Is SU(2) x SU(2) a better symmetry than SU(3)?

1970
10 pages
Published in:
  • Phys.Rev.Lett. 26 (1971) 594

Citations per year

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Abstract: (APS)
Using the πN phase shifts and fixed-t dispersion relations we have calculated (to first order in symmetry breaking) the nucleon matrix element of the current algebra "sigma" term, and found a value of about 110 MeV. This is an order of magnitude larger than the prediction of the (3,3*)⊕(3*,3) model for chiral symmetry breaking and it indicates that SU(2)⊗SU(2) breaking is comparable to SU(3) breaking.