Skyrme Fun
A while back, I wrote about the possible discovery of an exotic baryon state, , with mass , width and flavour quantum numbers . Truth be told, this was but one of several observations of the same resonance.
What I didn’t say was that this flurry of experimental work was actually the result of a theoretical prediction of the existence of this state on the basis of Skyrme model calculations by Diakonov, Petrov & Polyakov. They found a set of states in the of . By fitting the masses of two of these excitations to the observed N(1710) and (1880) resonances, they predicted that the lightest member of the would be the , with a mass and width (, ) extremely close to the (now) experimentally-observed values.
Recently, Itzhaki, Klebanov, Ouyang, and Rastelli have looked a little more closely at the large- Skyrme Model. They argue that, in the “bound state” approach of Callan & Klebanov (Nucl. Phys. B262 (1985) 365), this resonance does not appear — unless you do something rather artificial, like crank up the SU(3) symmetry-breaking ().
I don’t know what to make of this. Diakonov et al’s “rigid rotator” approximation results at are way too good to be dismissed out-of-hand. It would be sad if there weren’t a clean way to derive them from large-.
Posted by distler at October 8, 2003 12:40 AM