1994/12/20 by Steven Weinberg · 1 voice
Physics and Astronomy · #Amplitude #Chiral anomaly #Current algebra #Field theory (psychology) #High-Energy Particle Collisions Research #Lagrangian #Nuclear physics research studies #Nucleon #Pion #Quantum Chromodynamics and Particle Interactions #Symmetry (geometry) #Term (time) #Tower #hep-ph
paper · pdf · doi:10.1007/3-540-59279-2_61
19 pages, plain LaTeX, no macros needed
arxiv created 1994/12/20 · openalex publication_date 2008/04/06 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
This is a revised version of a talk given at the Chiral Dynamics Workshop at M.I.T., July 25, 1994. It reports results in three areas: (1) The isospin-violating interactions between one non-relativistic nucleon and any number of soft pions can be summarized in a single term in the effective chiral Lagrangian, with no unknown parameters. (2) With D'Hoker, it has been shown that the terms in the Lagrangian for an effective field theory with symmetry G spontaneously broken to H, that are not the integrals of G-invariant Lagrangian densities, are in one-to-one correspondence with the generators of H5(G/H,R). (3) If we assume that the nucleon is connected by successive one-pion transitions only to a tower of narrow baryon states with T=J=1/2,3/2,…,Nc/2, then the Adler-Weisberger and superconvergence relations tell us (for any Nc) that (a) the tower states are degenerate, and (b) the one-pion transition amplitudes between these states generate the \em uncontracted algebra of SU(4)× O(3).