Long-distance properties of baryons in the Sakai-Sugimoto model

Abstract

We reconsider the realization of baryons in the Sakai-Sugimoto model. In this theory, which is the gravity dual of a QCD-like theory, baryons appear as soliton solutions. These solitons were approximated as flat-space instantons in previous studies. However, with this approximation, it has been shown that one does not reproduce some model-independent predictions for the behavior of baryon electromagnetic 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. In this paper, we study the long-range properties of baryons in the Sakai-Sugimoto model without relying on the flat-space instanton approximation. The solution we obtain gives the correct result for the model-independent ratio of form factors, implying that the model captures the expected infrared properties of baryons without the need to go beyond the leading order in the \alpha' expansion.

Comments: 23 pages, 1 figure. v2: reference added