Extended chiral Group and Scalar Diquarks

الأصل · EN

We introduce extended chiral transformation, which depends both on pseudoscalar and diquark fields as parameters and determine its group structure. Assuming soft symmetry breaking in diquark sector, bosonisation of a quasi-Goldstone ud-diquark is performed. In the chiral limit the ud-diquark mass is defined by the gluon condensate, mud≈ 300 MeV. The diquark charge radius is <r²ud>¹/²≈ 0.5 fm. We consider also the flavour triplet of scalar diquarks (ud), (us) and (ds) together with pseudoscalar mesons and calculate diquark masses and decay constants in terms of meson parameters and the gluon condensate.