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arXiv · 2406.03387

Measurement of the branching fraction ratios $R(D^{+})$ and $R(D^{*+})$ using muonic $\tau$ decays

LHCb collaboration·R. Aaij·A. S. W. Abdelmotteleb·C. Abellan Beteta·F. Abudinén·T. Ackernley·A. A. Adefisoye·B. Adeva·M. Adinolfi·P. Adlarson·C. Agapopoulou·C. A. Aidala·Z. Ajaltouni·S. Akar·K. Akiba·P. Albicocco·J. Albrecht·F. Alessio·M. Alexander·Z. Aliouche·P. Alvarez Cartelle·R. Amalric·S. Amato·J. L. Amey·Y. Amhis·L. An·L. Anderlini·M. Andersson·A. Andreianov·P. Andreola·M. Andreotti·D. Andreou·A. Anelli·D. Ao·F. Archilli·M. Argenton·S. Arguedas Cuendis·A. Artamonov·M. Artuso·E. Aslanides·M. Atzeni·B. Audurier·D. Bacher·I. Bachiller Perea·S. Bachmann·M. Bachmayer·J. J. Back·P. Baladron Rodriguez·V. Balagura·W. Baldini·H. Bao·J. Baptista de Souza Leite·M. Barbetti·I. R. Barbosa·R. J. Barlow·M. Barnyakov·S. Barsuk·W. Barter·M. Bartolini·J. Bartz·F. Baryshnikov·J. M. Basels·G. Bassi·B. Batsukh·A. Bay·A. Beck·M. Becker·F. Bedeschi·I. B. Bediaga·S. Belin·V. Bellee·K. Belous·I. Belov·I. Belyaev·G. Benane·G. Bencivenni·E. Ben-Haim·A. Berezhnoy·R. Bernet·S. Bernet Andres·A. Bertolin·C. Betancourt·F. Betti·J. Bex·Ia. Bezshyiko·J. Bhom·M. S. Bieker·N. V. Biesuz·P. Billoir·A. Biolchini·M. Birch·F. C. R. Bishop·A. Bitadze·A. Bizzeti·T. Blake·F. Blanc·J. E. Blank·S. Blusk·V. Bocharnikov·J. A. Boelhauve
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Abstract

The branching fraction ratios of $\overline{B}^0\to D^+\tau^-\overline{\nu}_{\tau}$ and $\overline{B}^0\to D^{*+}\tau^-\overline{\nu}_{\tau}$ decays are measured with respect to their muonic counterparts, using a data sample corresponding to an integrated luminosity of 2.0 fb$^{-1}$ collected by the LHCb experiment in proton-proton collisions at $\sqrt{s} = 13$ TeV. The reconstructed final states are formed by combining $D^+$ mesons with $\tau^-\to\mu^-\overline{\nu}_{\mu}\nu_{\tau}$ candidates, where the $D^+$ is reconstructed via the $D^+\to K^-\pi^+\pi^+$ decay. The results are \begin{align*} R(D^{+}) &= 0.249 \pm 0.043 \pm 0.047, R(D^{*+}) &= 0.402 \pm 0.081\pm 0.085, \end{align*} where the first uncertainties are statistical and the second systematic. The two measurements have a correlation coefficient of $-0.39$ and are compatible with the Standard Model.

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LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, C. A. Aidala, Z. Ajaltouni, S. Akar, K. Akiba, P. Albicocco, J. Albrecht, F. Alessio, M. Alexander, Z. Aliouche, P. Alvarez Cartelle, R. Amalric, S. Amato, J. L. Amey, Y. Amhis, L. An, L. Anderlini, M. Andersson, A. Andreianov, P. Andreola, M. Andreotti, D. Andreou, A. Anelli, D. Ao, F. Archilli, M. Argenton, S. Arguedas Cuendis, A. Artamonov, M. Artuso, E. Aslanides, M. Atzeni, B. Audurier, D. Bacher, I. Bachiller Perea, S. Bachmann, M. Bachmayer, J. J. Back, P. Baladron Rodriguez, V. Balagura, W. Baldini, H. Bao, J. Baptista de Souza Leite, M. Barbetti, I. R. Barbosa, R. J. Barlow, M. Barnyakov, S. Barsuk, W. Barter, M. Bartolini, J. Bartz, F. Baryshnikov, J. M. Basels, G. Bassi, B. Batsukh, A. Bay, A. Beck, M. Becker, F. Bedeschi, I. B. Bediaga, S. Belin, V. Bellee, K. Belous, I. Belov, I. Belyaev, G. Benane, G. Bencivenni, E. Ben-Haim, A. Berezhnoy, R. Bernet, S. Bernet Andres, A. Bertolin, C. Betancourt, F. Betti, J. Bex, Ia. Bezshyiko, J. Bhom, M. S. Bieker, N. V. Biesuz, P. Billoir, A. Biolchini, M. Birch, F. C. R. Bishop, A. Bitadze, A. Bizzeti, T. Blake, F. Blanc, J. E. Blank, S. Blusk, V. Bocharnikov, J. A. Boelhauve. 2024-06-05. Measurement of the branching fraction ratios $R(D^{+})$ and $R(D^{*+})$ using muonic $\tau$ decays. https://doi.org/10.1103/physrevlett.134.061801

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