Measurement of Hadronic Recoil Mass Moments in Semileptonic B Decay

TL;DR

This paper reports a preliminary measurement of the hadronic recoil mass moments in inclusive semileptonic B meson decays, using a large dataset and a detailed three-dimensional fit to infer decay contributions and extract mass moments.

Contribution

It introduces a novel measurement of the recoil mass moments in B decays using a comprehensive fit to the decay distribution and neutrino inference, enhancing understanding of B decay dynamics.

Findings

Measured <M_X2 - M_D^2> at two lepton energy thresholds.

Quantified uncertainties from statistics, systematics, and models.

Provided results consistent with theoretical expectations.

Abstract

We present a preliminary measurement of the composition of inclusive semileptonic B meson decays using 9.4 fb^{-1} of e^+e^- data taken with the CLEO detector at the Upsilon(4S) resonance. In addition to measuring the charged lepton kinematics, the neutrino four-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->X_c l nu processes with X_c = D, D^*, D^**, and non-resonant X_c, and the process B -> X_u l nu. From the fit results we extract <M_X2 - M_D[Bar]^2> = (0.456 +- 0.014 +- 0.045 +- 0.109) GeV^2/c^4 with minimum lepton energy of 1.0 GeV and <M_X2 - M_D[Bar]^2> (0.293 +- 0.012 +- 0.033 +- 0.048) GeV^2/c^4 with minimum lepton energy of 1.5 GeV. The uncertainties are from statistics, detector systematic effects, and model dependence, respectively.