Observation of $B\to \phi K$ and $B\to \phi K^{*}$

TL;DR

This study reports the observation of specific charmless hadronic B meson decays into phi K and phi K* final states, measuring their branching fractions with data from the CLEO II detector, and setting upper limits for less significant modes.

Contribution

First observation of B -> phi K and B -> phi K* decays with measured branching fractions, advancing understanding of charmless B meson decay processes.

Findings

Observed B- -> phi K- decay with branching fraction ~5.5 x 10^{-6}

Observed B0 -> phi K*0 decay with branching fraction ~11.5 x 10^{-6}

Set upper limits for B0 -> phi K0 and B- -> phi K*- decays

Abstract

We have studied two-body charmless hadronic decays of $B$ mesons into the final states phi K and phi K^*. Using 9.7 million $B\bar{B}$ pairs collected with the CLEO II detector, we observe the decays B- -> phi K- and B0 -> phi K*0 with the following branching fractions: BR(B- -> phi K-)=(5.5 +2.1-1.8 +- 0.6) x 10^{-6} and BR(B0 -> phi K*0)=(11.5 +4.5-3.7 +1.8-1.7) x 10^{-6}. We also see evidence for the decays B0 -> phi K0 and B- -> phi K*-. However, since the statistical significance is not overwhelming for these modes we determine upper limits of <12.3 x 10^{-6} and <22.5 x 10^{-6} (90% C.L.) respectively.