相关论文: A New Estimate of $\varepsilon '/\varepsilon$

We compute the isospin $I= 0$ and 2 amplitudes for the decay of a kaon into two pions by estimating the relevant hadronic matrix elements in the chiral quark model. The results are parametrized in terms of the quark and gluon condensates…

I review a recent attempt to reproduce the isospin $I= 0$ and 2 amplitudes for the decay of a kaon into two pions by estimating the relevant hadronic matrix elements in the chiral quark model. The results are parametrized in terms of the…

Experiments at CERN and Fermilab have been competing each other to improve the measurement of a CP violation parameter, epsilon'/epsilon. Fermilab KTeV-E832 recently announced their final result, Re(epsilon'/epsilon) = [19.2 +- 2.1] x…

We review the Standard Model predictions of CP violation in kaon decays. We present an elementary introduction to Chiral Perturbation Theory, four--quark effective hamiltonians and the relation among them. Particular attention is devoted to…

The parameter epsilon_K, that quantifies CP violation in kaon mixing, is the observable setting the strongest constraints on new physics with a generic flavour and CP structure. While its experimental uncertainty is at the half percent…

We give a progress report of our lattice calculation of direct and indirect CP violation in kaon decays, parametrized as $\epsilon'/\epsilon$ and $B_K$, which require non-perturbative calculation of the matrix elements of the Standard Model…

A left-right model with spontaneous $CP$ breakdown, consistent with the particle physics phenomenology, is presented. Constraints on free parameters of the model: mass of the new right handed gauge boson $M_2$ and ratio $r$ of the two…

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…

This is a pedagogical review of some selected topics of CP and T violation in the decays of K mesons. Diagonalization of the quark mass matrix and the emergence of the complex phase in both the standard and the left--right symmetric models…

The direct CP violation parameter Re(epsilon'/epsilon) has been measured from the decay rates of neutral kaons into two pions using the NA48 detector at the CERN SPS. With 3.3 million KL->pi0pi0 events collected during the 1998 and 1999…

The CP-violating parameter eps'/eps is estimated in a novel way by including the explicit computation of eps in the ratio as opposed to the usual procedure of taking its value from the experiments. This approach has the advantage of being…

We have compared the decay rates of K_L and K_S to \pi^+ \pi^- and \pi^0 \pi^0 final states using a subset of the data from the KTeV experiment (E832) at Fermilab. We find that the direct-CP-violation parameter Re(\epsilon'/\epsilon) is…

Owing to the strong suppression of flavour-changing neutral-current transitions in the Standard Model, rare kaon decays constitute a superb tool to constrain hypothetical new-physics interactions. At the same time, they provide many…

We present results for $\varepsilon_K$, the indirect CP violation parameter, calculated in the Standard Model using inputs from lattice QCD: the kaon bag parameter $\hat{B}_K$, and the CKM matrix element $V_{cb}$ from the axial current form…

We present theoretical results for the indirect CP violation parameter, $ |\varepsilon_K| $, evaluated directly within the Standard Model using lattice QCD inputs including $ B_K $, $ |V_{cb}| $, $ |V_{us}| $, $ |V_{ud}| $, $ \xi_0 $, $…

We calculate the new contribution to the direct CP-violation parameter $\epsilon'$ in $K\to \pi\pi$ decay in the minimal left-right symmetric model with the recently-obtained right-handed quark Cabibbo-Kobayashi-Maskawa mixing. We pay…

We reanalyse the ratio $\varepsilon'/\varepsilon$ in the Standard Model (SM) using most recent hadronic matrix elements from the RBC-UKQCD collaboration in combination with most important NNLO QCD corrections to electroweak penguin…

I discuss the comparison of the current theoretical calculations of epsilon'/epsilon with the experimental data. Lacking reliable ``first principle'' calculations, phenomenological approaches may help in understanding correlations among…

We update our 1993 analysis of the CP violating ratio $\epe$ in view of the changes in several input parameters, in particular the improved value of the top quark mass. We also investigate the strange quark mass $m_s$ dependence of $\epe$…

We measure the direct CP-violating parameter A_CP for the decay of the charged charm meson, D+ -> K-pi+pi+ (and charge conjugate), using the full 10.4 fb-1 sample of ppbar collisions at sqrt(s) = 1.96 TeV collected by the D0 detector at the…