Abstract: |
I will discuss some properties of baryons in the Sakai-Sugimoto model, which is the gravity dual of a QCD-like theory. In this theory baryons appear as soliton solutions, which are usually approximated as flat-space instantons in computations of baryon properties in the model. But there was a puzzle: it turns out that with that approximation, which is motivated by the large 't Hooft coupling limit implicit in the model, one does not reproduce some model-independent predictions for baryon form factors which are connected with long-range pion physics. This made it appear that the long-range pion physics of baryons may be hidden in (intractable) \alpha' corrections in the gravity dual. This would be somewhat surprising if true. I will report some recent partial progress in understanding the puzzle, based on a new approach to the study of baryons in the model which does not call on the flat-space instanton approximation. The solutions we obtained give the correct result for the model-independent predictions, with the happy implication that the Sakai-Sugimoto model captures the expected infrared properties of baryons without the need to include effects from beyond the leading order in the \alpha' expansion. |