$(g-2{)}_{\mu }$, Lepton Flavour Violation and $Z$ Decays with Leptoquarks: Correlations and Future Prospects

Abstract

The long-standing anomaly in the anomalous magnetic moment of the muon indicates the presence of chirality violating new physics contributions. A possible solution involves scalar leptoquarks with left- and right-handed couplings to the top quark. Two such representations of scalar leptoquarks exist for which the contribution to $(g-2{)}_{\mu }$ can possess an $m_t/m_{\mu }$ enhancement compared to the Standard Model. The leptoquarks also induce loop corrections to $Z$ couplings to muons which probe as well new physics contributions which possess sources of $SU(2)$ symmetry breaking and we find that this effect should be observable at future experiments as GigaZ or TLEP. Furthermore, once interactions of the leptoquark with tau leptons and electrons are present, additional correlated effects in anomalous magnetic moments, $Z\to \ell {\ell }^{\prime }$ and $\ell \to {\ell }^{\prime }\gamma$ arise, which can be used to test the model and to determine the flavour structure of the couplings. We find that the two representations of leptoquarks can be distinguished also from low energy experiments: one representation predicts constructive interference with the Standard Model in $Z$ couplings to leptons and effects in $B\to K^{(\star )}\nu \bar{\nu }$, while the other representation interferes destructively with the Standard Model in $Z$ couplings to leptons and gives a $C_9=C_{10}$-like contribution to $b\to s{\ell }^{+}{\ell }^{-}$ processes.

6 pages, 3 figures

References in corpus (10)

• Secluded U(1) below the weak scale
• Hadronic contribution to the muon anomalous magnetic moment to next-to-next-to-leading order
• Neutrino Trident Production: A Powerful Probe of New Physics with Neutrino Beams
• The Muon Magnetic Moment and Supersymmetry
• Limiting two-Higgs-doublet models
• Lepton flavor violating Z' explanation of the muon anomalous magnetic moment
• Leptoquarks, Dark Matter, and Anomalous LHC Events
• A light pseudoscalar of 2HDM confronted with muon g-2 and experimental constraints
• Massive vectors and loop observables: the $g-2$ case
• Minimal muon anomalous magnetic moment

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• Muon anomalous magnetic moment in the standard model extension
• Scalar leptoquarks at the LHC and flavour anomalies: a comparison of pair-production modes at NLO-QCD
• Impact of Lorentz violation on anomalous magnetic moments of charged leptons
• Searching for new physics from SMEFT and leptoquarks at the P2 experiment
• Quark and lepton flavor model with leptoquarks in a modular $A_4$ symmetry
• Leptonic $g-2$ anomaly in an extended Higgs sector with vector-like leptons