منابع مشابه
Kl3 decays in Chiral Perturbation Theory
The process Kl3 is calculated to two-loop order (p 6) in Chiral Perturbation Theory (ChPT) in the isospin conserved case. We present expressions suitable for use with previous work in two-loop CHPT where the order p4 parameters (Li ) were determined from experiment. We point out that all the order p6 parameters (C i ) that appear in the value of f+(0) relevant for the determination of |Vus| can...
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We present the matrix elements for the semileptonic kaon decays Kl2γ , Kl2l+l−, Kl2l′+l′−, Kl3, Kl3γ and Kl4 at next-to-leading order in chiral perturbation theory and compare the predictions with experimental data. Monte Carlo event generators are used to calculate the corresponding rates at DAFNE. We discuss the possibilities to improve our knowledge of the low-energy structure of the Standar...
متن کاملHyperon Decays in Chiral Perturbation Theory Revisited
The discrepancies found between S-wave and P-wave fits for hyperon decays are reinvestigated using the heavy baryon chiral Lagrangian formalism. The agreement is found to improve through the inclusion of previously omitted diagrams. The S-waves are unaffected by this, but the P-wave predictions are modified. A correlated fit to the chiral parameters is performed and the results discussed.
متن کاملtau decays and chiral perturbation theory.
In a small window of phase space, chiral perturbation theory can be used to make standard model predictions for tau decays into two and three pions. For τ → 2πντ , we give the analytical result for the relevant form factor FV up to two loops, then calculate the differential spectrum and compare with available data. For τ → 3πντ , we have calculated the hadronic matrix element to one loop. We di...
متن کاملTest of Chiral Perturbation Theory in kaon decays
This paper presents results obtained by the CERN experiment NA48/2. Sample of 7146 K → πee decays, of 1164 K → πγγ events and of 120 K → πγee events have been collected with small background contamination. Branching ratio and form factors for three different models have been obtained for K → πee, plus a model-independent branching ratio. In addition, the first measurement of the direct CP viola...
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ژورنال
عنوان ژورنال: Nuclear Physics B
سال: 2003
ISSN: 0550-3213
DOI: 10.1016/s0550-3213(03)00581-9