Determination of the $b$-quark mass $m_b$ from the angular screening effects in the ATLAS $b$-jet shape 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 $m_b=4.86_{-0.42}^{+0.49}\mathrm{GeV}$.

Comments: 16 pages, 10 figures. Version matching the published version