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Published September 7, 2012 | Published
Journal Article Open

Evidence for an Excess of B → D^(*)τ^-ν_τ Decays


Based on the full BABAR data sample, we report improved measurements of the ratios R(D^(*))=B(B → D^(*)τ^-ν_τ)/B(B → D^(*)ℓ_ℓ^-ν_ℓ), where ℓ is either e or μ. These ratios are sensitive to new physics contributions in the form of a charged Higgs boson. We measure R(D)=0.440±0.058±0.042 and R(D^*)=0.332±0.024±0.018, which exceed the standard model expectations by 2.0σ and 2.7σ, respectively. Taken together, our results disagree with these expectations at the 3.4σ level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model.

Additional Information

© 2012 American Physical Society. Received 31 May 2012; published 6 September 2012. We acknowledge M. Mazur for his help throughout the analysis and S. Westhoff, S. Fajfer, J. Kamenik, and I. Nišandžić for their help with the calculation of the charged Higgs contributions. We are grateful for the excellent luminosity and machine conditions provided by our PEPII colleagues and for the substantial dedicated effort from the computing organizations that support BABAR. The collaborating institutions thank SLAC for its support and kind hospitality. This work is supported by DOE and NSF (USA), NSERC (Canada), CEA and CNRS-IN2P3 (France), BMBF and DFG (Germany), INFN (Italy), FOM (Netherlands), NFR (Norway), MES (Russia), MICIIN (Spain), and STFC (United Kingdom). Individuals have received support from the Marie Curie EIF (European Union) and the A. P. Sloan Foundation (USA).

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Published - PhysRevLett.109.101802.pdf


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August 19, 2023
October 19, 2023