منابع مشابه
Γγ and Unitarity *
Agreement between the experimental value Γ(KS → γγ) and the number predicted via a one-loop chiral perturbation theory calculation has been cited as a success for the latter. On the other hand the one-loop prediction for the closely related process KL → π0γγ has been found to be a factor three below the experimental value. Using the inputs of unitarity and dispersion relations, we demonstrate t...
متن کاملStrangeness and Unitarity
The strange-quark vector current form factors of the nucleon are analyzed within the framework of dispersion relations. Particular attention is paid to contributions made by KK̄ intermediate states to the form factor spectral functions. It is shown that, when the KK̄ → NN̄ amplitude is evaluated in the Born approximation, the KK̄ contributions are identical to those arising from a one-loop calculat...
متن کاملAnd Ckm Unitarity
The Cabibbo-Kobayashi-Maskawa (CKM) [1,2] three-generation quark mixing matrix written in terms of the Wolfen-stein parameters (λ, A, ρ, η) [3] nicely illustrates the orthonor-mality constraint of unitarity and central role played by λ. V CKM = ⎛ ⎝ V ud V us V ub V cd V cs V cb V td V ts V tb ⎞ ⎠ = ⎛ ⎝ 1 − λ 2 /2 λ Aλ 3 (ρ − iη) −λ 1 − λ 2 /2 Aλ 2 Aλ 3 (1 − ρ − iη) −Aλ 2 1 ⎞ ⎠ +O(λ 4). (1) That...
متن کاملRadiative Kaon Decays and the Penguin Contribution to the ∆i = 1/2 Rule
A consistent census of penguins in the ∆I = 1/2 rule is taken from the η0 pole contribution to the radiative KL → γγ, KS → π0γγ and K+ → π+γγ decay modes. We briefly comment on its impact for KL → π0π0γγ, KL → π+π−γ and check its compatibility with the KL−KS mass difference and the CP violating ε′/ε parameter.
متن کاملHiggsless fermion masses and unitarity
We discuss the consistency of fermion mass generation by boundary conditions and brane localized terms in higher dimensional Higgsless models of gauge symmetry breaking. The sum rules imposed by tree-level unitarity and Ward Identities are applied to check the consistency of mass generation by orbifold projections and more general boundary conditions consistent with the variational principle. W...
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ژورنال
عنوان ژورنال: Physics Letters B
سال: 1993
ISSN: 0370-2693
DOI: 10.1016/0370-2693(93)90307-4