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Nonleptonic Two Body Decays of Charmed Mesons. By YU Fusheng ( 于福升 ) 2011 Cross Strait Meeting on Particle Physics and Cosmology. Outline. Introduction phenomenology heavy flavor physics Generalized Factorization Approach Pole Dominance Model Summary. Topological diagrams.
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Nonleptonic Two Body Decays of Charmed Mesons By YU Fusheng (于福升) 2011 Cross Strait Meeting on Particle Physics and Cosmology
Outline • Introduction • phenomenology • heavy flavor physics • Generalized Factorization Approach • Pole Dominance Model • Summary
Introduction • Effective Hamiltonian: basic tool to study the hadronic decay of heavy flavor mesons are Wilson coefficients and are four quark operators:
The amplitude of is • The key is to tackle : • Naïve factorization • Generalized Factorization • Pole dominance model • QCD factorization (QCDF) • Perturbative QCD approach (PQCD) • Soft-collinear effective theory (SCET) • …
Naïve Factorization • Assumption: the matrix element is factorized into two parts, • Neglect the annihilation and nonfactorization contributions
Wilson coefficients for color-favored (T)and color-suppressed (C) processes. • are universal and process independent. • Difficulties: • are renormalization scale and scheme dependent • fail to describe the color-suppressed decay modes due to the smallness of
Generalized Factorization • Consider non-factorization contributions • In the large-Nc approach, • A large relative strong phase between diagrams is induced by final-state interactions
Annihilation contributions • Annihilation diagrams are neglected as an approximation in the factorization model. • We will calculate considerable resonant effects of annihilation diagrams in a single pole dominance model.
Pole Model • Only consider the lowest lying poles • Example:
Pole Model • The weak matrix element is evaluated in the vacuum insertion approximation, • The effective strong coupling • Inserting the propagator of intermediate state, the decay amplitude is
Framework • AnnihilationEmission diagrams • Pole Model Generalized Factorization Approach • Consider relative strong phases between topological diagrams • Calculate the branching ratios of and
Phenomenological Analysis • , large annihilation type contributions agree with the experiment data better than that of the diagrammatic approach.
Largeannihilation type contributions agree with the experiment data. • The single pole resonance effect dominates the annihilation type contribution in most decay modes.
Small annihilation contributions in this model • Due to the smallness of decay constants of intermediate scalar mesons.
Summary • and are studied on the basis • Generalized factorization for emission diagrams • Pole model for resonance effect of annihilation diagrams • Relative strong phases between topological diagrams • Our results agree with experimental data • Annihilation contributions in pole modelsmall to , but largeto
Strong Phase • The amplitudes satisfy the isospin triangle relation but • Besides, importance of inelastic final state interactions of D meson decays in which on-shell intermediate states will contribute imaginary parts.
