKL formalism.

Type of contribution Oral contribution (20 minutes)

### Primary author

Cristian Baldenegro Barrera (The University of Kansas (US))