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RENCONTRES DE MORIOND March 2005. Rare Decays. David GREYNAT. in collaboration with S. FRIOT and E. de RAFAEL. arXiv:hep-ph/0404136 or PLB 595 (2004) 301. Motivations. 1- New experimental results for the rare decays. [NA48 ’03]. Those results allow for a.
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RENCONTRES DE MORIOND March 2005 Rare Decays David GREYNAT in collaboration with S. FRIOT and E. de RAFAEL arXiv:hep-ph/0404136 or PLB 595 (2004) 301
Motivations 1- New experimental results for the rare decays [NA48 ’03] Those results allow for a Re-analysis of the CP violating rare decay 2- Computation of some of the coupling constants of the effective to leading and next-to-leading orders in Large NC QCD
CP Direct Short Distance Contribution CP indirect directly from CP Conservingpart CP Violating part Constructive ? InterferenceTerm Destructive
which can be rewritten in a more convenient way (Large NC counting) is where is Experimental constraints on this coupling constants via Chiral Lagrangians The nature of the interference is strongly linked to coupling constants of chiral Lagrangians Precisely to and in their combination In fact the usual chiral electro-weak order p4 Lagrangian is[EPdeR ’87]
[PDG ’02] [NA48 ’03] Constraints from Branching Ratios Key-quantities Order p4
Octet Dominance Hypothesis and Large-NC Predictions OctetDominanceHypothesis[EPdR ‘87]: Large-NcPredictions : Through the bosonization of the factorized part of the operator matched to O(p4) chiral Lagrangian gives See also [Bruno Prades ’93]
Results Conclusion: in both cases thenCONSTRUCTIVE INTERFERENCE But the sign of is not clearly predicted: Need for a Large NC next-to-leading order calculation
Order p4: where is given by the pion chiral loop. Clearly, the O(p4) is not sufficient Constraints from the form factor
Beyond order p4 Strategies: Guess of dominantO(p6 ) contributions [Isidori et al. ’03] • O(p4 )+ Chiral resummation (inspired by M.H.A of Large NC) « NarrowResonance Minimal Structure »
Narrow resonances dynamical framework K K K K NRD Hyp. MHA chiral limit In agreement with Octet Dominance assumption [EPdeR ’87]
Minimal Narrow Resonances Saturation of the Form Factor The form factor is now
Prediction for CP Conserving Part[Buchalla et al. ‘03] CP Direct Violating Part[Buchalla et al. ‘03] CP Indirect Violating Part[NA48 ‘03] Interference term[this work]
Conclusions and Outlook • This analysis which combined chiral perturbation theory at order p4 with a model inspired by Large NC gives very good results for the known branching ratios of • We obtain a prediction for the golden mode closed to reachable experimental determination • Next-to-leading order calculation in Large-NC QCD of In the framework of [Hambye et al. ’03]