Production of a Z boson and two jets with one heavy-quark tag

TL;DR

This paper delivers a next-to-leading-order QCD calculation for Z boson production with two jets containing heavy quarks, using a heavy-quark parton distribution function to resum collinear logs and render the computation tractable. Implemented in MCFM with dipole subtraction, the study includes multiple partonic channels and presents both exclusive and inclusive cross sections for the Tevatron and LHC. The findings show sizable NLO corrections, particularly for ZQj at the Tevatron, and quantify the impact of heavy-quark masses on specific subprocesses. These results sharpen background estimates for Higgs searches in Zh and related channels, demonstrating the efficacy of the heavy-quark PDF approach for precise standard-model backgrounds at hadron colliders.

Abstract

We present a next-to-leading-order calculation of the production of a Z boson with two jets, one or more of which contains a heavy quark (Q=c,b). We show that the cross section with only one heavy-quark jet is larger than that with two heavy-quark jets at both the Fermilab Tevatron and the CERN LHC. These processes are the dominant irreducible backgrounds to a Higgs boson produced in association with a Z boson, followed by h->bb. Our calculation makes use of a heavy-quark distribution function, which resums collinear logarithms and makes the next-to-leading-order calculation tractable.

Figures (8)

• Figure 1: Diagrams contributing to the associated production of a $Z$ boson and two high-$p_T$ heavy quarks ($Q=c,b$).
• Figure 1: Diagram contributing to the NLO correction to the associated production of a $Z$ boson and two high-$p_T$ jets, one or more of which contains a heavy quark ($Q=c,b$).
• Figure 2: Diagrams contributing to the associated production of a $Z$ boson and two high-$p_T$ jets, one of which contains a heavy quark ($Q=c,b$).
• Figure 2: Diagrams contributing to the NLO correction to the associated production of a $Z$ boson and two high-$p_T$ jets, one or more of which contains a heavy quark ($Q=c,b$).
• Figure 3: Diagrams contributing to the NLO correction to the associated production of a $Z$ boson and two high-$p_T$ jets, one or more of which contains a heavy quark ($Q=c,b$).