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arXiv · 2304.06078

Explicit parametrization of more than one vector-like quark of Nelson-Barr type

G. H. S. Alves·A. L. Cherchiglia·C. C. Nishi
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Abstract

Nelson-Barr models solve the strong CP problem based on spontaneous CP violation and generically requires vector-like quarks (VLQs) mixing with standard quarks to transmit the CP violation. We devise an explicit parametrization for the case of two VLQs of either down-type or up-type and quantitatively study several aspects including the hierarchy of the VLQ Yukawas and their irreducible contribution to $\bar{\theta}$. In particular, with the use of the parametrization, we show that a big portion of the parameter space for two up-type VLQs at the TeV scale is still allowed by the constraint on $\bar{\theta}$, although this case had been previously shown to be very restricted based on estimates.

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G. H. S. Alves, A. L. Cherchiglia, C. C. Nishi. 2023-04-12. Explicit parametrization of more than one vector-like quark of Nelson-Barr type. https://doi.org/10.1103/physrevd.108.035049

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