Study of Exclusive Semileptonic B Meson Decays toTau Leptons

[摘要] We present the results of a search for four exclusive semileptonic decays B {yields} D{sup (*)}{tau}{sup -}{bar {nu}}{sub {tau}} in 209 fb{sup -1} of data collected with the BABAR detector, corresponding to 232 million e+e- {yields} {Upsilon}(4S) {yields} B{bar B} events. We select events with a D{sup (*)} meson and a light lepton (e or {mu}) recoiling against a fully-reconstructed B meson. We perform a fit to the lepton spectrum and missing mass squared to discriminate signal events from backgrounds, predominantly B {yields} D{sup (*)}{tau}{sup -}{bar {nu}}{sub {tau}}. A control sample of identified D**{ell}{sup -}{bar {nu}}{sub {ell}} events is included in the fit to estimate the background contribution from these decays. We measure {beta}(B {yields} D{sub {tau}{nu}}) = (0.86{+-}0.24{+-}0.11{+-}0.06)% and {beta}(B {yields} D*{sub {tau}{nu}}) = (1.62{+-}0.31{+-}0.10{+-}0.05)%, where the errors are statistical, systematic, and normalization-mode related, respectively, and where the results are expressed for the {bar B}{sup 0} lifetime.

[发布日期] 2007-10-15

[学科分类] 物理（综合）

[关键词] B MESONS;LEPTONS;LIFETIME;MESONS;MISSING MASS;SEMILEPTONIC DECAY;TAU PARTICLES Experiment-HEP;HEPEX