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Title: Evidence of the Purely Leptonic Decay B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}}

Abstract

We present the first evidence of the decay B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}}, using 414 fb{sup -1} of data collected at the {upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider. Events are tagged by fully reconstructing one of the B mesons in hadronic modes. We detect the signal with a significance of 3.5 standard deviations including systematics and measure the branching fraction to be B(B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}})=(1.79{sub -0.49}{sup +0.56}(stat){sub -0.51}{sup +0.4=} 6(syst))x10{sup -4}. This implies that f{sub B}=0.229{sub -0.031}{sup +0.036}(stat){sub -0.037}{sup +0.034}(syst) GeV and is the first direct measurement of this quantity.

Authors:
; ; ; ; ; ; ; ;  [1]; ; ; ; ; ; ; ; ; ; ;  [2]
  1. Nagoya University, Nagoya (Japan)
  2. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan) (and others)
Publication Date:
OSTI Identifier:
20861513
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 97; Journal Issue: 25; Other Information: DOI: 10.1103/PhysRevLett.97.251802; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASYMMETRY; B MINUS MESONS; BRANCHING RATIO; GEV RANGE 01-10; LEPTONIC DECAY; TAU NEUTRINOS; TAU PARTICLES

Citation Formats

Ikado, K., Hayasaka, K., Hokuue, T., Iijima, T., Inami, K., Miyazaki, Y., Ohshima, T., Okabe, T., Senyo, K., Abe, K., Adachi, I., Akai, K., Akemoto, M., Flanagan, J., Furukawa, K., Gershon, T., Haba, J., Hara, K., Hazumi, M., and Iida, N.. Evidence of the Purely Leptonic Decay B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}}. United States: N. p., 2006. Web. doi:10.1103/PHYSREVLETT.97.251802.
Ikado, K., Hayasaka, K., Hokuue, T., Iijima, T., Inami, K., Miyazaki, Y., Ohshima, T., Okabe, T., Senyo, K., Abe, K., Adachi, I., Akai, K., Akemoto, M., Flanagan, J., Furukawa, K., Gershon, T., Haba, J., Hara, K., Hazumi, M., & Iida, N.. Evidence of the Purely Leptonic Decay B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}}. United States. doi:10.1103/PHYSREVLETT.97.251802.
Ikado, K., Hayasaka, K., Hokuue, T., Iijima, T., Inami, K., Miyazaki, Y., Ohshima, T., Okabe, T., Senyo, K., Abe, K., Adachi, I., Akai, K., Akemoto, M., Flanagan, J., Furukawa, K., Gershon, T., Haba, J., Hara, K., Hazumi, M., and Iida, N.. Fri . "Evidence of the Purely Leptonic Decay B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}}". United States. doi:10.1103/PHYSREVLETT.97.251802.
@article{osti_20861513,
title = {Evidence of the Purely Leptonic Decay B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}}},
author = {Ikado, K. and Hayasaka, K. and Hokuue, T. and Iijima, T. and Inami, K. and Miyazaki, Y. and Ohshima, T. and Okabe, T. and Senyo, K. and Abe, K. and Adachi, I. and Akai, K. and Akemoto, M. and Flanagan, J. and Furukawa, K. and Gershon, T. and Haba, J. and Hara, K. and Hazumi, M. and Iida, N.},
abstractNote = {We present the first evidence of the decay B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}}, using 414 fb{sup -1} of data collected at the {upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider. Events are tagged by fully reconstructing one of the B mesons in hadronic modes. We detect the signal with a significance of 3.5 standard deviations including systematics and measure the branching fraction to be B(B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}})=(1.79{sub -0.49}{sup +0.56}(stat){sub -0.51}{sup +0.4=} 6(syst))x10{sup -4}. This implies that f{sub B}=0.229{sub -0.031}{sup +0.036}(stat){sub -0.037}{sup +0.034}(syst) GeV and is the first direct measurement of this quantity.},
doi = {10.1103/PHYSREVLETT.97.251802},
journal = {Physical Review Letters},
number = 25,
volume = 97,
place = {United States},
year = {Fri Dec 22 00:00:00 EST 2006},
month = {Fri Dec 22 00:00:00 EST 2006}
}
  • We present a search for the decay B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}} in a sample of 88.9x10{sup 6} BB pairs recorded with the BABAR detector at the Stanford Linear Accelerator Center B factory. One of the two B mesons from the {upsilon}(4S) is reconstructed in a hadronic or a semileptonic final state, and the decay products of the other B in the event are analyzed for consistency with a B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}} decay. We find no evidence of a signal and set an upper limit on the branching fraction of B(B{sup -}{yields}{tau}{sup -}{nu}{sub {tau}})<4.2x10{sup -4} at the 90% confidence level.
  • We present measurements of B{sup +{yields}}D*{sup 0{tau}+{nu}}{sub {tau}}and B{sup +{yields}}D{sup 0{tau}+{nu}}{sub {tau}}decays in a data sample of 657x10{sup 6} BB pairs collected with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider. We find 446{sub -56}{sup +58} B{sup +{yields}}D*{sup 0{tau}+{nu}}{sub {tau}}events with a significance of 8.1 standard deviations, and 146{sub -41}{sup +42} B{sup +{yields}}D{sup 0{tau}+{nu}}{sub {tau}}events with a significance of 3.5 standard deviations. The latter signal provides the first evidence for this decay mode. The measured branching fractions are B(B{sup +{yields}}D*{sup 0{tau}+{nu}}{sub {tau}})=(2.12{sub -0.27}{sup +0.28}(stat){+-}0.29(syst))% and B(B{sup +{yields}}D{sup 0{tau}+{nu}}{sub {tau}})=(0.77{+-}0.22(stat){+-}0.12(syst))%.
  • 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 potentially sensitive to non-standard model amplitudes. The data sample comprises 232x10{sup 6} {upsilon}(4S){yields}BB decays collected with the BABAR detector. From a combined fit to B{sup -} and B{sup 0} channels, we obtain the branching fractions 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)% (normalized for the B{sup 0}), where the uncertainties are statistical, systematic, and normalization-mode-related.
  • The recent observation of the purely leptonic decay B{sup {+-}}{yields}{tau}{sup {+-}}{nu}{sub {tau}} at the B factories permits a sizable contribution from a charged Higgs boson (H{sup {+-}}). Such a H{sup {+-}} would also contribute to the decays D{sub s}{sup {+-}}{yields}{mu}{sup {+-}}{nu}{sub {mu}} and D{sub s}{sup {+-}}{yields}{tau}{sup {+-}}{nu}{sub {tau}}, which are being measured with increasing precision at CLEO-c. We show that the branching ratios of D{sub s}{sup {+-}}{yields}{mu}{sup {+-}}{nu}{sub {mu}} and D{sub s}{sup {+-}}{yields}{tau}{sup {+-}}{nu}{sub {tau}} could be suppressed by up to 10% from the standard model prediction, which is larger than the anticipated precision in the measurements of these decaysmore » at forthcoming BES-III.« less
  • The {tau}{sup -}{yields}{eta}{pi}{sup -}{pi}{sup +}{pi}{sup -}{nu}{sub {tau}} decay with the {eta}{yields}{gamma}{gamma} mode is studied using 384 fb{sup -1} of data collected by the BABAR detector. The branching fraction is measured to be (1.60{+-}0.05{+-}0.11)x10{sup -4}. It is found that {tau}{sup -}{yields}f{sub 1}(1285){pi}{sup -}{nu}{sub {tau}}{yields}{eta}{pi}{sup -}{pi}{sup +}{pi}{sup -}{nu}{sub {tau}} is the dominant decay mode with a branching fraction of (1.11{+-}0.06{+-}0.05)x10{sup -4}. The first error on the branching fractions is statistical and the second systematic. Note that no particle identification algorithm is applied to the charged tracks to distinguish pions from kaons. In addition, a 90% confidence level upper limit on the branchingmore » fraction of the {tau}{sup -}{yields}{eta}{sup '}(958){pi}{sup -}{nu}{sub {tau}} decay is measured to be 7.2x10{sup -6}. This last decay proceeds through a second-class current and is expected to be forbidden in the limit of isospin symmetry.« less