arXiv subjects

G. H. S. Alves

Publications and source records attributed to G. H. S. Alves.

2 recordsLinked to original sources

arXiv2026

Nelson-Barr Models with Vector-Like Quark Doublets

We investigate Nelson--Barr solutions to the strong CP problem in which spontaneous CP violation is transmitted to the Standard Model through mixing with a vector-like partner of the SM quark doublet. We show that these constructions constitute compelling and phenomenologically viable alternatives to the more widely studied singlet-based NB models. A key result of our analysis is that an accidental symmetry of the renormalizable theory delays the leading contributions to \barθ until three loops, naturally suppressing hadronic CP violation. We outline the main phenomenological constraints, including future EDM experiments, as well as the main differences between these scenarios and generic models with doublet vector-like quarks.

hep-ph↗

arXiv2023

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

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 $\barθ$. 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 $\barθ$, although this case had been previously shown to be very restricted based on estimates.

hep-ph↗