Exploring small-angle emissions in charm quark jets in proton-proton collisions at $\sqrt{s}$ = 5.02 TeV

TL;DR

This study investigates the internal structure of charm quark jets in proton-proton collisions at 5.02 TeV, revealing effects consistent with the dead-cone phenomenon and gluon splitting, providing data to refine jet substructure models.

Contribution

First measurement of the angular structure of charm-containing jets at 5.02 TeV using advanced grooming algorithms, highlighting effects of charm quark mass on jet radiation patterns.

Findings

Shift in splitting-angle distribution for charm jets supports dead-cone effect.

Gluon splitting to charm quark pairs influences jet substructure.

Results can constrain theoretical models of charm jet formation.

Abstract

A measurement of the angular structure of jets containing a prompt D$^0$ meson and of inclusive jets in proton-proton collisions at the LHC at a center-of-mass energy of 5.02 TeV is presented. The data corresponding to an integrated luminosity of 301 pb$^{-1}$ were collected by the CMS experiment in 2017. Two jet grooming algorithms, late-$k_\mathrm{T}$ and soft drop, are used to study the intrajet radiation pattern using iterative Cambridge$-$Aachen declustering. The splitting-angle distributions of jets with transverse momentum ($p_\mathrm{T}$) of around 100 GeV, obtained with these two algorithms, show that there is a shift of the distribution for jets containing a prompt D$^0$ meson with respect to inclusive jets. The shift observed in the late-$k_\mathrm{T}$ grooming approach is consistent with the dead-cone effect, whereas the shift for splittings selected with the soft-drop algorithm appears to be dominated by gluon splitting to charm quark-antiquark pairs. The measured distributions are corrected to the particle level and can be used to constrain model predictions for the substructure of high-$p_\mathrm{T}$ charm quark jets.