The U(1) Problem

Mar, 1975
37 pages
Published in:
  • Phys.Rev.D 11 (1975) 3583-3593
Report number:
  • Print-75-0266 (HARVARD)

Citations per year

197519882001201420250510152025
Abstract: (APS)
A detailed analysis of the problems associated with the conserved U(1) axial-vector current in quark-gluon models is presented. It is shown that such models involve a light isoscalar pseudoscalar boson, with a mass less than 3mπ. The existence of this boson would produce a strong off-shell variation in the η→3π matrix element, thus invalidating the usual conclusions about the rate and energy dependence of this decay. Following Kogut and Susskind, it is proposed that the light Goldstone boson is actually a dipole, with positive- and negative-metric parts, which cancel in matrix elements of gluon-gauge-invariant operators but not in operators such as the U(1) current. It is shown that the masses of the observable pseudoscalar bosons and the η decay rate are then just as they would be in a theory without the U(1) symmetry, and in fair agreement with experiment. The application of current algebra to theories with charmed quarks is briefly discussed.
  • FIELD THEORY: UNIFIED INTERACTION
  • CURRENT ALGEBRA
  • QUARK: CHARM
  • MODEL: GLUON
  • SYMMETRY: U(1)
  • MODEL: CONSERVED A-V CURRENT
  • FIELD THEORY: GOLDSTONE THEOREM
  • FIELD THEORY: OPERATOR ALGEBRA
  • POSTULATED PARTICLE: ISOSCALAR BOSON
  • POSTULATED PARTICLE: PSEUDOSCALAR