Measurement of Time-Dependent CP-Violating Parameters in B0 -> K0S K0S decays

TL;DR

This paper presents a measurement of CP-violating parameters in B0 -> K0S K0S decays using a large data sample from the Belle experiment, providing insights into matter-antimatter asymmetry.

Contribution

First measurement of CP-violating parameters in B0 -> K0S K0S decays with a large dataset from Belle at KEKB.

Findings

Measured S = -0.38 +0.69-0.77(stat) +-0.09(syst)

Measured A = -0.38 +-0.38(stat) +-0.05(syst)

Results are consistent with Standard Model predictions.

Abstract

We report a measurement of the CP-violating parameters in B0->K0S K0S decays based on a data sample of 657 million BBbar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. In this study, one neutral B meson is fully reconstructed in the B0->K0S K0S decay mode, and the flavor of the accompanying B meson is identified by its decay products. The CP-violating parameters are measured from the asymmetry in the distributions of the proper-time interval between the two B decays: S = -0.38 +0.69-0.77(stat) +-0.09(syst) and A = -0.38 +-0.38(stat) +-0.05(syst).