A measurement of the ratio of inclusive cross sections $\sigma(p\bar{p}\rightarrow Z+b{\rm\, jet})/ \sigma(p\bar{p}\rightarrow Z+{\rm jet})$ at $\sqrt{s}=1.96$ TeV

TL;DR

This paper precisely measures the ratio of cross sections for Z boson production with b jets versus inclusive Z+jet events at the Tevatron, using a novel track-based discrimination technique.

Contribution

It introduces a new method to discriminate b jets from charm and light jets, achieving the most precise measurement of this ratio to date.

Findings

Measured ratio: 0.0193 ± 0.0027

Results are consistent with theoretical predictions

First measurement using this novel discrimination technique

Abstract

The ratio of the cross section for $p\bar{p}$ interactions producing a $Z$ boson and at least one $b$ quark jet to the inclusive $Z+{\rm jet}$ cross section is measured using $4.2\ {\rm fb}^{-1}$ of $p\bar{p}$ collisions collected with the \dzero\ detector at the Fermilab Tevatron collider at $\sqrt{s}=1.96$ TeV. The $Z\rightarrow\ell^+\ell^-$ candidate events with at least one $b$ jet are discriminated from $Z+$ charm and light jet(s) events by a novel technique that exploits the properties of the tracks associated to the jet. The measured ratio is $0.0193\pm0.0027$ for events having a jet with transverse momentum $\pt > 20 \GeV$ and pseudorapidity $|\eta| \leq 2.5$, which is the most precise to date and is consistent with theoretical predictions.