Related papers: Estimating epsilon'/epsilon in the Standard Model
Based on the calculations using the lattice QCD by RBC-UKQCD collaboration and a large $N_c$ dual QCD, the resulted $\epsilon'/\epsilon$, which is less than the experimental data by more than a $2\sigma$ in the standard model (SM), suggests…
I discuss the quark mass dependence of various baryon properties derived from chiral perturbation theory. Such representations can eventually be used as chiral extrapolation functions when lattice data at sufficiently small quark masses…
Chiral-scale perturbation theory $\chi$PT$_\sigma$ has been proposed as an alternative to chiral $SU(3)_L\times SU(3)_R$ perturbation theory which explains the $\Delta I = 1/2$ rule for kaon decays. It is based on a low-energy expansion…
We investigate the $\epsilon^{\prime} /\epsilon$ for $K\to \pi\pi$ in a sequential fourth generation model. By giving the basic formulae for $\epsilon^{\prime}/\epsilon$ in this model, we analyze the numerical results which are dependent of…
We perform an isospin analysis of $B$ decays to two pseudoscalars. The analysis extracts appropriate CKM and short distance loop factors to allow for comparison of non-perturbative QCD effects in the reduced matrix elements of the…
We perform a chiral extrapolation of lattice data on the scalar K pi form factor and the ratio of the kaon and pion decay constants within Chiral Perturbation Theory to two loops. We determine the value of the scalar form factor at zero…
We analyze the rare decay mode $B \to \phi \pi $, which is a pure penguin induced process, receiving dominant contribution from the electroweak penguins. Thus the standard model branching ratio is expected to be very small, which makes it…
We perform a next-to-next-to-leading order (NNLO) QCD analysis of the charm-top-quark contribution eta_ct to the effective Delta S = 2 Hamiltonian in the Standard Model. eta_ct represents an important part of the short distance contribution…
Recent ALEPH/OPAL data on the V-A spectral functions from hadronic tau decays are used for fixing the QCD continuum threshold at which the first and second Weinberg sum rules should be satisfied in the chiral limit, and for predicting the…
We consider the exclusive B_s -> phi mu+ mu- process in the standard model using a constituent quark loop model approach together with a simple parameterization of the quark dynamics. The model allows to compute the decay form factors and…
We present results for Delta I=3/2 and Delta S=2 matrix elements relevant for CP violation in K->Pi Pi decays and for the K_S-K_L mass difference in the standard model and beyond. They were obtained with Neuberger fermions on quenched gauge…
The hadronic decays eta' -> eta pi pi are studied in the frameworks of large-Nc Chiral Perturbation Theory, at lowest and next-to-leading orders, and Resonance Chiral Theory in the leading 1/Nc approximation. Higher order effects such as…
We study the $\Delta I = 1/2$ rule for kaon decays and the $B_K$ parameter for $K^0 - {\bar K}^0$ mixing in a dual 5-dimensional holographic QCD model. We perform, in the chiral limit, computations of the relevant four-point current-current…
On the basis of a next-to-leading-order calculation in chiral perturbation theory, the first complete analysis of isospin breaking for direct CP violation in K^0 -> 2 pi decays is performed. We find a destructive interference between three…
We quantify the important effect of strong final state interactions in the weak $K\to2\pi$ amplitudes, using the measured $\pi$--$\pi$ phase shifts with J=0 and $I=0,2$. The final rescattering of the two pions provides a strong enhancement…
Recently the RBC-UKQCD lattice collaboration presented new results for the hadronic matrix elements relevant for the ratio $\varepsilon'/\varepsilon$ in the Standard Model (SM). With the present knowledge of the Wilson coefficients and…
In this Ph.D. Thesis we analyze some CP-violating observables in Kaon decays. In Chapters 1-3 we describe the framework in which this Thesis has been developed and establish the definitions and notation. In Chapter 4 we study CP-violating…
In the calculation of non-leptonic weak decay rates, a "mismatch" arises when the QCD evolution of the relevant weak hamiltonian down to hadronic scales is performed in unquenched QCD, but the hadronic matrix elements are then computed in…
We consider the gluon dipole penguin operator contributions to $\epsilon'/\epsilon$ and CP violation in hyperon decays. It has been proposed by Bertolini et al. that the contribution to $\epsilon'/\epsilon$ may be significant. We show that…
We analyse for the first time the CP violating ratio $\varepsilon'/\varepsilon$ in $K\to \pi\pi$ decays in leptoquark (LQ) models. Assuming a mass gap to the electroweak (EW) scale, the main mechanism for LQs to contribute to…