Measurement of the time-integrated CP asymmetry in $D^0\to K_S^0{K}_S^0$ decays using Belle and Belle II data

Abstract

We measure the time-integrated CP asymmetry in $D^0\to K_S^0{K}_S^0$ decays reconstructed in $e^{+}{e}^{-}\to c\overline{c}$ events collected by the Belle and Belle II experiments. The corresponding data samples have integrated luminosities of 980 fb${}^{-1}$ and 428 fb${}^{-1}$, respectively. The $D^0$ decays are required to originate from the $D^{\ast +}\to D^0\ddot{I}{€}^{+}$ decay, which determines the charm flavor at production time. A control sample of $D^0\to K^{+}{K}^{-}$ decays is used to correct for production and detection asymmetries. The result, $(-1.4\pm 1.3(\mathrm{stat})\pm 0.1(\mathrm{syst}))\%$, is consistent with previous determinations and with CP symmetry.

10 pages, 3 figures. arXiv admin note: text overlap with arXiv:2410.22961