Search for B -> phi pi decays

TL;DR

This study searches for rare B meson decays into phi and pion states, using a large data sample, but finds no evidence and sets upper limits on their branching fractions.

Contribution

First search for B -> phi pi decays using Belle data, establishing upper limits on their branching fractions.

Findings

No significant signal observed.

Upper limits set at 3.3 x 10^-7 and 1.5 x 10^-7.

Results constrain new physics models.

Abstract

We report on a search for the charmless decays $B^{+} \to\phi\pi^{+}$ and $B^{0} \to\phi \pi^{0}$ that are strongly suppressed in the Standard Model. The analysis is based on a data sample of $657 \times 10^6$ $B \bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We find no significant signal and set upper limits of $3.3 \times 10^{-7}$ for $B^{+} \to \phi \pi^{+}$ and $1.5 \times 10^{-7}$ for $B^0 \to \phi \pi^0$ at the 90% confidence level.