Related papers: Solving the strong CP problem with horizontal gaug…
Simply based on CP arguments, we argue against a Standard Model explanation of the baryon asymmetry of the universe in the presence of a first order phase transition. A CP-asymmetry is found in the reflection coefficients of quarks hitting…
In the minimal Left-Right model the choice of left-right symmetry is twofold: either generalized parity $\mathcal P$ or charge conjugation $\mathcal C$. In the minimal model with spontaneously broken strict $\mathcal P$, a large tree-level…
The absence of a neutron electric dipole moment (EDM) constrains the quantum chromodynamics (QCD) theta angle to be less than one part in ten billion, posing the Strong $CP$ problem. We revisit two classes of proposed solutions. First, we…
We discuss theoretical and phenomenological aspects of two-Higgs-doublet extensions of the Standard Model. In general, these extensions have scalar mediated flavour changing neutral currents which are strongly constrained by experiment.…
We propose a solution to the mu/Bmu problem in gauge-mediated SUSY breaking, which does not suffer from the SUSY CP problem and is consistent with the solution to the strong CP problem. The model is based on Z_3-invariant NMSSM with…
CP violation from physics beyond the Standard Model is investigated in $B_{l4}$ decays: $B\to D\pi l\bar{\nu}_l$. In the decay process, we include various excited states as intermediate states decaying to the final hadrons, $D+\pi$. We…
We point out that the hierarchy between the measured values of the CKM phase and the strong CP phase has a natural origin in supersymmetry with spontaneous CP violation and low energy supersymmetry breaking. The underlying reason is simple…
The cosmological constant problem is a failure of naturalness and suggests that a fine-tuning mechanism is at work, which may also address the hierarchy problem. An example -- supported by Weinberg's successful prediction of the…
In this study, we numerically show that automatic Nelson-Barr models with new chiral fermions can simultaneously solve the strong CP problem and generate the observed baryon asymmetry via high-scale leptogenesis. In these models, all CP…
CP4 3HDM is a three-Higgs-doublet model based on the $CP$ symmetry of order 4 (CP4). Imposing CP4 leads to remarkable connections between the scalar and Yukawa sectors and unavoidably generates tree-level flavor-changing neutral couplings…
The QCD Lagrangian contains a CP violating gluon density term with a physical coefficient $\bar{\theta}$. The upper bound on the electric dipole moment of neutron implies that the value of $\bar{\theta}$ should be extremely small rather…
Direct CP asymmetry in semi-leptonic $\tau$ decays is an intriguing hint for new physics beyond the standard model. We investigate the CP asymmetry in $\tau^- \to K_S^0 \pi^- \nu_\tau$ and $\tau^- \to K^- \pi^0 \nu_\tau$ decays in…
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…
We construct phenomenologically viable supersymmetric models where CP is an approximate symmetry. The full high energy theory has exact CP and horizontal symmetries that are spontaneously broken with a naturally induced hierarchy of scales,…
We present simple effective theory of quark masses, mixing and CP violation with level $N=3$ ($A_4$) modular symmetry, which provides solution to the strong CP problem without the need for an axion. The vanishing of the strong CP-violating…
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…
The vanishing of the Higgs quartic coupling of the Standard Model at high energies may be explained by spontaneous breaking of Higgs Parity. Taking Higgs Parity to originate from the Left-Right symmetry of the $SO(10)$ gauge group, leads to…
We use supersymmetric chiral dynamics perturbed by anomaly-mediated supersymmetry breaking to obtain a high-quality, composite axion that solves the strong CP problem. The strong dynamics arises from a supersymmetric SU(10) chiral gauge…
We constructed a model for spontaneous CP symmetry breaking in five-dimensional space-time that has a potential to solve the strong CP problem. To explain the nature of dark matter and the baryon asymmetry of the universe, three…
We study thermal leptogenesis induced by decays of a scalar SU(2)_L triplet. Despite the presence of gauge interactions, unexpected features of the Boltzmann equations make the efficiency close to maximal in most of the parameter space. We…