Sergio Doplicher

Department of Mathematics, "Sapienza" University (Rome, Italy)

Superselection structure in Local Quantum Theories with (neutral) massless particle

Abstract:
Joint work in progress with Detlev Buchholz and John E. Roberts. We study the superselection structure in theories with massless particles which do not carry superselection quantum numbers. The results valid in the massive case do extend, in particular we have the intrinsic notion of particle statistics of superselection sectors, and the existence of a unique compact group dual to the superselection structure. Problems with covariance and spectrum condition remain in the case of non simple sectors (i.e. obeying a parastatistics).