Measurement of the $B^0\to \ddot{I}(770{)}^0{\hat{I}}^3$ branching fraction

Abstract

The ratio between the branching fractions of the $B^0\to \ddot{I}(770{)}^0{\hat{I}}^3$ and $B^0\to K^{\ast }(892{)}^0{\hat{I}}^3$ decays is measured with proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb${}^{-1}$. The measured value is \begin{equation*} \frac{{\cal B}(B^0\rightarrow ρ(770)^{0}γ)}{{\cal B}(B^0\rightarrow K^{*}(892)^{0}γ)}=0.0189\pm 0.0007\pm 0.0005, \end{equation*} where the first uncertainty is statistical and the second systematic. The branching fraction for $B^0\to \ddot{I}(770{)}^0{\hat{I}}^3$ decays is hence obtained as \begin{equation*} {\cal{B}}(B^0\rightarrow ρ(770)^{0}γ) =(7.9\pm 0.3\pm 0.2\pm 0.2) \times 10^{-7}, \end{equation*} where the last uncertainty is due to the branching fraction of the normalisation mode. This result assumes that both the $\ddot{I}(770{)}^0$ and $K^{\ast }(892{)}^0$ decays saturate the dihadron mass spectra considered in the analysis. It is consistent with the current world-average value and by far the most precise measurement to date.

All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://lbfence.cern.ch/alcm/public/analysis/full-details/4057/ (LHCb public pages)