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Collider Cross Talk
Dead-cone effect in b-jets [LHCb, TH]
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Europe/Zurich
4/2-011 - TH common room (CERN)
Description
Abstract
LHCb has measured the Lund jet plane for light-quark-enriched and beauty-quark jets, using pp collision data at $\sqrt{s} = 13$ TeV corresponding to 5.4 fb$^{-1}$ collected during Run 2 [Phys. Rev. D 12, 072015 (2025)]. Light-quark-enriched jets are selected recoiling against a Z boson in the forward region, while beauty jets are built around fully reconstructed $B^{\pm}$ mesons. Declustering the jets with the Cambridge/Aachen algorithm maps each emission by its angle and momentum. This reveals a strong suppression of collinear radiation in beauty jets relative to light-quark jets, constituting the first direct observation of the dead-cone effect in beauty-quark jets.
In this talk, we will present the calculation for the Lund -b jet plane observable to single logarithmic accuracy. In order to capture mass effects, we consider quasi-collinear factorization of QCD amplitudes and we include contributions from the running of the QCD coupling and from collinear evolution, in a variable flavour-number scheme.
Furthermore, the resummation of soft logarithms, including clustering effects, is performed numerically. Finally, we will present the full resummed calculation matched to tree-level matrix elements of the Lund plane density in e+e- collisions.
Speakers
Manuel Ramírez García
Manuel Ramírez García is a PhD student at the University of Michigan and a member of the LHCb collaboration, based at CERN. His research focuses on heavy-flavour jet physics, and he is involved in the Upstream Tracker, one of the LHCb tracking subdetectors.
Andrea Ghira
Andrea Ghira is a postdoc researcher at the Technical University of Munich (TUM), where he works in the group of Lorenzo Tancredi. He obtained his PhD from the University of Genoa, under the supervision of Professors Simone Marzani and Giovanni Ridolfi. His research focuses on heavy-flavour physics, jet substructure, and scattering amplitude calculations.