We propose a phenomenological QCD sum rule with an explicit diquark field to investigate the essential ingredients inside the hadrons. By introducing the mass mφ and the condensate φ2 for the diquark field as parameters in the model, we find that the sum rule works well for Λ, Λc, and Λb. This implies that these Λ baryons can be represented by a diquark and a quark configuration. We also find that there is a duality relation among the parameters (mφ, φ2) for which the sum rule is equally good. In the limit when φ=0, we find mφ=400 MeV, which can be thought of as the constituent diquark mass.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics