Measurement of the $CP$ asymmetry in $D^0\to {\pi }^{+}{\pi }^{-}{\pi }^0$ decays at Belle II

Abstract

We measure the time- and phase-space-integrated $CP$ asymmetry $A_{CP}$ in $D^0\to {\pi }^{+}{\pi }^{-}{\pi }^0$ decays reconstructed in $e^{+}{e}^{-}\to c\bar{c}$ events collected by the Belle II experiment from 2019 to 2022. This sample corresponds to an integrated luminosity of 428 fb${}^{-1}$. We require $D^0$ mesons to be produced in $D^{\ast +}\to D^0{\pi }^{+}$ decays to determine their flavor at production. Control samples of $D^0\to K^{-}{\pi }^{+}$ decays are used to correct for reconstruction-induced asymmetries. The result, $A_{CP}(D^0\to {\pi }^{+}{\pi }^{-}{\pi }^0)=(0.29\pm 0.27\pm 0.13)\%$, where the first uncertainty is statistical and the second systematic, is the most precise result to date and is consistent with $CP$ conservation.

13 pages, 7 figures. Published on Physical Review D

References in corpus (7)

• An Introduction to PYTHIA 8.2
• Observation of $CP$ violation in charm decays
• New Physics and CP Violation in Singly Cabibbo Suppressed D Decays
• The Design, Construction, Operation and Performance of the Belle II Silicon Vertex Detector
• Measurement of the time-integrated $CP$ asymmetry in $D^0\to K^{-}{K}^{+}$ decays
• Search for $CP$ violation in the phase space of $D^0\to {\pi }^{-}{\pi }^{+}{\pi }^0$ decays with the energy test
• Search for time-dependent $CP$ violation in $D^0\to {\pi }^{+}{\pi }^{-}{\pi }^0$ decays