Determination of the $b$-quark mass $m_b$ from the angular screening effects in the ATLAS $b$-jet shape data

TL;DR

This paper extracts the $b$-quark mass by analyzing jet shape data from ATLAS, using Monte Carlo simulations to compare with experimental results and determine the $b$-quark mass with associated uncertainties.

Contribution

It introduces a novel method to determine the $b$-quark mass by studying angular screening effects in $b$-jet shapes from $tar{t}$ events.

Findings

The $b$-quark mass is measured as 4.86 GeV with uncertainties.

Monte Carlo simulations successfully reproduce the jet shape data.

The method provides a new way to extract quark masses from collider data.

Abstract

The dependence of jet shapes in $t\bar{t}$ events on the $b$-quark mass and the strong coupling is investigated. To this end, the Pythia Monte Carlo generator is used to produce samples of $t\bar{t}$ events in $pp$ collisions at $\sqrt{s} = 7 \ \mathrm{TeV}$, performing a scan over the values for the shower QCD scale $\Lambda_s$ and the $b$-quark mass $m_b$. The obtained jet shapes are compared with recently published data from the ATLAS collaboration. From fits to the light-jet data, the Monte Carlo shower scale is determined, while the $b$-quark mass is extracted using the $b$-jet shapes. The result for the mass of the $b$-quark is $m_b = 4.86 ^{+0.49}_{-0.42}\ \mathrm{GeV}$.