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arXiv · 2512.17408

The Lund $b$-jet plane

Andrea Ghira·Simone Marzani·Gregory Soyez
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Abstract

We compute the primary Lund plane density for jets initiated by a massive ($b$) quark to single logarithmic accuracy in Quantum Chromodynamics (QCD). In order to capture mass effects, we consider quasi-collinear factorisation 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, keeping the full dependence on the $b$-quark mass. While our all-order results can be applied to both hadron and lepton colliders, we present, as first phenomenological application, the resummed calculation of the Lund plane density in $e^+e^-$ collisions at $\sqrt{s}=M_Z$, matched to tree-level matrix elements.

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Andrea Ghira, Simone Marzani, Gregory Soyez. 2025-12-19. The Lund $b$-jet plane. https://arxiv.org/abs/2512.17408

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