Colour chiral solitons in low energy QCD

Abstract

We derive an effective colour chiral action with a background gauge field. The action describes configurations of soliton-skyrmion type. Kinetic term constant $f_0^2$, analogue of $f_\pi ^2$, is a phenomenological dimensional parameter of the model; $d=4$ terms are unique up to the choice of background gauge field. The case of SU(2) colour group is discussed in detail. We study an isolated configuration, i.e. a configuration in a background field which is the vacuum field forming the gluon condensate. Thereby we introduce the condensate energy as a second parameter and scale. Compared with the case of flavor skyrmion configuration, the colour chiral action contains a piece with slowly decreasing terms coming from the background vacuum field. Asymptotic behaviour at large distances shows exponential decrease for the case of chromomagnetic condensates and periodic otherwise . This defines a stability region for a colour soliton. The mass is given by the positive definite integrand for a soliton of purely bosonization origin. Contribution from the Yang-Mills action of the background colour field has the sign opposite to bosonization part. The baryon number current is not influenced by the background field and leads to the standard baryon number $B=N_F/N_C$ . For $B=1/3$ we evaluated the estimate from above $M\approx 460$ $Mev$ .