CMS-PAS-HIN-24-007

CMS-PAS-HIN-24-007
Exploring small-angle emissions in prompt D$ ^0 $ jets in proton-proton collisions at $ \sqrt{s} = $ 5.02 TeV
CMS Collaboration
6 August 2024

Abstract: This note presents a measurement of the angular structure of jets containing a prompt D$ ^0 $ meson and of inclusive jets in proton-proton (pp) collisions at the LHC at a center-of-mass energy of 5.02 TeV. The measurement uses collision data collected by the CMS experiment in 2017, corresponding to an integrated luminosity of 301 pb$ ^{-1} $. Two jet grooming algorithms, late-$ k_\mathrm{T} $ and soft drop, are used to study the intrajet radiation pattern of these jets using the iterative Cambridge-Aachen declustering. The late-$ k_\mathrm{T} $ algorithm selects hard collinear emissions, such that the sensitivity to the charm quark mass is enhanced with strong resilience to soft- and wide-angle radiation and to gluon splitting to charm quark-antiquark pairs. In contrast to the late-$ k_\mathrm{T} $ algorithm, the soft-drop grooming algorithm tends to select emissions at larger angles, with reduced sensitivity to the charm quark mass and enhanced contributions from gluon splitting to charm quark-antiquark pairs. The splitting angle distributions obtained with these two algorithms show that there is a shift of the distribution of prompt D$ ^0 $ jets with respect to inclusive jets for jet transverse momentum of 100 $ < p_\mathrm{T}^\text{jet} < $ 120 GeV. The shift observed in late-$ k_\mathrm{T} $ is consistent with the dead cone effect, whereas the shift for splittings selected with soft drop appears to be dominated by gluon splitting to charm quark-antiquark effects. The measured distributions are corrected to the particle level and set constraints on the substructure of high-$ p_\mathrm{T} $ charm quark jets.
Links: CDS record (PDF) ; CADI line (restricted) ; These preliminary results are superseded in this paper, Submitted to JHEP. The superseded preliminary plots can be found here.

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