Time-dependent CP Asymmetries in $B^0\to K^0_S\rho^0\gamma$ Decays

TL;DR

This paper presents the first measurement of CP-violation parameters in B^0 -> K_S^0 ho^0\gamma decays, using a large data sample from the Belle detector, providing insights into CP violation in radiative B decays.

Contribution

It reports the first measurement of time-dependent CP asymmetries in B^0 -> K_S^0 ho^0\gamma decays, using 657 million Bar B pairs, and provides the measured CP-violation parameters.

Findings

Measured S_{K_S^0 ho^0\gamma} = 0.11 ± 0.33 (stat.) ± 0.05-0.09 (syst.)

Measured A_eff = 0.05 ± 0.18 (stat.) ± 0.06 (syst.) for specified mass ranges

First experimental constraints on CP violation in this decay mode.

Abstract

We report the first measurement of CP-violation parameters in B^0 -> K_S^0\rho^0\gamma decays based on 657 million B\bar B pairs collected with the Belle detector at the KEKB asymmetric-energy collider. We measure the time-dependent CP violating parameter S_{K_S^0\rho^0\gamma}= 0.11 +/- 0.33(stat.)^{+0.05}_{-0.09}(syst.). We also obtain the effective direct CP violating parameter A_eff=0.05 +/- 0.18(stat.) +/- 0.06(syst.) for m_{K_S\pi^+\pi^-}<1.8 GeV/c^2 and 0.6 GeV/c^2<m_{\pi^+\pi^-}<0.9 GeV/c^2.