Measurement of the time-integrated CP asymmetry in $D^0\to K_S^0 K_S^0$ decays using opposite-side flavor tagging at Belle and Belle II

Sumitted to PubDB: 2025-02-10

Category: Physics / performance paper, Visibility: Latest Version Public

Authors	Michel Bertemes, Angelo Di Canto, Riccardo Manfredi
Date	2025-01-30
Working group	Charm
Belle II Number	BELLE2-PUB-PH-2025-006
Abstract	We measure the time-integrated CP asymmetry in $D^0\to K_S^0K_S^0$ decays reconstructed in $e^+e^-\to c\bar{c}$ events collected by the Belle and Belle~II experiments. The corresponding data samples have integrated luminosities of 980 and 428\invfb, respectively. To infer the flavor of the $D^0$ meson, we exploit the correlation between the flavor of the reconstructed decay and the electric charges of particles reconstructed in the rest of the $e^+e^-\to c\bar{c}$ event. This results in a sample which is independent from any other previously used at Belle or Belle~II for CP asymmetry measurements. The result, $A_{\rm CP}(D^0\to K_S^0K_S^0) = (1.3\pm 2.0\pm 0.2)\%$, where the first uncertainty is statistical and the second systematic, is consistent with previous determinations and with CP symmetry.
Journal	Phys.Rev.D
Authorship confirmation page	https://authors.belle2.org/#79
Analysis	Measurement of the time-integrated CP asymmetry in $D^0 \to K^0_S K^0_S$ decays using the charm flavor tagger