Analysis of two-body decays of charm mesons using the quark-diagram scheme

2003

Phys. Rev. D

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The nonleptonic weak decays of charmed mesons into a scalar meson and a pseudoscalar meson are studied. The scalar mesons under consideration are σ [or f 0 (600)], κ, f 0 (980), a 0 (980) and K * 0 (1430). A consistent picture provided by the data suggests that the light scalars below or near 1 GeV form an SU(3) flavor nonet and are predominately the q 2q2 states, while the scalar mesons above 1 GeV can be described as a qq nonet. Hence, we designate q 2q2 to σ, κ, a 0 (980), f 0 (980) and qq to K * 0 . Sizable weak annihilation contributions induced from final-state interactions are essential for understanding the data. Except for the Cabibbo doubly suppressed channel D + → f 0 K + , the data of D → σπ, f 0 π, f 0 K, K * 0 π can be accommodated in the generalized factorization approach. However, the predicted rates for D → a 0 π, a 0 K are too small by one to two orders of magnitude when compared with the preliminary measurements. Whether or not one can differentiate between the two-quark and four-quark pictures for the f 0 (980) produced in the hadronic charm decays depends on the isoscalar f 0 −σ mixing angle in the qq model.

Section: Introductionmentioning

confidence: 99%

Section: Quark Diagram Scheme and Final-state Interactionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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HadronicDdecays involving scalar mesons

2003

Phys. Rev. D

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“…Because a reliable evaluation of hadronic matrix elements is very difficult in general, an alternative approach which is essentially model independent is based on the diagrammatic approach [6][7][8]. In this approach, the topological diagrams are classified according to the topologies of weak interactions with all strong interaction effects included.…”

Section: Introductionmentioning

confidence: 99%

Flavor SU(3) symmetry and QCD factorization in B → PP and PV decays

2011

J. High Energ. Phys.

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Flavor SU(3) symmetry and QCD factorization in B → P P and P V decays AbstractUsing flavor SU(3) symmetry, we perform a model-independent analysis of charmlessB u,d (B s ) → P P, P V decays. All the relevant topological diagrams, including the presumably subleading diagrams, such as the QCD-and EW-penguin exchange diagrams and flavor-singlet weak annihilation ones, are introduced. Indeed, the QCD-penguin exchange diagram turns out to be important in understanding the data for penguin-dominated decay modes. In this work we make efforts to bridge the (model-independent but less quantitative) topological diagram or flavor SU(3) approach and the (quantitative but somewhat model-dependent) QCD factorization (QCDF) approach in these decays, by explicitly showing how to translate each flavor SU(3) amplitude into the corresponding terms in the QCDF framework. After estimating each flavor SU(3) amplitude numerically using QCDF, we discuss various physical consequences, including SU(3) breaking effects and some useful SU(3) relations among decay amplitudes ofB s → P V andB d → P V . *

“…In this diagrammatic sce-nario, all two-body nonleptonic weak decays of heavy mesons can be expressed in terms of six distinct quark diagrams [10,11,12]: T , the color-allowed external W -emission tree diagram; C, the color-suppressed internal W -emission diagram; E, the W -exchange diagram; A, the W -annihilation diagram; P , the horizontal W -loop diagram; and V , the vertical W -loop diagram. (The one-gluon exchange approximation of the P graph is the so-called "penguin diagram".)…”

Section: Introductionmentioning

confidence: 99%

Remarks on the quark content of the scalar mesonf0(1370)

2003

Phys. Rev. D

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Based on the measurements of (D + s , D + ) → f 0 (1370)π + we determine, in a model independent way, the allowed ss content in the scalar meson f 0 (1370). We find that, on the one hand, if this isoscalar resonance is a pure nn state [ nn ≡ (uū + dd)/ √ 2 ], a very large W -annihilation term will be needed to accommodate D + s → f 0 (1370)π + . On the other hand, the ss component of f 0 (1370) should be small enough to avoid excessive D + s → f 0 (1370)π + induced from the external W -emission. Measurement of f 0 (1370) production in the decay D + s → K + K − π + will be useful to test the above picture. For the decay D 0 → f 0 (1370)K 0 which is kinematically barely or even not allowed, depending on the mass of f 0 (1370), we find that the finite width effect of f 0 (1370) plays a crucial role on the resonant three-body decay D 0 → f 0 (1370)K 0 → π + π − K 0 .