Measurement of time-dependent CP violation parameters in $B^0 \to K_0^SK_0^SK_0^S$ decays at Belle

TL;DR

This study measures time-dependent CP violation in B0 decays to three neutral kaons using a large data sample, finding results consistent with the Standard Model and indicating a 2.5 sigma significance of CP violation.

Contribution

First measurement of time-dependent CP violation parameters in B0 to K0_S K0_S K0_S decays using Belle data.

Findings

Mixing-induced CP asymmetry: -0.71 ± 0.23 (stat) ± 0.05 (syst)

Direct CP asymmetry: 0.12 ± 0.16 (stat) ± 0.05 (syst)

CP violation significance: 2.5 standard deviations

Abstract

We measure the time-dependent $C\!P$ violation parameters in $B^{0} \to K^{0}_{S}K^{0}_{S}K^{0}_{S}$ decays using $772 \times 10^6$ $B {\mkern 1.5mu\overline{\mkern-1.5mu B \mkern-0.1mu}\mkern 0.1mu}$ pairs collected at the $\Upsilon (4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The obtained mixing-induced and direct $C\!P$ asymmetries are $-0.71 \pm 0.23~{\rm(stat)} \pm 0.05~{\rm(syst)}$ and $0.12 \pm 0.16~{\rm(stat)} \pm 0.05~{\rm(syst)}$, respectively. These values are consistent with the Standard Model predictions. The significance of $C\!P$ violation differs from zero by 2.5 standard deviations.