Multiplicity of (Mini-)Jets at Small x

TL;DR

This paper derives formulas for the average and variance of mini-jet multiplicities in low-x hard scattering processes, including sub-leading logarithms, and applies these to Higgs production at the LHC.

Contribution

It provides the first closed-form expressions for mini-jet multiplicity moments at low x, incorporating all sub-leading logarithms of Q^2/m_R^2.

Findings

Predicted mini-jet multiplicity in Higgs production at LHC

Derived formulas valid to leading order in log(1/x)

Included all sub-leading logarithms of Q^2/m_R^2

Abstract

We derive closed expressions for the mean and variance of the (mini-)jet multiplicity distribution in hard scattering processes at low x. Here (mini-)jets are defined as those due to initial-state radiation of gluons with transverse momenta greater than some resolution scale m_R, where Lambda^2 << m_R^2 << Q^2, Lambda being the intrinsic QCD scale and Q the momentum transfer scale of the hard scattering. Our results are valid to leading order in log(1/x) but include all sub-leading logarithms of Q^2/m_R^2. As an illustration, we predict the mini-jet multiplicity in Higgs boson production at the Large Hadron Collider.