Implications of color gauge symmetry for nucleon spin structure

Aug, 1998
8 pages
Published in:
  • Phys.Rev.D 59 (1999) 074010
e-Print:
Report number:
  • UMD-PP-99-012,
  • DOE-ER-40762-158

Citations per year

1998200420102016202002468
Abstract:
We study the chromodynamical gauge symmetry in relation to the internal spin structure of the nucleon. We show that 1) even in the helicity eigenstates the gauge-dependent spin and orbital angular momentum operators do not have gauge-independent matrix element; 2) the evolution equations for the gluon spin take very different forms in the Feynman and axial gauges, but yield the same leading behavior in the asymptotic limit; 3) the complete evolution of the gauge-dependent orbital angular momenta appears intractable in the light-cone gauge. We define a new gluon orbital angular momentum distribution Lg(x)L_g(x) which {\it is} an experimental observable and has a simple scale evolution. However, its physical interpretation makes sense only in the light-cone gauge just like the gluon helicity distribution Δg(x)\Delta g(x)y.
  • nucleon: spin
  • quantum chromodynamics
  • invariance: gauge
  • helicity
  • spin: orbit
  • angular momentum
  • gluon: spin
  • transformation: gauge
  • light cone