Determinations of |Vub| from Inclusive Semileptonic B Decays with Reduced Model Dependence

TL;DR

This paper presents two new methods to measure the CKM matrix element |Vub| from inclusive semileptonic B decays, reducing model dependence by combining hadronic mass distributions with photon energy spectra and full phase space measurements.

Contribution

The study introduces two novel approaches for determining |Vub| with reduced model dependence using hadronic mass and photon energy spectra in semileptonic B decays.

Findings

|Vub| from partial rate: (4.43 +- 0.38 (stat) +- 0.25 (syst) +- 0.29 (theo)) x 10^-3

|Vub| from full rate: (3.84 +- 0.70 (stat) +- 0.30 (syst) +- 0.10 (theo)) x 10^-3

Reduced model dependence in |Vub| measurements.

Abstract

We report two novel determinations of |Vub| with reduced model dependence, based on measurements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson from Y(4S) to BBbar events. In one approach, we combine the inclusive B to X_u l nu rate, integrated up to a maximum hadronic mass m_X < 1.67GeV, with a measurement of the inclusive B to X_s gamma photon energy spectrum. We obtain |Vub| = (4.43 +- 0.38stat +- 0.25syst +- 0.29theo)*10^-3. In another approach we measure the total B to X_u l nu rate over the full phase space and find |Vub| = (3.84 +- 0.70stat +- 0.30syst +- 0.10theo)*10^-3.