Journal Article

B ¯ s , d 0 B̅_(s,d)⁰ → J/ψμ + μ − decays in QCD factorization

Chun-Yang Zhao, Yan Shi, Xing-Bo Yuan, Ya-Dong Yang, Xin-Qiang Li

2026

Overview

Abstract Motivated by the first LHCb searches for the rare B ¯ s , d 0$$ {\\overline{B}}_{s,d}^0 $$→ J/ψμ + μ − decays, we perform a detailed study of these processes within the QCD factorization formalism. Since the transverse size of the J/ψ meson is small in the heavy quark mass limit, this formalism is generally expected to hold for these decays. We include both the leading- and next-to-leading-order QCD corrections to the hard-scattering kernels, which are convoluted with the light-cone distribution amplitudes (LCDAs) of the initial- and final-state hadrons. It is numerically found that, depending on the model parameters for the leading-twist B-meson LCDA, the maximum branching ratios of B ¯ s 0$$ {\\overline{B}}_s^0 $$→ J/ψμ + μ − and B ¯ d 0$$ {\\overline{B}}_d^0 $$→ J/ψμ + μ −, integrated over the dimuon invariant mass squared q 2 from 1 GeV2 to ( m B s , d$$ {m}_{B_{s,d}} $$− m J/ψ )2, can reach up to 2.21 × 10−9 and 7.69 × 10−11 at the leading order in α s , respectively. After incorporating the non-factorizable one-loop vertex corrections, these branching ratios are further reduced by about one order of magnitude, with B B ¯ s 0 → J / ψ μ + μ − q 2 ≥ 1 GeV 2$$ \\mathcal{B}{\\left.\\left({\\overline{B}}_s^0\\to J/\\psi {\\mu}^{+}{\\mu}^{-}\\right)\\right|}_{q^2\\ge 1{\\textrm{GeV}}^2} $$= 2.88 × 10−10 and B B ¯ d 0 → J / ψ μ + μ − q 2 ≥ 1 GeV 2$$ \\mathcal{B}{\\left.\\left({\\overline{B}}_d^0\\to J/\\psi {\\mu}^{+}{\\mu}^{-}\\right)\\right|}_{q^2\\ge 1{\\textrm{GeV}}^2} $$= 1.07 × 10−11. In addition, we have presented the dimuon invariant mass distributions of the individual and total helicity amplitudes squared, as well as the differential and integrated longitudinal polarization fractions of the J/ψ meson, which could be probed by the future LHCb and Belle II experiments with more accumulated data.

• Publisher: SpringerOpen
• Subject: Bottom Quarks / Rare Decays