Measurement of time-dependent CP violation in B 0ηK 0 decays


We present a measurement of the time-dependent CP violation parameters in B 0ηK 0 decays. The measurement is based on the full data sample containing 772 × 106 \( B\overline{B} \) pairs collected at the Υ(4S) resonance using the Belle detector at the KEKB asymmetric-energy e + e collider. The measured values of the mixing-induced and direct CP violation parameters are:

$$ \sin\ 2{\phi}_1^{\mathrm{eff}}=+0.68\pm 0.07\pm 0.03, $$
$$ {\mathcal{A}}_{{{{}_{\eta}}_{\prime}}_{K^0}}=+0.03\pm 0.05\pm 0.04, $$

where the first uncertainty is statistical and the second is systematic. The values obtained are the most accurate to date. Furthermore, these results are consistent with our previous measurements and with the world-average value of sin 2ϕ 1 measured in B 0J/ψK 0 decays.

A preprint version of the article is available at ArXiv.


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Correspondence to L. Šantelj.

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The BELLE collaboration., Šantelj, L., Yusa, Y. et al. Measurement of time-dependent CP violation in B 0ηK 0 decays. J. High Energ. Phys. 2014, 165 (2014).

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  • CP violation
  • CKM angle beta
  • e+-e- Experiments
  • B physics