Measurement of $CP$ violation observables in $D^{+}\to K^{-}{K}^{+}\ddot{I}{€}^{+}$ decays

Abstract

A search for violation of the charge-parity $CP$ symmetry in the $D^{+}\to K^{-}{K}^{+}\ddot{I}{€}^{+}$ decay is presented, with proton-proton collision data corresponding to an integrated luminosity of 5.4 fb${}^{-1}$, collected at a center-of-mass energy of $13$ TeV with the LHCb detector. A novel model-independent technique is used to compare the $D^{+}$ and $D^{-}$ phase-space distributions, with instrumental asymmetries subtracted using the $D_s^{+}\to K^{-}{K}^{+}\ddot{I}{€}^{+}$ decay as a control channel. The $p$-value for the hypothesis of $CP$ conservation is $8.1\%$. The $CP$ asymmetry observables $A_{CP|S}^{\ddot{I}•\ddot{I}{€}^{+}}=(0.95\pm 0.43_{stat}\pm 0.26_{syst})\times 10^{-3}$ and $A_{CP|S}^{{\overline{K}}^{\ast 0}{K}^{+}}=(-0.26\pm 0.56_{stat}\pm 0.18_{syst})\times 10^{-3}$ are also measured. These results show no evidence of $CP$ violation and represent the most sensitive search performed through the phase space of a multibody decay.

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/1616 (LHCb public pages)