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It was recently shown that domain walls from the spontaneous breaking of CP symmetry are exactly stable, and must be inflated away to recover a viable cosmology. We investigate the phenomenological implications of this result in…

High Energy Physics - Phenomenology · Physics 2023-06-13 Pouya Asadi , Samuel Homiller , Qianshu Lu , Matthew Reece

We show how the SUSY flavour and CP problems can be solved using gauged SU(3) family symmetry previously introduced to describe quark and lepton masses and mixings, in particular neutrino tri-bimaximal mixing via constrained sequential…

High Energy Physics - Phenomenology · Physics 2009-01-06 Stefan Antusch , Stephen F. King , Michal Malinsky

We present a mechanism that addresses the electroweak, the strong CP, and the flavor hierarchies of the Standard Model (including neutrino masses) in a unified way. The naturalness of the electroweak scale is solved together with the strong…

High Energy Physics - Phenomenology · Physics 2018-09-26 Oz Davidi , Rick S. Gupta , Gilad Perez , Diego Redigolo , Aviv Shalit

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.…

High Energy Physics - Phenomenology · Physics 2025-10-08 Rodolfo Ferro-Hernandez , Stefano Morisi , Eduardo Peinado

We discuss how CP violation originating in the right-handed neutrino sector can feed into the quark sector, in an otherwise CP invariant theory. The dominant effects are superweak, and we suggest that this may yield a natural resolution of…

High Energy Physics - Phenomenology · Physics 2009-10-30 B. Holdom

The Nelson-Barr (NB) mechanism to solve the strong CP problem assumes CP conservation, arranges vanishing $\bar{\theta}$ at tree-level and requires vector-like quarks (VLQs) to transmit the CP breaking to the SM. We analyze the flavor…

High Energy Physics - Phenomenology · Physics 2021-11-19 A. L. Cherchiglia , G. De Conto , C. C. Nishi

We develop a grand unified theory of matter and forces based on the gauge symmetry $SU(5)_L\times SU(5)_R$ with parity interchanging the two factor groups. Our main motivation for such a construction is to realize a minimal GUT embedding of…

High Energy Physics - Phenomenology · Physics 2024-04-17 K. S. Babu , Rabindra N. Mohapatra , Anil Thapa

The unjustly neglected method of exactly solving generalized electro-weak models - with an original spontaneous symmetry breaking mechanism based on the gauge group $SU(n)_{L}\otimes U(1)_{Y}$ - is applied here to a particular class of…

High Energy Physics - Theory · Physics 2009-08-01 Adrian Palcu

We discuss a class of models in which CP is violated softly in a heavy sector adjoined to the standard model. Heavy-sector loops produce the observed CP violation in kaon physics, yielding a tiny and probably undetectable value for…

High Energy Physics - Phenomenology · Physics 2009-09-11 Howard Georgi , Sheldon L. Glashow

A non-axion solution to the Strong CP Problem is proposed that works even in the context of gravity-mediated supersymmetry breaking. Both $\epsilon'/\epsilon$ and indirect CP violation in the $B-\bar{B}$ are predicted to be unobservably…

High Energy Physics - Phenomenology · Physics 2014-11-17 S. B. Barr

We revisit the minimal Nelson-Barr model for solving the strong CP problem through the idea of spontaneous CP breaking. The minimal model suffers from the quality problem, which means that the strong CP angle is generated by…

High Energy Physics - Phenomenology · Physics 2024-11-18 Kai Murai , Kazunori Nakayama

We analyse the properties of generic models based on an SU(3) family symmetry providing a full description of quark charged lepton and neutrino masses and mixing angles. We show that a precise fit of the resulting fermion textures is…

High Energy Physics - Phenomenology · Physics 2009-11-10 Graham G. Ross , Liliana Velasco-Sevilla , Oscar Vives

The two principles of spontaneous CP violation and natural flavor conservation can be realized in the $SU(2)_{L}\times U(1)_{Y}$ model with two Higgs doublets. In particular, this model provides a consistent application to the CP violating…

High Energy Physics - Phenomenology · Physics 2007-05-23 Yue-Liang Wu

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…

High Energy Physics - Phenomenology · Physics 2007-05-23 Subhendra Mohanty

We present a UV completion of the Standard Model in which quarks and leptons are unified under color SU(4). A single fermionic representation, the real antisymmetric, provides the building blocks to address the strong CP problem via the…

High Energy Physics - Phenomenology · Physics 2026-04-02 Clara Murgui

Nelson-Barr theories solve the strong CP problem with CP spontaneously broken at \Lambda_{CP} and transmitted to the CP conserving version of the SM through vector-like quarks (VLQs). For an arbitrary number of CP breaking scalars and VLQs,…

High Energy Physics - Phenomenology · Physics 2025-09-25 Gustavo H. S. Alves , Celso C. Nishi

There is a natural solution to the strong CP problem in the Minimal Supersymmetric Standard Model if it arises from a parity symmetric theory which is spontaneously broken to MSSM at Planck, GUT or intermediate scales. The strong CP phase…

High Energy Physics - Phenomenology · Physics 2009-10-28 Ravi Kuchimanchi

We consider theories of gauged quark flavor and identify non-invertible Peccei-Quinn symmetries arising from fractional instantons when the resulting gauge group has non-trivial global structure. Such symmetries exist solely because the…

High Energy Physics - Phenomenology · Physics 2024-02-21 Clay Cordova , Sungwoo Hong , Seth Koren

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…

High Energy Physics - Phenomenology · Physics 2014-12-15 Luca Vecchi

We put forward the conjecture that all CP violating phenomena may have a common origin. In order to illustrate our idea, we present a minimal model where CP is spontaneously broken at a high energy scale, through the phase in the vacuum…

High Energy Physics - Phenomenology · Physics 2007-05-23 G. C. Branco , P. A. Parada , M. N. Rebelo