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arXiv · 2609.01000

NNLL fit of the transverse-momentum-dependent distribution of unpolarised gluons to LHCb data on $J/\psi$-pair production

D. Boer·J. Bor·A. C. Serri·M. G. Echevarria·J. P. Lansberg·S. F. Romera·P. Taels
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Abstract

We perform the first fit of the unpolarised gluon transverse-momentum-dependent distribution $f_1^g$ up to next-to-next-to-leading-logarithmic accuracy to the double-differential distribution in the invariant mass and transverse momentum of the latest $J/\psi$-pair production LHCb data. We review previous attempts to describe the older $J/\psi$-pair LHCb data using $f_1^g$, and discuss two novel methodologies which allow us to account in the fit for both the perturbative and PDF uncertainties to construct $f_1^g$ in the perturbative region. It turns out that the consideration of these uncertainties is crucial for a meaningful fit to such low-scale gluon-sensitive data.

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D. Boer, J. Bor, A. C. Serri, M. G. Echevarria, J. P. Lansberg, S. F. Romera, P. Taels. 2026-09-01. NNLL fit of the transverse-momentum-dependent distribution of unpolarised gluons to LHCb data on $J/\psi$-pair production. https://arxiv.org/abs/2609.01000

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