Related papers: $A_4$ modular invariance and the strong CP problem
We constructed a four-Higgs-doublet model (4HDM) invariant under D_5 symmetry and investigated its complete neutral vacuum structure in detail. Assuming explicit CP conservation in the scalar potential, we examined whether CP symmetry can…
String compactifications on an orbi-folded torus with complex structure give rise to chiral fermions, spontaneously broken CP, modular invariance. We show that this allows simple effective theories of flavour and CP where: i) the QCD angle…
We propose theories of a complete mirror world with parity (P) solving the strong CP problem. P exchanges the entire Standard Model (SM) with its mirror copy. We derive bounds on the two new mass scales that arise: $v'$ where parity and…
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…
We investigate a composite model of spontaneous CP violation based on a new supersymmetric QCD as a solution to the strong CP problem. The scalar components of the meson chiral superfields obtain complex vacuum expectation values to break…
We characterize CP violation in the SU(2)xU(1) model due to an extra vector-like quark or sequential family, giving special emphasis to the chiral limit m_{u,d,s}=0. In this limit, CP is conserved in the three generation Standard Model…
We constructed rephasing invariant measures of CP violation with elements of the neutrino mass matrix, in the basis in which the charged lepton mass matrix is diagonal. We discuss some examples of neutrino mass matrices with texture zeroes,…
Weak bases of flavors (u, c), (d,s), (e, \mu), (\nu_e,\nu_\mu) are assumed as the S_3 doublet and t, b, \tau, {\nu_\tau} are the S_3 singlet and further there are assumed S_3 doublet Higgs (H_1, H_2) and S_3 singlet Higgs H_S. We suggest an…
We study spontaneous CP violation as a solution to the strong CP problem in left-right symmetric theories. The discrete CP symmetry is broken by a complex vacuum expectation value of a right-handed Higgs doublet. Heavy vectorlike down-type…
We propose models to explain the hierarchies of the quark masses and mixing by utilizing the $S_4^\prime$ modular flavor symmetry. The hierarchy is realized by the modulus $\tau$ stabilized at $\mathrm{Im}\,\tau \gg 1$, where the residual…
By analogy with an effective model of charged-lepton mass matrix that, with the inputs of $m^{exp}_e $ and $m^{exp}_\mu$, predicts (in a perturbative zero order) $m_\tau = 1776.80 $ MeV close to $m^{exp}_\tau = 1777.03^{+0.30}_{-0.26}$ MeV,…
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…
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…
One may argue that QCD solves the strong CP problem by itself, without having to introduce new symmetries and particles. To test this idea, a lattice simulation is performed. The problem is investigated in the CP$^3$ model first. It is…
We study the CP-violating phase of the quark sector in the $U(8)$ flavor model on $T^2/Z_N \, (N=2,3,4,6)$ with non-vanishing magnetic fluxes, where properties of possible origins of the CP violation are investigated minutely. In this…
The $D_4$ flavor model based on $\mathrm{SU}(3)_C \otimes \mathrm{SU}(3)_L \otimes \mathrm{U}(1)_X$ gauge symmetry that aims at describing quark mass and mixing is updated. After spontaneous breaking of flavor symmetry, with the constraint…
Experimental data have provided stringent constraints on neutrino mixing parameters. In the standard parameterization the mixing angle $\theta_{23}$ is close to $\pi/4$. There are also evidences show that the CP violating phase is close to…
We present a model for quark masses and mixing, featuring geometrical CP violation through a \Delta(27) triplet. By employing a single U(1)_F or Z_N symmetry in addition to \Delta(27), we forbid all terms in the scalar potential that would…
A ${\cal G}_{\cal F}=SU(3)_{Q}\times SU(3)_{u}\times SU(3)_{d}$ invariant scalar potential breaking spontaneously the quark flavor symmetry can explain the standard model flavor puzzle. The approximate alignment in flavor space of the…
We study the CP violation effects from two types of neutrino mass matrices with (i) $(M_\nu)_{ee}=0$, and (ii) $(M_\nu)_{ee}=(M_\nu)_{e\mu}=0$, which can be realized by the high dimensional lepton number violating operators $\bar…