Dijets with a large rapidity separation in the next-to-leading order BFKL formalism for searches of large extra dimensions at colliders

TL;DR

This paper investigates high-mass dijet production with large rapidity separation at colliders, using NLL BFKL formalism to distinguish signals of large extra dimensions from QCD background.

Contribution

It provides the first detailed NLL BFKL calculation of the QCD background for large extra dimension searches in dijet events at colliders.

Findings

Quantitative estimates of the QCD background at HL-LHC and future colliders.

Assessment of the potential to detect large extra dimensions via dijet observables.

Comparison of signal and background to guide experimental searches.

Abstract

Search for the gravity with large extra dimensions at collider energies is considered in the trans-Planckian eikonal regime, i.e., when $\sqrt{\hat{s}} \gg M_D \gg \sqrt{-\hat{t}}$. Here $\hat{s}$ and $\hat{t}$ are the Mandelstam variables of colliding parton-parton system and $M_D$ is the Planck mass scale in the space-time with compactified $n_D$ extra dimensions. A relevant observable for this regime may be the cross section of high-mass ($M_{jj}\sim\sqrt{\hat{s}} \gg M_D$) dijet production with a large rapidity separation. Then the standard model background should be calculated within the next-to-leading logarithmic (NLL) approximation of Lipatov-Fadin-Kuraev-Balitsky (BFKL) formalism of quantum chromodynamics (QCD) suitable for $\sqrt{\hat{s}}\gg\sqrt{-\hat{t}}\gg\Lambda_\mathrm{QCD}$. In this work the signal of the large extra dimension gravity as well as the NLL BFKL QCD background are estimated for the high-luminosity Large Hadron Collider (HL-LHC) and future colliders such as FCCpp and CEPC-SppC.