Measurement of the decays B-->phi K and B-->phi K^*

TL;DR

This paper reports the first observation and measurement of branching fractions for B meson decays into phi K and phi K* final states, providing important data for understanding rare B decays and testing the Standard Model.

Contribution

First observation and precise measurement of B-->phi K and B-->phi K* decay branching fractions using a large B meson sample.

Findings

Measured branching fractions for B-->phi K and B-->phi K* decays.

Established an upper limit for B-->phi pi+ decay.

Data consistent with Standard Model predictions.

Abstract

We have observed the decays B-->phi K and phi K^* in a sample of over 45 million B mesons collected with the BABAR detector at the PEP-II collider. The measured branching fractions are BF(B^+ --> phi K^+) = (7.7^{+1.6}_{-1.4}+/- 0.8) x 10^{-6}, BF(B^0 --> phi K^0) = (8.1^{+3.1}_{-2.5}+/- 0.8) x 10^{-6}, BF(B^+ --> phi K^{*+}) = (9.7^{+4.2}_{-3.4}+/- 1.7) x 10^{-6}, and BF(B^0 --> phi K^{*0}) = (8.6^{+2.8}_{-2.4}+/- 1.1) x 10^{-6}. We also report the upper limit BF(B^+ --> phi pi^+) < 1.4 x 10^{-6}$ (90% CL).