A renormalization group flow equation with a scale-dependent transformation of field variables gives a unified description of fundamental and composite degrees of freedom. In the context of the effective average action, we study the renormalization flow of scalar bound states which are formed out of fundamental fermions. We use the gauged Nambu-Jona-Lasinio model at weak gauge coupling as an example. Thereby, the notions of a bound state or fundamental particle become scale dependent, being classified by the fixed-point structure of the flow of effective couplings.
Physical Review D
- Pub Date:
- March 2002
- Renormalization group evolution of parameters;
- High Energy Physics - Theory;
- High Energy Physics - Phenomenology
- 25 pages, 3 figures, v2: minor corrections, version to appear in PRD