Measurement of the CP-Violating Asymmetries in B0 -> KS pi0 and of the Branching Fraction of B0 -> K0 pi0

TL;DR

This paper reports measurements of CP-violating asymmetries and the branching fraction for B0 decays to K0 pi0 using data from the BaBar experiment, providing insights into CP violation in the B meson system.

Contribution

First measurement of time-dependent CP asymmetries and branching fraction for B0 -> K0 pi0 decays using BaBar data.

Findings

Measured direct CP asymmetry C_{K^0_S pi^0} = 0.24 ± 0.15 ± 0.03

Measured mixing-induced CP asymmetry S_{K^0_S pi^0} = 0.40 ± 0.23 ± 0.03

Branching fraction B(B0 -> K0 pi0) = (10.3 ± 0.7 ± 0.6) x 10^{-6}

Abstract

We present a measurement of the time-dependent CP-violating asymmetries in $B^0 \to K^0_{\scriptscriptstyle S}\pi^0$ decays based on 383 million $\Upsilon(4S)\to B\kern 0.18em\bar{\kern -0.18em B}$ events collected by the \mbox{\slshape B\kern-0.1em{\smaller A}\kern-0.1em B\kern-0.1em{\smaller A\kern-0.2em R}} experiment at the PEP-II asymmetric-energy $B$ Factory at SLAC. We measure the direct CP-violating asymmetry $C_{K^0_{\scriptscriptstyle S}\pi^0} = 0.24 \pm 0.15 \pm 0.03$ and the CP-violating asymmetry in the interference between mixing and decay $S_{K^0_{\scriptscriptstyle S}\pi^0} = 0.40 \pm 0.23 \pm 0.03$, where the first errors are statistical and the second are systematic. On the same sample, we measure the decay branching fraction, obtaining ${\cal B}(B^0 \to K^0\pi^0)= (10.3 \pm 0.7 \pm 0.6)\times 10^{-6}$.