Related papers: Heavy Quarks, Origin of Mass, and CP Violation for…
A Higgs-like new boson with mass around 126 GeV is now established, but its true nature probably cannot be settled with 2011--2012 LHC data. We assume it is a dilaton with couplings weaker than the Higgs boson (except to $\gamma\gamma$ and…
How to account for the matter predominance of our Universe is a fundamental issue at the core of our existence. One condition is CP violation, but the Standard Model falls short by more than $10^{-10}$. Taking cue from a recent result from…
We investigate the quark sector of a four-Higgs-doublet model with an exact D_5 symmetry. In the framework of explicit CP violation, we considered the most general real vacuum, derived the quark mass matrices, and performed a numerical fit…
The baryon asymmetry of the Universe requires CP violation, but the Standard Model falls short by a factor of $10^{-10}$ or more. Starting from a clue at the $B$ factories, we point out that the large Yukawa couplings of the sequential…
Yukawa couplings of electroweak Goldstone bosons can be inferred from experiment, but the existence of an elementary Higgs boson is not yet an established fact. If a sequential chiral quark generation does exist, it would bring us now into…
It is shown that in the scheme with a rotating fermion mass matrix (i.e. one with a scale-dependent orientation in generation space) suggested earlier for explaining fermion mixing and mass hierarchy, the theta-angle term in the QCD action…
The infamous strong CP problem in particle physics can in principle be solved by a massless up quark. In particular, it was hypothesized that topological effects could substantially contribute to the observed nonzero up-quark mass without…
We analyse the strength of CP violation in an extension of the standard model with an extra $Q=-1/3$ vector-like singlet quark, in the framework of the hypothesis of universality of strength of Yukawa couplings connecting standard quarks.…
A standing mystery in the Standard Model is the unnatural smallness of the strong CP violating phase. A massless up quark has long been proposed as one potential solution. A lattice calculation of the constants of the chiral Lagrangian…
We examine loop-mediated effects of new heavy quarks Q=(t',b') on t tbar production at hadron colliders, using a phenomenological model with flavor off-diagonal couplings of charged and neutral scalars phi=(phi^+-,phi^0) to Q. We show that…
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 find a solution to the Strong CP problem that may be testable at the LHC and future colliders. In this solution CP is broken by parity conserving terms, while parity breaking VEVs conserve CP. The quark mass matrix is Hermitian at the…
The explanation of the large CP asymmetries in $D^0\to (\pi^+\pi^-, K^+K^-)$ decays observed by the LHCb collaboration is likely to call for new physics beyond the CKM paradigm. We explore new contributions caused by the color-sextet scalar…
We use the associated production of top-quark pairs with a generic scalar boson at the LHC to explore the sensitivity of a large set of observables to the sign of the CP mixing angle, present in the coupling between the scalar boson and the…
Inspired by the vector-like phenomenon of chiral gauge theories at short distances, we postulate that the $W^\pm$-gauge boson has a vector-like gauge coupling in the high-energy region, beside its purely right-handed gauge coupling observed…
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…
A new solution to the strong CP problem with distinct experimental signatures at the LHC is proposed. It is based on the Yukawa interactions between mirror quarks, Standard Model (SM) quarks and Higgs singlets. (Mirror quarks and leptons…
The CP violating Dashen phase in QCD is predicted by chiral perturbation theory to occur when the up-down quark mass difference becomes sufficiently large at fixed down-quark mass. Before reaching this phase, all physical hadronic masses…
A new solution to the strong CP problem with distinct experimental signatures (long-lived particles) at the LHC is proposed. It is based on the Yukawa interactions between mirror quarks, Standard Model (SM) quarks and Higgs singlets.…
We propose a solution to the strong CP problem that specifically relies on massless quarks and has no light axion. The QCD color group $SU(3)_c$ is embedded into a larger, simple gauge group (grand-color) where one of the massless, colored…