Observation of the $B_c^{+}\to J/\psi {\pi }^{+}{\pi }^0$ decay

Abstract

The first observation of the $B_c^{+}\to J/\psi {\pi }^{+}{\pi }^0$ decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of 9fb${}^{-1}$, collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV. The ratio of its branching fraction relative to the $B_c^{+}\to J/\psi {\pi }^{+}$ channel is measured to be $$\frac{\mathcal{B}(B_c^{+}\to J/\psi {\pi }^{+}{\pi }^0)}{\mathcal{B}(B_c^{+}\to J/\psi {\pi }^{+})}=2.80\pm 0.15\pm 0.11\pm 0.16,$$ where the first uncertainty is statistical, the second systematic and the third related to imprecise knowledge of the branching fractions for $B^{+}\to J/\psi K^{\ast +}$ and $B^{+}\to J/\psi K^{+}$ decays, which are used to determine the ${\pi }^0$ detection efficiency. The ${\pi }^{+}{\pi }^0$ mass spectrum is found to be consistent with the dominance of an intermediate ${\rho }^{+}$ contribution in accordance with a model based on QCD factorisation.

30 pages, 6 figures. All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-046.html (LHCb public pages)

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Cited by in corpus (3)

• Observation of orbitally excited $B_c^{+}$ states
• Study of $B_c(1P{)}^{+}$ states in the $B_c^{+}\gamma$ mass spectrum
• Search for $B_{(s)}^{\ast 0}\to {\mu }^{+}{\mu }^{-}$ in $B_c^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$ decays