2017/12/31 by Debajyoti Choudhury, Anirban Kundu, Rusa Mandal +1 · 1 citation
Physics and Astronomy · #hep-ph
paper · pdf · doi:10.1016/j.nuclphysb.2018.06.022
published as Nuclear Physics B 933, 433-453 (2018) · Version accepted in Nuclear Physics B
arxiv created 2018/06/28 · arxiv updated 2018/07/05
In a recent paper arXiv:1706.08437, we have advanced a minimal resolution of some of the persistent anomalies in semileptonic B-decays. These include the neutral-current observables RK and RK^*, as well as the charged-current observables R(D) and R(D^*). Recently, it has been observed that the semileptonic decays of the Bc meson also hint at a similar type of anomaly. In this longer version, we discuss in detail why, if the anomalies are indeed there, it is a challenging task to explain the data consistently in terms of a simple and compelling new physics scenario. We find that the minimal scheme to achieve a reasonable fit involves the inclusion of just two (or, at worst, three with a possible symmetry relationship between their Wilson coefficients) new current-current operators, constructed in terms of the flavour eigenstates, augmented by a change of basis for the charged lepton fields. With only three unknown parameters, this class of models not only explain all the anomalies (including that in Bc → J/ψ ℓ ν) to a satisfactory level but also predict some interesting signatures, like B→ Kμτ, Bs→ ττ, or B→ K plus missing energy, that can be observed at LHCb or Belle-II.