Investigation of the scale dependence in the MSR and $\overline{\textrm{MS}}$ top quark mass schemes for the $\mathrm{t}\overline{\mathrm{t}}$ invariant mass differential cross section using LHC data

Abstract

The computation of the single-differential top quark-antiquark pair ($\mathrm{t}\overline{\mathrm{t}}$) production cross section at NLO in the fixed-order expansion is examined consistently using the MSR and $\overline{\textrm{MS}}$ short-distance top quark mass schemes. A thorough investigation of the dependence of different regions of the $\mathrm{t}\overline{\mathrm{t}}$ invariant mass spectrum on the renormalization scales $R$ and $\mu_m$ of the MSR mass $m_\mathrm{t}^{\textrm{MSR}}(R)$ and $\overline{\textrm{MS}}$ mass $\overline{m}_\mathrm{t}(\mu_m)$, respectively, is carried out. We demonstrate that a scale choice of $R\sim 80$~GeV is important for the stability of the cross-section predictions for the low $\mathrm{t}\overline{\mathrm{t}}$ invariant mass range, which is important for a reliable extraction of the top quark mass. Furthermore, a choice of semi-dynamical renormalization and factorization scales is preferred. These findings are expected to remain valid once non-relativistic quasi-bound state effects are included in the low invariant mass region.