# Measurement of the top quark mass in the all-jets final state at $\sqrt{s} =$ 13 TeV and combination with the lepton+jets channel

## TL;DR

This paper measures the top quark mass using all-jets final state data at 13 TeV with the CMS detector, and combines it with lepton+jets results for a more precise estimate.

## Contribution

It introduces a combined measurement of the top quark mass from all-jets and lepton+jets channels using a unified likelihood approach.

## Key findings

- Top quark mass measured as 172.34 GeV in all-jets channel.
- Combined top quark mass from both channels is 172.26 GeV.
- First combined measurement using a single likelihood function.

## Abstract

A top quark mass measurement is performed using 35.9 fb$^{-1}$ of LHC proton-proton collision data collected with the CMS detector at $\sqrt{s} =$ 13 TeV. The measurement uses the $\mathrm{t\overline{t}}$ all-jets final state. A kinematic fit is performed to reconstruct the decay of the $\mathrm{t\overline{t}}$ system and suppress the multijet background. Using the ideogram method, the top quark mass ($m_\mathrm{t}$) is determined, simultaneously constraining an additional jet energy scale factor (JSF). The resulting value of $m_\mathrm{t}$ = 172.34 $\pm$ 0.20 (stat+JSF) $\pm$ 0.70 (syst) GeV is in good agreement with previous measurements. In addition, a combined measurement that uses the $\mathrm{t\overline{t}}$ lepton+jets and all-jets final states is presented, using the same mass extraction method, and provides an $m_\mathrm{t}$ measurement of 172.26 $\pm$ 0.07 (stat+JSF) $\pm$ 0.61 (syst) GeV. This is the first combined $m_\mathrm{t}$ extraction from the lepton+jets and all-jets channels through a single likelihood function.