2010/05/31 by Gadde, Abhijit, Pomoni, Elli, Rastelli, Leonardo · 1 citation
#FOS: Physical sciences #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.1006.0015
In this paper we find preliminary evidence that N=2 superconformal QCD, the SU(Nc) SYM theory with Nf= 2 Nc fundamental hypermultiplets, might be integrable in the large N Veneziano limit. We evaluate the one-loop dilation operator in the scalar sector of the N=2 superconformal quiver with SU(Nc) X SU(N\check c) gauge group, for Nc = N\check c. Both gauge couplings g and \check g are exactly marginal. This theory interpolates between the Z2 orbifold of N=4 SYM, which corresponds to \check g=g, and N=2 superconformal QCD, which is obtained for \check g -> 0. The planar one-loop dilation operator takes the form of a nearest-neighbor spin-chain Hamiltonian. For superconformal QCD the spin chain is of novel form: besides the color-adjoint fields ϕab, which occupy individual sites of the chain, there are "dimers" Qai Qib of flavor-contracted fundamental fields, which occupy two neighboring sites. We solve the two-body scattering problem of magnon excitations and study the spectrum of bound states, for general \check g/g. The dimeric excitations of superconformal QCD are seen to arise smoothly for \check g -> 0 as the limit of bound wavefunctions of the interpolating theory. Finally we check the Yang-Baxter equation for the two-magnon S-matrix. It holds as expected at the orbifold point \check g = g. While violated for general \check g ≠ g, it holds again in the limit \check g -> 0, hinting at one-loop integrability of planar N=2 superconformal QCD.