Measurements of the differential jet cross section as a function of the jet mass in dijet events from proton-proton collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This paper presents measurements of the differential jet cross section as a function of jet mass in dijet events at 13 TeV, comparing data with Monte Carlo simulations and theoretical calculations, highlighting areas of agreement and discrepancy.

Contribution

It provides the first detailed measurement of jet mass distributions in dijet events at 13 TeV, including groomed and ungroomed jets, and compares these with advanced theoretical predictions.

Findings

Normalized cross sections agree with Monte Carlo for masses below 30% of jet pT.

Groomed jets' cross sections are measured with higher precision.

Theoretical calculations agree with data within uncertainties for certain mass ranges.

Abstract

Measurements of the differential jet cross section are presented as a function of jet mass in dijet events, in bins of jet transverse momentum, with and without a jet grooming algorithm. The data have been recorded by the CMS Collaboration in proton-proton collisions at the LHC at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 2.3 fb$^{-1}$. The absolute cross sections show slightly different jet transverse momentum spectra in data and Monte Carlo event generators for the settings used. Removing this transverse momentum dependence, the normalized cross section for ungroomed jets is consistent with the prediction from Monte Carlo event generators for masses below 30% of the transverse momentum. The normalized cross section for groomed jets is measured with higher precision than the ungroomed cross section. Semi-analytical calculations of the jet mass beyond leading logarithmic accuracy are compared to data, as well as predictions at leading order and next-to-leading order, which include parton showering and hadronization. Overall, in the normalized cross section, the theoretical predictions agree with the measured cross sections within the uncertainties for masses from 10 to 30% of the jet transverse momentum.