Preliminary Results on |V_ub| from Inclusive Semileptonic B Decays with Neutrino Reconstruction

TL;DR

This paper measures the magnitude of |V_ub| from inclusive semileptonic B decays by reconstructing neutrinos and analyzing decay distributions, providing a detailed extraction with multiple uncertainty sources.

Contribution

It introduces a novel neutrino reconstruction method and performs a comprehensive fit to extract |V_ub| with detailed uncertainty analysis.

Findings

Measured |V_ub| as (4.05 +- 0.18 +- 0.58 +- 0.25 +- 0.21 +- 0.56) x 10^{-3}

Performed a maximum likelihood fit over full decay distribution

Quantified various sources of uncertainty in |V_ub| extraction

Abstract

We present an analysis of the composition of inclusive semileptonic B meson decays using 9.4/fb of e+ e- data taken with the CLEO detector at the Upsilon(4S) resonance. In addition to measuring the charged lepton kinematics, the neutrino 4-vector is inferred using the hermeticity of the detector. We perform a maximum likelihood fit over the full three-dimensional differential decay distribution for the fractional contributions from the B -> Xc l nu processes with Xc = D, D*, D**, and non-resonant Xc, and the process B -> Xu l nu. From the fit results we extract |V_ub|= (4.05 +- 0.18 +- 0.58 +- 0.25 +- 0.21 +-0.56) x 10^{-3} where the errors are statistical, detector systematics, B -> Xc l nu model dependence, B -> Xu l nu model dependence, and theoretical uncertainty respectively.