Measurement of the semileptonic decays B{yields}D{tau}{sup -}{nu}{sub {tau}} and B{yields}D*{tau}{sup -}{nu}{sub {tau}}

Journal Article · Fri May 01 00:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.79.092002· OSTI ID:21308391

Aubert, B; Bona, M; Karyotakis, Y; Lees, J P; Poireau, V; Prencipe, E; Prudent, X; Tisserand, V ^[1]; Tico, J Garra; Grauges, E ^[2]; Lopez, L; Palano, A; Pappagallo, M ^[3]; Eigen, G; Stugu, B; Sun, L ^[4]; Abrams, G S; Battaglia, M; Brown, D N; Jacobsen, R G ^[5]

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1. Laboratoire de Physique des Particules, IN2P3/CNRS et Universite de Savoie, F-74941 Annecy-Le-Vieux (France)
2. Universitat de Barcelona, Facultat de Fisica, Departament ECM, E-08028 Barcelona (Spain)
3. INFN Sezione di Bari, I-70126 Bari (Italy)
4. University of Bergen, Institute of Physics, N-5007 Bergen (Norway)
5. Lawrence Berkeley National Laboratory and University of California, Berkeley, California 94720 (United States)

We present measurements of the semileptonic decays B{sup -}{yields}D{sup 0}{tau}{sup -}{nu}{sub {tau}}, B{sup -}{yields}D*{sup 0}{tau}{sup -}{nu}{sub {tau}}, B{sup 0}{yields}D{sup +}{tau}{sup -}{nu}{sub {tau}}, and B{sup 0}{yields}D*{sup +}{tau}{sup -}{nu}{sub {tau}}, which are sensitive to non-standard model amplitudes in certain scenarios. The data sample consists of 232x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider. We select events with a D or D* meson and a light lepton (l=e or {mu}) recoiling against a fully reconstructed B meson. We perform a fit to the joint distribution of lepton momentum and missing mass squared to distinguish signal B{yields}D{sup (*)}{tau}{sup -}{nu}{sub {tau}}({tau}{sup -}{yields}l{sup -}{nu}{sub l}{nu}{sub {tau}}) events from the backgrounds, predominantly B{yields}D{sup (*)}l{sup -}{nu}{sub l}. We measure the branching-fraction ratios R(D){identical_to}B(B{yields}D{tau}{sup -}{nu}{sub {tau}})/B(B{yields}Dl{sup -}{nu}{sub l}) and R(D{sup *}){identical_to}B(B{yields}D*{tau}{sup -}{nu}{sub {tau}})/B(B{yields}D*l{sup -}{nu}{sub l}) and, from a combined fit to B{sup -} and B{sup 0} channels, obtain the results R(D)=(41.6{+-}11.7{+-}5.2)% and R(D*)=(29.7{+-}5.6{+-}1.8)%, where the uncertainties are statistical and systematic. Normalizing to measured B{sup -}{yields}D{sup (*)0}l{sup -}{nu}{sub l} branching fractions, we obtain B(B{yields}D{tau}{sup -}{nu}{sub {tau}})=(0.86{+-}0.24{+-}0.11{+-}0.06)% and B(B{yields}D*{tau}{sup -}{nu}{sub {tau}})=(1.62{+-}0.31{+-}0.10{+-}0.05)%, where the additional third uncertainty is from the normalization mode. We also present, for the first time, distributions of the lepton momentum, |p{sub l}{sup *}|, and the squared momentum transfer, q{sup 2}.

• OSTI ID: 21308391
• Journal Information: Physical Review. D, Particles Fields, Vol. 79, Issue 9; Other Information: DOI: 10.1103/PhysRevD.79.092002; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AMPLITUDES
B MINUS MESONS
B NEUTRAL MESONS
BRANCHING RATIO
D NEUTRAL MESONS
D PLUS MESONS
DISTRIBUTION
ELECTRON-POSITRON INTERACTIONS
MISSING MASS
MOMENTUM TRANSFER
SEMILEPTONIC DECAY
STANDARD MODEL
TAU NEUTRINOS
TAU PARTICLES