Speaker
Michael Ziegler
(EKP)
Description
In the Standard Model the decay $B^0 \to \tau^+ \tau^-$ is highly suppressed with a predicted branching ratio of $\mathcal{B}_{\rm{SM}}(B^0 \to \tau^+ \tau^-) \approx 3 \times 10^{-8}$. The BaBar collaboration estimated an upper limit of $\mathcal{B}< 4.1 \times 10^{-3}$ at the 90\% confidence level using a data sample of $232 \times 10^6$ $B\bar B$ pairs.
The search presented in this talk is performed on data collected on the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The data sample contains $772 \times 10^6$ $B\bar B$ pairs, which is a factor three more than used in the BaBar analysis.
For the analysis one of the $B$ mesons is fully reconstructed in hadronic decay modes using a hierarchical NeuroBayes-based algorithm. Using a multivariate analysis method the background is reduced to reach higher sensitivity.
An expected upper limit on the branching ratio is estimated on simulated Monte Carlo events.
Primary author
Michael Ziegler
(EKP)
