Girth and groomed radius of jets recoiling against isolated photons in lead-lead and proton-proton collisions at √𝑠NN = 5.02 TeV

Belyaev, A.; Boos, E.E.; Demiyanov, A.; Ershov, A.A.; A, G.; Khein, L.; Kodolova, O.L.; Korotkikh, V.L.; Obraztsov, S.V.; Petrushanko, S.V.; Savrin, V.I.; Snigirev, A.M.; Vardanyan, I.; CMS, C.

Авторы: Belyaev Andrey, Boos E.E., Demiyanov A., Ershov A.A., A Gribushin, Khein L., Kodolova O.L., Korotkikh V.L., Obraztsov S.V., Petrushanko S.V., Savrin V.I., Snigirev A.M., Vardanyan I., CMS Collaboration
Журнал: Physics Letters B
Том: 861
Год издания: 2025
Издательство: Elsevier BV
Местоположение издательства: Netherlands
Номер статьи: 139088
DOI: 10.1016/j.physletb.2024.139088
Аннотация: This Letter presents the first measurements of the groomed jet radius 𝑅g and the jet girth 𝑔 in events with an isolated photon recoiling against a jet in lead-lead (PbPb) and proton-proton (pp) collisions at the LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The observables 𝑅g and 𝑔 provide a quantitative measure of how narrow or broad a jet is. The analysis uses PbPb and pp data samples with integrated luminosities of 1.7 nb−1 and 301 pb−1, respectively, collected with the CMS experiment in 2018 and 2017. Events are required to have a photon with transverse momentum 𝑝γT > 100 GeV and at least one jet back-to-back in azimuth with respect to the photon and with transverse momentum 𝑝jetT such that 𝑝jet T ∕𝑝γ T > 0.4. The measured 𝑅g and 𝑔 distributions are unfolded to the particle level, which facilitates the comparison between the PbPb and pp results and with theoretical predictions. It is found that jets with 𝑝jet T ∕𝑝γ T > 0.8, i.e., those that closely balance the photon 𝑝γT, are narrower in PbPb than in pp collisions. Relaxing the selection to include jets with 𝑝jet T ∕𝑝γ T > 0.4 reduces the narrowing of the angular structure of jets in PbPb relative to the pp reference. This shows that selection bias effects associated with jet energy loss play an important role in the interpretation of jet substructure measurements.
Добавил в систему: Петрушанко Сергей Владимирович

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Girth and groomed radius of jets recoiling against isolated photons in lead-lead and proton-proton collisions at √𝑠NN = 5.02 TeVстатья Исследовательская статья

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