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

Abstract

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 themore » 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.« less

Authors:
;  [1];  [2]
  1. Institute of Physics, Academia Sinica, Taipei, Taiwan 115 (China)
  2. Department of Physics, Chung Yuan Christian University, Chung-Li, Taiwan 320 (China)
Publication Date:
OSTI Identifier:
20774602
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevD.73.014017; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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

Citation Formats

Cheng Haiyang, Chua Chunkhiang, and Yang Kweichou. Charmless hadronic B decays involving scalar mesons: Implications on the nature of light scalar mesons. United States: N. p., 2006. Web. doi:10.1103/PhysRevD.73.014017.
Cheng Haiyang, Chua Chunkhiang, & Yang Kweichou. Charmless hadronic B decays involving scalar mesons: Implications on the nature of light scalar mesons. United States. doi:10.1103/PhysRevD.73.014017.
Cheng Haiyang, Chua Chunkhiang, and Yang Kweichou. Sun . "Charmless hadronic B decays involving scalar mesons: Implications on the nature of light scalar mesons". United States. doi:10.1103/PhysRevD.73.014017.
@article{osti_20774602,
title = {Charmless hadronic B decays involving scalar mesons: Implications on the nature of light scalar mesons},
author = {Cheng Haiyang and Chua Chunkhiang and Yang Kweichou},
abstractNote = {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.},
doi = {10.1103/PhysRevD.73.014017},
journal = {Physical Review. D, Particles Fields},
number = 1,
volume = 73,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • The scalar productions in heavy meson decays can provide a good platform to study not only heavy flavor physics but also their own physical properties in a dramatically different way. In this work, based on the assumption of two-quark structure of the scalars, the charmless hadronic B{sub c}{yields}SP,SV decays (here, S, P, and V denote the light scalar, pseudoscalar, and vector mesons, respectively) are investigated by employing the perturbative QCD (pQCD) factorization approach. In the standard model all these considered B{sub c} meson decays can only occur through the annihilation diagrams. From our numerical evaluations and phenomenological analysis, we findmore » that (a) the pQCD predictions for the CP-averaged branching ratios (BRs) of the considered B{sub c} decays vary in the range of 10{sup -5} to 10{sup -8}, which will be tested in the ongoing LHCb and forthcoming Super-B experiments, while the CP-violating asymmetries for these modes are absent naturally in the standard model because only one type tree operator is involved; (b) for B{sub c}{yields}SP,SV decays, the BRs of {Delta}S=0 processes are basically much larger than those of {Delta}S=1 as generally expected because the different Cabibbo-Kobayashi-Maskawa factors are involved; (c) analogous to B{yields}K{sup *{eta}(')} decays, Br(B{sub c}{yields}{kappa}{sup +}{eta}){approx}5xBr(B{sub c}{yields}{kappa}{sup +}{eta}') in the pQCD approach, which can be understood by the constructive and destructive interference between the {eta}{sub q} and {eta}{sub s} contributions to the B{sub c}{yields}{kappa}{sup +}{eta} and B{sub c}{yields}{kappa}{sup +}{eta}' decays, however, Br(B{sub c}{yields}K{sub 0}{sup *}(1430){eta}) is approximately equal to Br(B{sub c}{yields}K{sub 0}{sup *}(1430){eta}{sup '}) in both scenarios because the factorizable contributions from the {eta}{sub s} term play the dominant role in the considered two channels; (d) if a{sub 0}(980) and {kappa} are the qq bound states, the pQCD predicted BRs for B{sub c}{yields}a{sub 0}(980)({pi},{rho}) and B{sub c}{yields}{kappa}K{sup (*)} decays will be in the range of 10{sup -6{approx}}10{sup -5}, which are within the reach of the LHCb experiments and could be measured in the near future; and (e) for the a{sub 0}(1450) and K{sub 0}{sup *}(1430) channels, the BRs for B{sub c}{yields}a{sub 0}(1450)({pi},{rho}) and B{sub c}{yields}K{sub 0}{sup *}(1430)K{sup (*)} modes in the pQCD approach are found to be (5{approx}47)x10{sup -6} and (0.7-36)x10{sup -6}, respectively. A measurement of them at the predicted level will favor the qq structure and help understand the physical properties of the scalars and the involved QCD dynamics in the modes, especially the reliability of the pQCD approach to these B{sub c} meson decays.« less
  • No abstract prepared.
  • Based on a sample of approximately 500 000 hadronic Z{sup 0} decays accumulated between 1993 and 1998, the SLD experiment has set limits on 24 fully charged two-body and quasi-two-body exclusive charmless hadronic decays of B{sup +}, B{sup 0}, and B{sub s}{sup 0} mesons. The precise tracking capabilities of the SLD detector provided for the efficient reduction of combinatoric backgrounds, yielding the most precise available limits for ten of these modes. (c) 2000 The American Physical Society.
  • We present an overview of branching ratio and direct CP asymmetry measurements for charmless b-hadron decays into two-body hadronic final states using 180 pb-1 of data collected by the CDF II experiment at the Fermilab Tevatron collider. The following modes are treated: B{sub d,s}{sup 0}{yields}h{sup +}h'{sup -}, {lambda}{sub b}{sup 0}{yields}ph{sup -}, where h and h' stand for K or {pi}, B{sub u}{sup +}{yields}{phi}K{sup +}, and B{sub s}{sup 0}{yields}{phi}{phi}.
  • The nonleptonic weak decays of meson B into a scalar and pseudoscalar meson are studied. The scalar mesons under consideration are {sigma} (or f0(600)), f0(980), a0(980) and K{sub 0}{sup *}(1430). We calculate the Branching ratios in the Naive Factorization approximation. Scalars are assumed to be qq-bar bounded sates, but an estimation can be obtained in the case they are four bounded states.