Related papers: Do Minimal Parity Solutions to the Strong CP Probl…
We find in theories with spontaneous P and CP violation that symmetries needed to set the tree level strong CP phase to zero can also set all non-zero tree level CP violating phases to the maximal value \pi / 2 in the symmetry basis…
Many extensions of the Standard Model (SM) generically introduce new sources of CP violation, which can induce observable $P$-odd and $T$-odd permanent electric dipole moments (EDMs) of nuclei, atoms, and molecules. A future observation of…
The CP violation gives rise to severe restriction of soft breaking terms in supersymmetric standard models. Among them, constraints on the holomorphic soft mass of Higgs doublets (the B parameter) are difficult to satisfy due to the other…
We consider the low energy effective chiral theory of QCD mesons and the electroweak Goldstone bosons. In this effective theory the pion sector contributes to the gauge boson masses and the Yukawa couplings of the fermions. Consequently the…
We investigate spatial behaviors of the CP-violating angle $\theta$ by solving the equation of motion of the two-Higgs-doublet model in the presence of a small explicit CP breaking $\delta$. The moduli of the two Higgs scalars are fixed to…
We study thermal production of dark matter (DM) in a realization of the minimal models of Ref.~\cite{Bonnefoy:2023afx}, where parity is used to solve the strong CP problem by transforming the entire Standard Model (SM) into a mirror copy.…
Recently, it was shown that modular symmetry may solve the strong CP problem without axions, by producing a vanishing QCD angle while generating a large quark CP violation phase. We extend this framework to finite modular groups,…
The conventional view is that a solution of the strong CP problem lies beyond QCD. A strong argument supporting this view is that the chiral expansion shows that observables depend on theta (unless a quark mass is zero); this eliminates the…
Curiously in the minimal left right symmetric model, chiral symmetry that protects the electron's mass ($m_e$), due to parity (P), implies in the symmetry limit the vanishing of its neutrino mixing angles. We break the chiral symmetry…
We derive sufficient conditions that guarantee a robust solution of the strong CP problem in theories with spontaneous CP violation, and introduce a class of models satisfying these requirements. In the simplest scenarios the dominant…
Models that combine Abelian horizontal symmetries and spontaneous CP violation can (i) explain the smallness and hierarchy in quark parameters; (ii) satisfactorily suppress supersymmetric contributions to flavor changing neutral current…
The Standard Model contains a natural source for CP asymmetries in weak decays, which is described by the KM mechanism. Beyond $\epsilon _K$ it generates only elusive manifestations of CP violation in {\em light-}quark systems. On the other…
We discuss a possible solution to the strong CP problem which is based on spontaneous CP violation and discrete symmetries. At the same time we predict in a simple way the almost right-angled quark unitarity triangle angle ($\alpha \simeq…
Setting aside anthropic arguments, there is no reason for CP symmetry to be obeyed within the theory of quantum chromodynamics. However, no such violation of CP symmetry has ever been observed in a strongly interacting experiment. This is…
Effective coupling constant in quantum electrodynamics is investigated. A pole appears in the effective coupling constant for the space-like momentum if it is calculated by perturbation. The pole can be eliminated by the analytic…
Within the minimal Left-Right (LR) symmetric model we revisit the predictions for the kaon CP violating observables $\varepsilon$ and $\varepsilon'$ in correlation with the neutron electric dipole moment. We perform a complete study of the…
The origin of CP violation is a major mystery, especially in relation to the strong CP problem. CP being a spontaneously broken symmetry could provide an elegant solution. However, such models have difficulty making themselves compatible…
Supersymmetric models with an approximate CP, $10^{-3} \lsim \phi_{CP} \ll 1$, are a viable framework for the description of nature. The full high energy theory has exact CP and horizontal symmetries that are spontaneously broken with a…
A possible solution to the strong CP problem is presented without using an axion. The model is based on the framework of the supersymmetric vectorlike theory with the spontaneous breakdown of the P-C-T-invariance. It is shown that the…
We suggest a solution to the strong CP problem in which there are no axions involved. The superselection rule of the \theta-vacua is dynamically lifted in such a way that an infinite number of vacua are accumulated within the…