2026/04/02 by G. H. S. Alves, G. H. S. Alves, C. C. Nishi +2
Physics and Astronomy · #Black Holes and Theoretical Physics #CP violation #Dipole #Hadron #Mixing (physics) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #Quark #Standard Model (mathematical formulation) #Symmetry (geometry) #Top quark
paper · pdf · doi:10.1103/sy92-fyjf
openalex publication_date 2026/06/15 · openalex created_date 2026/06/16 · openalex updated_date 2026/08/05
We investigate Nelson-Barr (NB) solutions to the strong <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>C</a:mi> <a:mi>P</a:mi> </a:math> problem in which spontaneous <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>C</c:mi> <c:mi>P</c:mi> </c:math> violation is transmitted to the Standard Model (SM) through mixing with a vectorlike 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 <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mover accent="true"> <e:mi>θ</e:mi> <e:mo stretchy="false">¯</e:mo> </e:mover> </e:math> until three loops, naturally suppressing hadronic <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mi>C</i:mi> <i:mi>P</i:mi> </i:math> violation. We outline the main phenomenological constraints, including future electric dipole moment experiments, as well as the main differences between these scenarios and generic models with doublet vectorlike quarks.