Anatomy of $$\varepsilon '/\varepsilon $$ ε ′ / ε beyond the standard model
نویسندگان
چکیده
منابع مشابه
ε′/ε in the Standard Model
providing clear evidence for a non-zero ε/ε value. The theoretical status is instead more debated (see ref. [2] for a brief review). One of the problems that had to be faced during the past years has been that, while CP violation is born at a scale say O(MW ), the observables that enter in the game have to be estimated at a scale of O(MK) (see fig. 1). Changing the order of magnitude of the sca...
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We present a detailed analysis of ε/ε within the Standard Model, taking into account the strong enhancement through final–state interactions identified in refs. [1] and [2]. The relevant hadronic matrix elements are fixed at leading order in the 1/NC expansion, through a matching procedure between the effective short–distance Lagrangian and its corresponding low–energy description in Chiral Per...
متن کاملEstimating ε′/ε in the Standard Model
I discuss the comparison of the current theoretical calculations of ε/ε with the experimental data. Lacking reliable “first principle” calculations, phenomenological approaches may help in understanding correlations among different contributions and available experimental data. In particular, in the chiral quark model approach the same dynamics which underlies the ∆I = 1/2 selection rule in kao...
متن کاملε′/ε in the standard model
In (5), GF is the Fermi coupling, the functions zi(μ) and yi(μ) are the Wilson coefficients and τ = −VtdV ∗ ts/VudV ∗ us. According to the standard parameterization of the CKM matrix, in order to determine ε/ε , we only need to consider the yi(μ) components, which control the CP -violating part of the lagrangian. The coefficients yi(μ), and zi(μ) contain all the dependence of short-distance phy...
متن کاملThe Anatomy of Ε′/ε beyond Leading Logarithms with Improved Hadronic Matrix Elements
Results of a recent calculation of the effective ∆S = 1 Hamiltonian at the next-to-leading order will be presented. These, together with an improved treatment of hadronic matrix elements, are used to evaluate the measure for direct CP-violation, ε/ε, at the next-to-leading order. Taking mt = 130GeV , ΛMS = 300MeV and calculating 〈Q6〉 and 〈Q8〉 in the 1/N approach, we find in the NDR scheme ε/ε =...
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ژورنال
عنوان ژورنال: The European Physical Journal C
سال: 2019
ISSN: 1434-6044,1434-6052
DOI: 10.1140/epjc/s10052-019-6715-6