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arXiv · hep-ph/9910396

A New Approach to Weak Amplitudes in Large-Nc QCD

M. Knecht·S. Peris·E. de Rafael·.
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Abstract

We report on some recent progress made in understanding weak matrix elements of mesons in the context of the next-to-leading order of the large-Nc approximation to QCD. Specifically, we first use the example of the weak contributions to the pi^+ - pi^0 mass difference to exhibit how a systematic matching can be achieved analytically between short distances and long distances within our large-Nc framework. We are then also able to compute matrix elements of the operator Q_7, as they turn out to depend on the same QCD correlator as the previous pion mass difference. As a final example we determine the chiral counterterms governing the pseudoscalar decay into a lepton pair, where we briefly comment also on the special case K_L -> mu^+ mu^-.

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M. Knecht, S. Peris, E. de Rafael, .. 1999-10-19. A New Approach to Weak Amplitudes in Large-Nc QCD. https://doi.org/10.1016/s0920-5632(00)00577-6

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