# Measurement of $b$-hadron pair production with the ATLAS detector in proton-proton collisions at $\sqrt{s}=8$ TeV

## TL;DR

This paper measures the production rate of $b$-hadron pairs in proton-proton collisions at 8 TeV using the ATLAS detector, providing data to test and constrain theoretical models of heavy flavor production.

## Contribution

It presents the first detailed measurement of $b$-hadron pair production cross sections in a specific kinematic region at 8 TeV, comparing results to multiple event generator predictions.

## Key findings

- Measured fiducial cross section: 17.7 ± 0.1 (stat) ± 2.0 (syst) nb.
- Provided differential cross sections for $b$-hadron pairs.
- Compared measurements with predictions from Pythia8, Herwig++, MadGraph5_aMC@NLO+Pythia8, and Sherpa.

## Abstract

A measurement of $b$-hadron pair production is presented, based on a data set corresponding to an integrated luminosity of 11.4 fb$^{-1}$ of proton--proton collisions recorded at $\sqrt{s}=8$ TeV with the ATLAS detector at the LHC. Events are selected in which a $b$-hadron is reconstructed in a decay channel containing $J/\psi \rightarrow \mu\mu$, and a second $b$-hadron is reconstructed in a decay channel containing a muon. Results are presented in a fiducial volume defined by kinematic requirements on three muons based on those used in the analysis. The fiducial cross section is measured to be $17.7 \pm 0.1 ($stat.$) \pm 2.0 ($syst.$)$ nb. A number of normalised differential cross sections are also measured, and compared to predictions from the Pythia8, Herwig++, MadGraph5\_aMC@NLO+Pythia8 and Sherpa event generators, providing new constraints on heavy flavour production.