Reconsidering the one leptoquark solution: flavor anomalies and neutrino mass

By Yi-Fu Cai, John Gargalionis, M. Schmidt, R. Volkas. Journal of High Energy Physics, 2017

173 citations recorded by the source corpus.

We reconsider a model introducing a scalar leptoquark ϕ ∼ (3,1, −1/3) to explain recent deviations from the standard model in semileptonic B decays. The leptoquark can accommodate the persistent tension in the decays B¯→D∗τν¯\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \overline{B}\to {D}^{\left(\ast \right)}\tau \overline{\nu} $$\end{document} as long as its mass is lower than approximately 10 TeV, and we show that a sizeable Yukawa coupling to the right-chiral tau lepton is necessary for an acceptable explanation. A characteristic prediction of this scenario is a value of RD*\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {R}_{D^{*}} $$\end{document} slightly smaller than the current world average. Agreement with the measured B¯→D∗τν¯\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \overline{B}\to {D}^{\left(\ast \right)}\tau \overline{\nu} $$\end{document} rates is mildly compromised for parameter choices addressing the tensions in b → sμμ, where the model can significantly reduce the discrepancies in angular observables, branching ratios and the lepton-flavor-universality observables RK and RK*\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {R}_{K^{*}} $$\end{document}. The leptoquark can also reconcile the predicted and measured value of the anomalous magnetic moment of the muon and appears naturally in models of radiative neutrino mass derived from lepton-number violating effective operators. As a representative example, we incorporate the particle into an existing two-loop neutrino mass scenario derived from a dimension-nine operator. In this specific model, the structure of the neutrino mass matrix provides enough freedom to explain the small masses of the neutrinos in the region of parameter space dictated by agreement with the anomalies in B¯→D∗τν¯\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \overline{B}\to {D}^{\left(\ast \right)}\tau \overline{\nu} $$\end{document}, but not the b → s transition. This is achieved without excessive fine-tuning in the parameters important for neutrino mass.

Subfields: Artificial Intelligence, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/f93b54432f9e39887b45acb8e267d4b2dfe0cc55

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Citations in the corpus

Opportunities in Flavour Physics at the HL-LHC and HE-LHC (2018, background): “The current bounds on b → sνν̄, now only O(1) above the SM [1068, 1069], can also put severe constraints on particular NP models [1070, 1071].”
From the Trees to the Forest: A Review of Radiative Neutrino Mass Models (2017, background): “The 1-loop contribution induced by the mixing of the leptoquarks vanishes, because the left-chiral coupling of one of the leptoquarks is switched off [314].”