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arXiv · 2108.00013

Perturbative unitarity constraints on generic Yukawa interactions

Lukas Allwicher·Pere Arnan·Daniele Barducci·Marco Nardecchia
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Abstract

We study perturbative unitarity constraints on generic Yukawa interactions where the involved fields have arbitrary quantum numbers under an $\prod_i SU(N_i) \otimes U(1)$ group. We derive compact expressions for the bounds on the Yukawa couplings for the cases where the fields transform under the trivial, fundamental or adjoint representation of the various $SU(N)$ factors. We apply our results to specific models formulated to explain the anomalous measurements of $(g-2)_\mu$ and of the charged- and neutral-current decays of the $B$ mesons. We show that, while these models can generally still explain the observed experimental values, the required Yukawa couplings are pushed at the edge of the perturbative regime.

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Lukas Allwicher, Pere Arnan, Daniele Barducci, Marco Nardecchia. 2021-07-30. Perturbative unitarity constraints on generic Yukawa interactions. https://doi.org/10.1007/jhep10(2021)129

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