Related papers: pi^0-eta Mixing and CP Violation

Cascade mixing provides an elegant place to study the $B^0-\bar{B^0}$ mixing. We use this idea to study the CPT violation caused by $B^0-\bar{B^0}$ mixing. An approximation method is adopted to treat the two complex $B^0-\bar{B^0}$ mixing…

We study the radiative decay $\phi\to\pi^{0}\eta\gamma$ within the framework of a phenomenological approach in which the contributions of $\rho$-meson, chiral loop and $a_0$-meson are considered. We analyze the interference effects between…

The $\eta \to 3\pi$ decays are a valuable source of information on low energy QCD. Yet they were not used for an extraction of the three flavor chiral symmetry breaking order parameters until now. We use a Bayesian approach in the framework…

We derive the subleading contributions to the two-pion-one-pion exchange and ring three-nucleon force topologies emerging at next-to-next-to-next-to-next-to-leading order in chiral effective field theory. The resulting expressions do not…

We show that in a recently proposed $S_3$ model for tri-bimaximal mixing pattern for neutrinos, CP violating phases in neutrino mixings are directly responsible for lepton asymmetry $\epsilon_\ell$. In the exact tri-bimaximal limit,…

The radiative $\phi\to\pi^0\eta\gamma$ decay is discussed emphasizing the effects of the $a_0$(980) scalar resonance which dominates the high values of the $\pi^0\eta$ invariant mass spectrum. In its lowest part, the proposed amplitude…

We investigate omega-phi meson mixing to leading order in chiral perturbation theory utilizing the antisymmetric tensor field formulation. We update the quark mass ratio R from rho-omega mixing, R = 42 \pm 4.

We have recently shown that the large direct CP violation observed in the decay B^0 -> pi^+ pi^-, and the enhanced branching ratio for B^0 -> pi^0 pi^0, can be understood by invoking a small mixing of the pi pi system with the dominant D…

We consider chiral perturbation theory (ChPT) with a non-zero theta term. Due to the CP violating term, the vacuum of chiral fields is shifted to a non-trivial element on the SU(N_f) group manifold. The CP violation also provides mixing of…

The charge-symmetry-breaking amplitudes for the recently observed d d -> alpha pi0 reaction are investigated. Chiral perturbation theory is used to classify and identify the leading-order terms. Specific forms of the related one- and…

In tagged cascade decays of the type P^0 (P^0-bar) -> M^0 / M^0-bar X -> f X there are two complex CPT-violating parameters: one in P^0 - P^0-bar mixing, the other one in M^0 - M^0-bar mixing. I analyze those decays and find that, in…

In this lecture, I will review results on the study of direct CP violation- where the violation occurs in a particle decay rather than in particle-anti particle mixing. Brief comments on rare decays, particularly those with a CP reach, will…

We show that the CP-violating effect in K^0 vs \bar K^0-->\pi^+\pi^-\pi^0 decays differs from that in K_{\rm L}-->\pi^+\pi^-, K_{\rm L}-->\pi^0\pi^0 or the semileptonic K_{\rm L} transitions, if there exists CPT violation in K^0-\bar{K}^0…

As a first step, a simple and pedagogical recall of the $\eta$-$\eta'$ system is presented, in which the role of the axial anomaly, related to the heterochiral nature of the multiplet of (pseudo)scalar states, is underlined. As a…

The isospin violating $J/\Psi\to \phi \pi^0 \eta$ decay is thought to be dominated by the mixing of the $f_0(980)$ and $a_0(980)$ scalar resonances. We make a theoretical evaluation of the $J/\Psi\to \phi \pi^0 \eta$ decay extending our own…

The charmonium transitions from the $\chi_{cJ}$ states to $\eta_c$ with emission of one or two pions are considered. It is shown that the only processes of such type arising in the leading order in the QCD multipole expansion are the decays…

In the framework of the chiral perturbation theory we computed two- and three-loop corrections to the pion parton distributions which posses $\delta$-function singularities at x->0. This calculation explicitly demonstrates that in the…

In perturbative QCD approach, based on the first order of isospin symmetry breaking, we study the direct $CP$ violation in the decay of $\bar{B}_s^0\to\rho(\omega )K^{*0}\to {\pi^+}{\pi^-}K^{*0}$. An interesting mechanism is applied to…

A simple analysis of time-dependent $B_s\to K^+K^-$ transitions, based on recent results from the LHCb experiment, is presented. The benefits of adopting a fully consistent theoretical description of the $B^0_s$--$\bar B^0_s$ mixing are…

This talk describes the reasons why $\eta$ and $\eta^\prime$ decays are an interesting topic of study for both theory and experiment. The main part discusses the results of the recent calculation of $\eta\to3\pi$ at two-loop order in ChPT.…