Measurement of the Jet Mass Distribution and Top Quark Mass in Hadronic Decays of Boosted Top Quarks in $pp$ Collisions at $\sqrt{s} =$ TeV

The collaboration
Phys.Rev.Lett. 124 (2020) 202001, 2020.

Abstract (data abstract)
A measurement is reported of the jet mass distribution in hadronic decays of boosted top quarks produced in \pp collisions at $\sqrt{s}=13\,\mathrm{TeV}$. The data were collected with the CMS detector at the LHC and correspond to an integrated luminosity of $35.9\,\mathrm{fb}^{-1}$. The measurement is performed in the lepton+jets channel of $\mathrm{t}\overline{\mathrm{t}}$ events, where the lepton is an electron or muon. The products of the hadronic top quark decay $\mathrm{t} \rightarrow \mathrm{b}\mathrm{W} \rightarrow \mathrm{b}\mathrm{q}\mathrm{q}'$ are reconstructed as a single jet with transverse momentum larger than $400\,\mathrm{GeV}$. The $\mathrm{t}\overline{\mathrm{t}}$ cross section as a function of the jet mass is unfolded at the particle level and used to extract a value of the top quark mass of $172.6 \pm 2.5\,\mathrm{GeV}$. A novel jet reconstruction technique is used for the first time at the LHC, which improves the precision by a factor of three relative to an earlier measurement. This highlights the potential of measurements using boosted top quarks, where the new technique will enable future precision measurements.

• #### Figure 2 a

Contents of Figure 2a

10.17182/hepdata.93067.v2/t1

The particle-level $\mathrm{t}\overline{\mathrm{t}}$ differential cross section in the fiducial region as a function of the XCone-jet mass.

• #### Figure 2 b

Contents of Figure 2b

10.17182/hepdata.93067.v2/t2

The normalized particle-level $\mathrm{t}\overline{\mathrm{t}}$ differential cross section in the fiducial region as a function of the XCone-jet mass.

• #### Figure 2a Stat Covariances

Covariances of stat uncertainties of Figure 2a

10.17182/hepdata.93067.v2/t3

The covariance matrix containing the statistical uncertainties of Figure 2a is shown.

• #### Figure 2a Experimental Covariances

Covariances of exp uncertainties of Figure 2a

10.17182/hepdata.93067.v2/t4

The covariance matrix containing the experimental uncertainties of Figure 2a is shown.

• #### Figure 2a Model Covariances

Covariances of model uncertainties of Figure 2a

10.17182/hepdata.93067.v2/t5

The covariance matrix containing the model uncertainties of Figure 2a is shown.

• #### Figure 2b Stat Covariances

Covariances of stat uncertainties of Figure 2b

10.17182/hepdata.93067.v2/t6

The covariance matrix containing the statistical uncertainties of Figure 2b is shown.

• #### Figure 2b Experimental Covariances

Covariances of exp uncertainties of Figure 2b

10.17182/hepdata.93067.v2/t7

The covariance matrix containing the experimental uncertainties of Figure 2b is shown.

• #### Figure 2b Model Covariances

Covariances of model uncertainties of Figure 2b

10.17182/hepdata.93067.v2/t8

The covariance matrix containing the model uncertainties of Figure 2b is shown.

Version 2 modifications: HEPdata entry edited to make it compatible with the Rivet routine. The changes are listed below. - removed Figure 1 since this is not part of the measurement - added bin edges in Figure 2a and Figure 2b