Experimental Limits on Weak Annihilation Contributions to b -->u ell nu Decay

Abstract

We present the first experimental limits on high-q^2 contributions to charmless semileptonic B decays of the form expected from the Weak Annihilation (WA) decay mechanism. Such contributions could bias determinations of |Vub| from inclusive measurements of B-> X_u lnu. Using a wide range of models based on available theoretical input we set a limit of (Gamma_WA/Gamma_b->u) < 7.4% (90% confidence level) on the WA fraction, and assess the impact on previous inclusive determinations of |Vub|.

arXiv comment8 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2005/, Submitted to PRL

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• Measurements of Partial Branching Fractions of Inclusive $B\to X_u{\ell }^{+}{\nu }_{\ell }$ Decays with Hadronic Tagging
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• B Meson Decays
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• The continuum and interference effect in $e^{+}{e}^{-}\to D^0{\bar{D}}^0,D^{+}{D}^{-}$ processes
• Precision Determination of $|V_{ub}|$
• Isospin in $B$ Decays and the $(B^0{\bar{B}}^0)/(B^{+}{B}^{-})$ Production Ratio
• Measurement of the Ratio of Partial Branching Fractions of Inclusive $\overline{B}\to X_u\ell \overline{\nu }$ to $\overline{B}\to X_c\ell \overline{\nu }$ and the Ratio of their Spectra with Hadronic Tagging
• Study of $B^{+}\to {\mu }^{+}{\nu }_{\mu }$ decays at Belle and Belle II
• Status of |Vub|, |Vcb| and their relative phase