Measurement of the Ratio of Branching Fractions of the Upsilon(4S) to Charged and Neutral B Mesons

TL;DR

This paper measures the ratio of charged to neutral B meson production at the Upsilon(4S) resonance using a partial reconstruction technique, providing insights into B meson decay dynamics.

Contribution

It introduces a model-independent method to determine the B meson production ratio at the Upsilon(4S) using partial reconstruction of semileptonic decays.

Findings

Measured ratio f_{+-}/f_{00} = 1.058 ± 0.084 ± 0.136

Method reduces dependence on decay models

Results consistent with equal production rates

Abstract

The ratio of charged and neutral B meson production at the Upsilon(4S), f_{+-}/f_{00}, is measured through the decays B bar -> D* l- nu_l bar, reconstructed using a partial reconstruction method where the D* is detected only through a pion daughter from the decay D* -> D pi. Using data collected by the CLEO II detector, the charged and neutral B decays are measured in such a way that their ratio is independent of decay model, limited mainly by the uncertainty in the relative efficiency for detecting neutral and charged pions. This measurement yields the ratio of production fractions times the ratio of semileptonic branching fractions, f_{+-}b_{+}/f_{00}b_0. Assuming that b_+/b_0 is equal to the lifetime ratio tau_+/tau_0 and using the world average value of tau_+/tau_0 as input, we obtain f_{+-}/f_{00}=1.058+- 0.084+- 0.136.