Mehen, T; Stewart, IW; Wise, MB, *Wigner symmetry in the limit of large scattering lengths*,
Physical Review Letters, vol. 83 no. 5
(1999),
pp. 931-934 .
**Abstract:**

*We note that, in the limit where the NN 1S0 and 3S1 scattering lengths, a(1S0) and a(3S1), go to infinity, the leading terms in the effective field theory for strong NN interactions are invariant under Wigner's SU(4) spin-isospin symmetry. This explains why the leading effects of radiation pions on the S-wave NN scattering amplitudes vanish as a(1S0) and a(3S1) go to infinity. The implications of Wigner symmetry for NN → NN axion and γd → np are also considered. © 1999 The American Physical Society.*