The branching fraction ratio R(D∗)≡B(¯B0→D*+τ−¯ντ)/B(¯B0→D*+μ−¯νμ) is measured using a sample of proton-proton collision data corresponding to 3.0  fb−1 of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ−→μ−¯νμντ. The semitauonic decay is sensitive to contributions from non-standard-model particles that preferentially couple to the third generation of fermions, in particular, Higgs-like charged scalars. A multidimensional fit to kinematic distributions of the candidate ¯B0 decays gives R(D∗)=0.336±0.027(stat)±0.030(syst). This result, which is the first measurement of this quantity at a hadron collider, is 2.1 standard deviations larger than the value expected from lepton universality in the standard model.

Measurement of the Ratio of Branching Fractions B (B ¯ 0 →d∗+τ- ν ¯ τ) / B (B ¯ 0 →d∗+μ- ν ¯ μ) / Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Ali, S., Alkhazov, G., Alvarez Cartelle, P., Alves, A.A., Amato, S., Amerio, S., Amhis, Y., An, L., Anderlini, L., Anderson, J., Andreassi, G., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 115:11(2015). [10.1103/PhysRevLett.115.111803]

Measurement of the Ratio of Branching Fractions B (B ¯ 0 →d∗+τ- ν ¯ τ) / B (B ¯ 0 →d∗+μ- ν ¯ μ)

Capriotti, L.;Casse, G.;SARTI, ALESSIO;SCIUBBA, Adalberto;
2015

Abstract

The branching fraction ratio R(D∗)≡B(¯B0→D*+τ−¯ντ)/B(¯B0→D*+μ−¯νμ) is measured using a sample of proton-proton collision data corresponding to 3.0  fb−1 of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ−→μ−¯νμντ. The semitauonic decay is sensitive to contributions from non-standard-model particles that preferentially couple to the third generation of fermions, in particular, Higgs-like charged scalars. A multidimensional fit to kinematic distributions of the candidate ¯B0 decays gives R(D∗)=0.336±0.027(stat)±0.030(syst). This result, which is the first measurement of this quantity at a hadron collider, is 2.1 standard deviations larger than the value expected from lepton universality in the standard model.
2015
Branching fraction CP violation Flavor physics Rare decay Hadron-Hadron scattering (experiments)
01 Pubblicazione su rivista::01a Articolo in rivista
Measurement of the Ratio of Branching Fractions B (B ¯ 0 →d∗+τ- ν ¯ τ) / B (B ¯ 0 →d∗+μ- ν ¯ μ) / Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Ali, S., Alkhazov, G., Alvarez Cartelle, P., Alves, A.A., Amato, S., Amerio, S., Amhis, Y., An, L., Anderlini, L., Anderson, J., Andreassi, G., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 115:11(2015). [10.1103/PhysRevLett.115.111803]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/836168
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