Faculty and Student Publications
Document Type
Article
Publication Date
7-1-2020
Abstract
© 2020, The Author(s). At present, the measurements of RD and RJ/ψ hint at new physics (NP) in b→ cτ−v¯ decays. The angular distribution of B¯ → D (→ Dπ) τ−v¯ τ would be useful for getting information about the NP, but it cannot be measured. The reason is that the three-momentum p→ τ cannot be determined precisely since the decay products of the τ− include an undetected ντ. In this paper, we construct a measurable angular distribution by considering the additional decay τ−→ π−ντ. The full process is B¯→D(→Dπ′)τ−(→π−vτ)v¯τ, which includes three final-state particles whose three-momenta can be measured: D, π′, π−. The magnitudes and relative phases of all the NP parameters can be extracted from a fit to this angular distribution. One can measure CP-violating angular asymmetries. If one integrates over some of the five kinematic parameters parametrizing the angular distribution, one obtains (i) familiar observables such as the q2 distribution and the D polarization, and (ii) new observables associated with the π− emitted in the τ decay: the forward-backward asymmetry of the π− and the CP-violating triple-product asymmetry.
Relational Format
journal article
Recommended Citation
Bhattacharya, B., Datta, A., Kamali, S., & London, D. (2020). A measurable angular distribution for ��→��(∗)��−��⎯⎯⎯��B¯→D(∗)τ−v¯τ decays. Journal of High Energy Physics, 2020(7), 194. https://doi.org/10.1007/JHEP07(2020)194