Scale invariance and the stability of a hedgehog soliton

Abstract

We show that a scale invariant chiral action proposed not long ago prevents the recently discovered collapse of the hedgehog soliton off the chiral circle calculated with a proper time regularized Nambu-Jona-Lasinio action. The soliton calculated with the scale invariant action turns out to be close to the chiral circle and hence has properties which are very similar to those of the chiral quark loop. Its mass obeys the Ioffe formula.