Search for $K_{\mathrm{S}(\mathrm{L})}^0\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ decays at LHCb

Abstract

A search for $K_{\mathrm{S}(\mathrm{L})}^0\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ decays is performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of $13\mathrm{TeV}$, corresponding to an integrated luminosity of $5.4\mathrm{f}{\mathrm{b}}^{-1}$. No $K_{\mathrm{S}(\mathrm{L})}^0\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-}$ signals are found and upper limits are set for the first time on the branching fractions $\mathcal{B}(K_{\text{S}}^0\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-})<1.4\times 10^{-9}$ and $\mathcal{B}(K_{\text{L}}^0\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\hat{I}{¼}^{+}\hat{I}{¼}^{-})<6.6\times 10^{-7}$, at the 90% confidence level.

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/3935/ (LHCb public pages)