Charmless hadronic B decays involving scalar mesons: Implications on the nature of light scalar mesons

Journal Article · Sun Jan 01 00:00:00 EST 2006 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.73.014017· OSTI ID:20774602

Haiyang, Cheng; Chunkhiang, Chua ^[1]; Kweichou, Yang ^[2]

---

1. Institute of Physics, Academia Sinica, Taipei, Taiwan 115 (China)
2. Department of Physics, Chung Yuan Christian University, Chung-Li, Taiwan 320 (China)

The hadronic charmless B decays into a scalar meson and a pseudoscalar meson are studied within the framework of QCD factorization. Based on the QCD sum rule method, we have derived the leading-twist light-cone distribution amplitudes of scalar mesons and their decay constants. Although the light scalar mesons f{sub 0}(980) and a{sub 0}(980) are widely perceived as primarily the four-quark bound states, in practice it is difficult to make quantitative predictions based on the four-quark picture for light scalars. Hence, predictions are made in the 2-quark model for the scalar mesons. The short-distance approach suffices to explain the observed large rates of f{sub 0}(980)K{sup -} and f{sub 0}(980)K{sup 0} that receive major penguin contributions from the b{yields}sss process. When f{sub 0}(980) is assigned as a four-quark bound state, there exist extra diagrams contributing to B{yields}f{sub 0}(980)K. Therefore, a priori the f{sub 0}(980)K rate is not necessarily suppressed for a four-quark state f{sub 0}(980). The predicted B{sup 0}{yields}a{sub 0}{sup {+-}}(980){pi}{sup {+-}} and a{sub 0}{sup +}(980)K{sup -} rates exceed the current experimental limits, favoring a four-quark nature for a{sub 0}(980). The penguin-dominated modes a{sub 0}(980)K and a{sub 0}(1450)K receive predominant weak annihilation contributions. There exists a twofold experimental ambiguity in extracting the branching ratio of B{sup -}{yields}K{sub 0}*{sup 0}(1430){pi}{sup -}, which can be resolved by measuring other K{sub 0}*(1430){pi} modes in conjunction with the isospin symmetry consideration. Large weak annihilation contributions are needed to explain the K{sub 0}*(1430){pi} data. The decay B{sup 0}{yields}{kappa}{sup +}K{sup -} provides a nice ground for testing the 4-quark and 2-quark nature of the {kappa} meson. It can proceed through W-exchange and hence is quite suppressed if {kappa} is made of two quarks, while it receives a tree contribution if {kappa} is predominately a four-quark state. Hence, an observation of this channel at the level of > or approx. 10{sup -7} may imply a four-quark assignment for the {kappa}. Mixing-induced CP asymmetries in penguin-dominated modes are studied and their deviations from sin2{beta} are found to be tiny.

• OSTI ID: 20774602
• Journal Information: Physical Review. D, Particles Fields, Vol. 73, Issue 1; Other Information: DOI: 10.1103/PhysRevD.73.014017; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
A0-980 MESONS
AMPLITUDES
ANNIHILATION
ASYMMETRY
B MESONS
BOUND STATE
BRANCHING RATIO
CP INVARIANCE
DISTANCE
DISTRIBUTION
F0-980 MESONS
FACTORIZATION
FEYNMAN DIAGRAM
HADRONIC PARTICLE DECAY
ISOSPIN
KAONS NEUTRAL
LIGHT CONE
PERIPHERAL MODELS
PIONS MINUS
PIONS PLUS
QUANTUM CHROMODYNAMICS
QUARK MODEL
QUARKS
SCALARS
SUM RULES
SYMMETRY