Diquarks: a QCD sum rule perspective

Abstract

We propose a phenomenological QCD sum rule with an explicit diquark field to investigate the essential ingredients inside the hadrons. Introducing the mass (m_ϕ) and the condensate (ϕ^2) for the diquark field as parameters in the model, we find that the sum rule works well for Lambda, Lambda_c and Lambda_b. This implies that these Lambda baryons can be represented by a diquark and a quark configuration. We also find that there is a duality relation among the parameters (m_ϕ, ϕ^2), for which the sum rule is equally good. In the limit when ϕ^2 =0 we find m_ϕ=0.4 GeV, which can be thought as the constituent diquark mass.

4 pages, 4 figures, revised version published in Phys. Rev. C

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• Evidence for diquarks in lattice QCD
• Stable multiquark states with heavy quarks in a diquark model
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• Sigma meson in pole-dominated QCD sum rules
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• Excitation energy spectra of the Lambda_c and Lambda_b baryons in a finite-size diquark model
• Chiral Structure of Vector and Axial-Vector Tetraquark Currents
• Strong decays of singly heavy baryons from a chiral effective theory of diquarks
• Discussions on Stability of Diquarks
• QCD sum rules for the neutron, $\Sigma$, and $\Lambda$ in neutron matter
• Multiquark correlations in light mesons and baryons from holographic QCD
• Excitation spectra of heavy baryons in diquark models
• Dynamical supersymmetry for strange quark and $ud$ antidiquark in hadron mass spectrum
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• Hadronic few-body systems in chiral dynamics, -- Few-body systems in hadron physics --