Flavor models for $\bar{B} \to D^{(*)} \tau \bar{\nu}$

By M. Freytsis, Z. Ligeti, J. Ruderman. 2015

215 citations recorded by the source corpus.

The ratio of the measured $\bar B\to D^{(*)}\ell\bar{\nu}$ decay rates for $\ell = \tau$ vs. $e,\mu$ deviate from the Standard Model (SM) by about $4\sigma$. We show that the data are in tension with the SM, independent of form factor calculations, and we update the SM prediction for $\mathcal{B}(B\to X_c\tau\bar{\nu}) / \mathcal{B}(B\to X_c \ell\bar{\nu})$. We classify the operators that can accommodate the measured central values, as well as their UV completions. We identify models with leptoquark mediators that are minimally flavor violating in the quark sector, and are minimally flavor violating or $\tau$-aligned in the lepton sector. We explore experimental signatures of these scenarios, which are observable in the future at ATLAS/CMS, LHCb, or Belle II.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/5002fe2ab67f06c24ac44e4bf5ef5739d2ccb7f2

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In Nuclear and High Energy Physics

Citations in the corpus

Opportunities in Flavour Physics at the HL-LHC and HE-LHC (2018, background): “Possible mediators, assuming they couple only to SM fields, were classified in [1028].”
Simultaneous explanation of the RK and R(D(⁎)) puzzles (2014, background): “[35, 53] it was shown that six different types of leptoquark (LQ) models can explain RD(∗) .”
Revisiting the one leptoquark solution to the R(D(∗)) anomalies and its phenomenological implications (2016, methodology): “Fitting to the current experimental data on the ratios R(D(∗)) and the q spectra of B̄ → D(∗)τ ν̄τ , four best-fit solutions denoted by PA, PB, PC and PD are obtained [14].”