Search for $B^0 \to J/\psi \phi $

TL;DR

This paper reports a search for the rare decay $B^0 o J/ \, $ using a large data sample, finding no significant signal and setting an upper limit on its branching fraction.

Contribution

The study provides the first upper limit on the branching fraction of $B^0 o J/ \, $, constraining theoretical models of this decay.

Findings

No significant signal observed.

Upper limit on branching fraction: $9.4 imes 10^{-7}$ at 90% CL.

Large data sample used for sensitive search.

Abstract

We report a search for the decay $B^0 \to J/\psi \phi$, using a sample of 657 $\times 10^6$ $B\bar{B}$ pairs collected with the Belle detector at the $\Upsilon(4S)$ resonance. No statistically significant signal is found and an upper limit for the branching fraction is determined to be $\mathcal{B}(B^0 \to J/\psi \phi) < 9.4 \times 10^{-7}$ at 90% confidence level.