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

Abstract

We measure the time-integrated $CP$ asymmetry, $A_{CP}$, in $D^0\to {\pi }^0{\pi }^0$ decays reconstructed in $e^{+}{e}^{-}\to c\bar{c}$ events collected by Belle II during 2019--2022. The data corresponds to an integrated luminosity of 428${\mathrm{fb}}^{-1}$. The $D^0$ decays are required to originate from the flavor-conserving $D^{\ast +}\to D^0{\pi }^{+}$ decay to determine the charm flavor at production time. Control samples of $D^0\to K^{-}{\pi }^{+}$ decays, with or without an associated pion from a $D^{\ast +}$ decay, are used to correct for detection asymmetries. The result, $A_{CP}(D^0\to {\pi }^0{\pi }^0)=(0.30\pm 0.72\pm 0.20)\%$, where the first uncertainty is statistical and the second systematic, is consistent with $CP$ symmetry.

References in corpus (17)

• An Introduction to PYTHIA 8.2
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Observation of $CP$ violation in charm decays
• New Physics and CP Violation in Singly Cabibbo Suppressed D Decays
• Charm Meson Decays
• Revisiting CP violation in $D\to PP$ and $VP$ decays
• Reweighting with Boosted Decision Trees
• Implications of the LHCb discovery of CP violation in charm decays
• Measurement of the time-integrated $CP$ asymmetry in $D^0\to K^{-}{K}^{+}$ decays
• Final-state interactions in the CP asymmetries of charm-meson two-body decays
• Search for time-dependent $CP$ violation in $D^0\to K^{+}{K}^{-}$ and $D^0\to {\pi }^{+}{\pi }^{-}$ decays
• A $U$-Spin Anomaly in Charm CP Violation
• Search for CP violation in D^0 -> pi^0 pi^0 decays
• Enhanced charm CP asymmetries from final state interactions
• Simple model for large CP violation in charm decays, B-physics anomalies, muon g-2, and Dark Matter
• CsI(Tl) Pulse Shape Discrimination with the Belle II Electromagnetic Calorimeter as a Novel Method to Improve Particle Identification at Electron-Positron Colliders
• Evidence of $A_{CP}(D^0\to {\pi }^{+}{\pi }^{-})$ implies observable $CP$ violation in the $D^0\to {\pi }^0{\pi }^0$ decay

Cited by in corpus (1)

• Implications of the evidence for direct $\mathbf{CP}$ violation in $D\to {\pi }^{+}{\pi }^{-}$ decays