Determination of |Vub| in the BaBar experiment using the lepton invariant mass squared 
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D. Fortin, University of Victoria

A measurement of the CKM matrix element |Vub| is performed using
charmless semileptonic B decays from a sample of 88 million events
recorded with the BaBar detector.  Decays are primarily identified by
the presence of a high momentum electron and a neutrino inferred from
the missing momentum.  Further selection requirements are made on the
electron energy and the invariant mass squared of the
neutrino-electron pair to suppress the dominant background from
semileptonic B decays to charm. Signal efficiency and background
estimates derived from Monte Carlo simulations are adjusted using a
control sample in the data and then used to measure a partial
branching fraction for B --> Xu en.  Combining this measurement with
the B lifetime and using theoretical input allows for the
determination of the CKM matrix element |Vub|.