No Spontaneous Breakdown of Chiral Symmetry in Nambu-Jona-Lasinio Model

Abstract

We argue that the spontaneous breakdown of symmetry in the chirally symmetric Nambu--Jona-Lasinio model which was supposed to illustrate the origin of the low mass of pions in hadron physics does not occur due to strong fluctuations in the sigma - pi field space. Although quarks acquire a constituent mass, sigma and pi turn out to have equal heavy masses of the order of the constituent quark mass.

Comments: Contains a number of improvements. Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper also at http://www.physik.fu-berlin.de/~kleinert/291