https://doi.org/10.1140/epjc/s10052-020-08653-w
Letter
Optimized lepton universality tests in $$B\rightarrow V \ell {\bar{\nu }}$$ decays
Physik-Institut, Universität Zürich, 8057, Zurich, Switzerland
* e-mail: olcyr.sumensari@physik.uzh.ch
Received:
21
July
2020
Accepted:
10
November
2020
Published online:
20
November
2020
We propose improved lepton flavor universality (LFU) ratios in semileptonic $$P\rightarrow V \ell {\bar{\nu }}$$ decays, when comparing $$\mu $$ and $$\tau $$ modes, that minimize the theoretical form-factor uncertainties. These optimized ratios are obtained with simple cuts or reweighting of the dilepton mass distributions, which imply a minimum loss of signal on the rare tauonic modes while maximizing the cancellation of theoretical uncertainties among the two modes. We illustrate the usefulness of these observables in $$B_c\rightarrow J/\psi $$, $$B_c\rightarrow \psi (2S)$$, $$B\rightarrow D^*$$ and $$B_s\rightarrow D_s^*$$ transitions, showing that in all cases we can reach $${\mathcal {O}}(1\%)$$ uncertainties on the SM predictions of the improved LFU ratios employing conservative form-factor uncertainties.
© The Author(s), 2020
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