Related papers: Spontaneous CP violation
Within the general framework of using spontaneous CP violation to solve the strong CP problem, we construct a variant Nelson-Barr model in which the Standard Model (SM) quark contribution to the strong CP phase is cancelled by new heavy…
We propose a model of soft CP violation that evades the strong CP problem and can describe observed CP violation in the neutral kaon sector, both direct and indirect. Our model requires two ``duark'' mesons carrying quark number two that…
The standard model (SM) has several issues related to the $CP$ violation which could give clues to search physics beyond the SM. They are a $CP$ phase in the CKM matrix, the strong $CP$ problem, $CP$ phases in the PMNS matrix and $CP$…
One possible solution to the strong CP problem is that CP is an exact symmetry, spontaneously broken at some scale. Some years ago, Nelson and Barr suggested a mechanism for obtaining $\theta=0$ at tree level in this framework, and showed…
We consider spontaneous CP violation in the Next to Minimal Supersymmetric Standard Model, without the usual $Z_3$ discrete symmetry. CP violation can occur at tree level, raising a potential conflict with the experimental bounds on the…
We propose an alternative to the axion mechanism for addressing the charge parity (CP) problem in quantum chromodynamics (QCD). Our approach involves imposing CP as an inherent symmetry of the Lagrangian, which is then spontaneously broken.…
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…
We present a simple model in which CP symmetry is spontaneously broken only after the radiative corrections are taken into account. The model includes two Higgs-boson doublets and two right-handed singlet neutrinos which induce the…
We study the minimal version of the supersymmetric standard model with spontaneous CP breaking. In this model, the KM matrix is real and contributions to $\varepsilon$ arise from box diagrams involving squarks. We analyze the region of the…
We re-examine spontaneous CP violation at the tree level in the context of the next-to-minimal supersymmetric standard model (NMSSM) with two Higgs doublets and a gauge singlet field. We analyse the most general Higgs potential without a…
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…
We review CP violation in various extensions of the electroweak sector of the Standard Model. A particular emphasis is put on supersymmetric models. We describe the two CP problems of supersymmetry, concerning $d_N$ and $\epsilon_K$. We…
We investigate how the solution to the strong CP problem and the explanation for the observed fermion mass hierarchies can be intrinsically related. Specifically, we explore the Nelson-Barr mechanism and identify its "seesaw limit", where…
I present a new form of spontaneous CP violation in which, in analogy with the left-right-symmetric model, CP breaking results from the inequality of two real vacuum expectation values. In my model there is no scalar-pseudoscalar mixing,…
I rebuild a conventional two-Higgs doublet model by relaxing the spontaneous CP violation and considering approximate global U(1) family symmetries. So that the domain-wall problem does not explicitly arise at the weak scale, but CP…
We discuss a simple model, based on the gauge group ${\rm SU}(3)_C\otimes {\rm SU}(2)_L \otimes \text{U}(1)_Y\otimes \text{U}(1)_R$, where the Nelson-Barr solution to the strong CP problem is implemented. This model automatically provides a…
We re-examine spontaneous $\cp$ violation (SCPV) at the tree level in the context of the next-to-minimal supersymmetric standard model (NMSSM) with two Higgs doublets and a gauge singlet field. We analyse the most general Higgs potential…
It is pointed out that the recent measurement of the angle $\gamma$ of the unitarity triangle, providing irrefutable evidence for a complex Cabibbo-Kobayashi-Maskawa (CKM) matrix, presents a great challenge for supersymmetric models with…
We explore the possibility of spontaneous CP violation within the Next to Minimal Supersymmetric Standard Model. In the most general form of the model, without a discrete $Z_3$ symmetry, we find that even at tree level spontaneous CP…
Three symmetry constraints on the CP violations in QCD are discussed in this paper. In order to generate CP violating observables from QCD, these constraints require: (1) spontaneous chiral symmetry breaking, (2) explicit chiral symmetry…