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CP violation in \( {\overline{B}}^0\to {D}^{\ast +}{\mu}^{-}{\overline{\nu}}_{\mu } \)

A preprint version of the article is available at arXiv.


In order to explain the observed anomalies in the measurements of \( {R}_{D^{\left(\ast \right)}} \) and RJ/ψ, a variety of new-physics (NP) models that contribute to \( b\to c{\tau}^{-}\overline{\nu} \) have been proposed. In this paper, we show how CP-violating observables can be used to distinguish these NP models. Because \( {\overrightarrow{p}}_{\tau } \) cannot be measured (the decay products of the τ include the undetected ντ), obtaining the angular distribution of \( {\overline{B}}^0\to {D}^{\ast +}{\tau}^{-}{\overline{\nu}}_{\tau } \) is problematic. Instead, we focus here on \( {\overline{B}}^0\to {D}^{\ast +}\left(\to {D}^0{\pi}^{+}\right){\mu}^{-}{\overline{\nu}}_{\mu } \). This process may also receive contributions from the same NP, and LHCb intends to measure the CP-violating angular asymmetries in this decay. There are two classes of NP models that contribute to \( b\to c{\mu}^{-}{\overline{\nu}}_{{}_{\mu }} \). These involve (i) a W (two types) or (ii) a leptoquark (LQ) (six types). The most popular NP models predict no CP-violating effects, so the measurement of nonzero CP-violating asymmetries would rule them out. Furthermore these measurements allow one to distinguish the W and LQ models, and to differentiate among several LQ models.


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Bhattacharya, B., Datta, A., Kamali, S. et al. CP violation in \( {\overline{B}}^0\to {D}^{\ast +}{\mu}^{-}{\overline{\nu}}_{\mu } \). J. High Energ. Phys. 2019, 191 (2019).

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  • Beyond Standard Model
  • CP violation