Dergi makalesi Açık Erişim

Observation of the ${\Xi }_{b}^{-}\to \psi \left(2S\right){\Xi }^{-}$ decay and studies of the ${\Xi }_{b}\left(5945{\right)}^{0}$ baryon in proton-proton collisions at $\sqrt{s}=13\text{}\text{}\mathrm{TeV}$

2024    CERN İşbirliği

The first observation of the decay ${\Xi }_{b}^{-}\to \psi \left(2S\right){\Xi }^{-}$ and measurement of the branching ratio of ${\Xi }_{b}^{-}\to \psi \left(2S\right){\Xi }^{-}$ to ${\Xi }_{b}^{-}\to J/\psi {\Xi }^{-}$ are presented. The $J/\psi $ and $\psi \left(2S\right)$ mesons are reconstructed using their dimuon decay modes. The results are based on proton-proton colliding beam data from the LHC collected by the CMS experiment at $\sqrt{s}=13\text{}\text{}\mathrm{TeV}$ in 2016–2018, corresponding to an integrated luminosity of $140\text{}\text{}{\mathrm{fb}}^{-1}$. The branching fraction ratio is measured to be $B\left({\Xi }_{b}^{-}\to \psi \left(2S\right){\Xi }^{-}\right)/B\left({\Xi }_{b}^{-}\to J/\psi {\Xi }^{-}\right)=\phantom{\rule{0ex}{0ex}}0.8{4}_{-0.19}^{+0.21}\left(\mathrm{stat}\right)±0.10\left(\mathrm{syst}\right)±0.02\left(B\right)$, where the last uncertainty comes from the uncertainties in the branching fractions of the charmonium states. New measurements of the ${\Xi }_{b}\left(5945{\right)}^{0}$ baryon mass and natural width are also presented, using the ${\Xi }_{b}^{-}{\pi }^{+}$ final state, where the ${\Xi }_{b}^{-}$ baryon is reconstructed through the decays $J/\psi {\Xi }^{-}$, $\psi \left(2S\right){\Xi }^{-}$, $J/\psi \Lambda {K}^{-}$, and $J/\psi {\Sigma }^{0}{K}^{-}$. Finally, the fraction of ${\Xi }_{b}^{-}$ baryons produced from ${\Xi }_{b}\left(5945{\right)}^{0}$ decays is determined.