Dynamics of effective gluons
Abstract
Renormalized Hamiltonians for gluons are constructed using a perturbative boostinvariant renormalization group procedure for effective particles in lightfront QCD, including terms up to third order. The effective gluons and their Hamiltonians depend on the renormalization group parameter λ, which defines the width of momentumspace form factors that appear in the renormalized Hamiltonian vertices. Thirdorder corrections to the threegluon vertex exhibit asymptotic freedom, but the rate of change of the vertex with λ depends in a finite way on regularization of smallx singularities. This dependence is shown in some examples, and a class of regularizations with two distinct scales in x is found to lead to the Hamiltonian running coupling constant whose dependence on λ matches the known perturbative result from Lagrangian calculus for the dependence of gluon threepoint Green's function on the running momentum scale at large scales. In the Fockspace basis of effective gluons with small λ, the vertex form factors suppress interactions with large kinetic energy changes and thus remove direct couplings of lowenergy constituents to highenergy components in the effective boundstate dynamics. This structure is reminiscent of parton and constituent models of hadrons.
 Publication:

Physical Review D
 Pub Date:
 June 2001
 DOI:
 10.1103/PhysRevD.63.116006
 arXiv:
 arXiv:hepth/0012012
 Bibcode:
 2001PhRvD..63k6006G
 Keywords:

 11.10.Gh;
 11.15.q;
 12.38.Lg;
 Renormalization;
 Gauge field theories;
 Other nonperturbative calculations;
 High Energy Physics  Theory
 EPrint:
 29 pages, plain LaTeX, 1 Postscript figure