New physics contributions in $B\to \pi \tau \bar{\nu }$ and $B\to \tau \bar{\nu }$

Abstract

We study possible new physics contributions in $B\to \pi \tau \bar{\nu }$ and $B\to \tau \bar{\nu }$ employing the model-independent effective Lagrangian that describes the quark-level transition $b\to u\tau \nu$ at low energies. The decay rate of $B\to \pi \tau \bar{\nu }$ and its theoretical uncertainty are evaluated using the $B\to \pi$ form factors given by recent lattice QCD studies. Comparing theoretical results with the current experimental data, $\mathcal{B}(B\to \pi \tau \bar{\nu })<2.5\times 10^{-4}$ and $\mathcal{B}(B\to \tau \bar{\nu })=(1.14\pm 0.22)\times 10^{-4}$, we obtain constraints on the Wilson coefficients that quantify potential new physics. We also present the expected sensitivity of the SuperKEKB/Belle~II experiment.

17 pages, 4 figures, 1 table; revised version accepted by journal

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Cited by in corpus (7)

• Combined Explanations of the $b\to s{\mu }^{+}{\mu }^{-}$ and $b\to c{\tau }^{-}\bar{\nu }$ Anomalies: a General Model Analysis
• With or without U(2)? Probing non-standard flavor and helicity structures in semileptonic B decays
• Decoding (Pseudo)-Scalar Operators in Leptonic and Semileptonic $B$ Decays
• Testing Leptoquark/EFT in $\bar{B}\to D^{(\ast )}l\bar{\nu }$ at the LHC
• Correlating Tauonic B Decays to the Neutron EDM via a Scalar Leptoquark
• Impact of vector new physics couplings on $B_s\to (K,K^{\ast })\tau \nu$ and $B\to \pi \tau \nu$ decays
• Mapping out the Space for New Physics with Leptonic and Semileptonic $B_{(c)}$ Decays