Paper detail

Diquarks: a QCD sum rule perspective

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.