Double scaling limit of N=2 chiral correlators with Maldacena-Wilson loop

Abstract

We consider $\mathcal N=2$ conformal QCD in four dimensions and the one-point correlator of a class of chiral primaries with the circular $\frac{1}{2}$-BPS Maldacena-Wilson loop. We analyze a recently introduced double scaling limit where the gauge coupling is weak while the R-charge of the chiral primary $Φ$ is large. In particular, we consider the case $Φ=(\text{tr}φ^{2})^{n}$ , where $φ$ is the complex scalar in the vector multiplet. The correlator defines a non-trivial scaling function at fixed $κ= n\,g_{\rm YM}^{2}$ and large $n$ that may be studied by localization. For any gauge group $SU(N)$ we provide the analytic expression of the first correction $\sim ζ(3)\,κ^{2}$ and prove its universality. In the $SU(2)$ and $SU(3)$ theories we compute the scaling functions at order $\mathcal O(κ^{6})$. Remarkably, in the $SU(2)$ case the scaling function is equal to an analogous quantity describing the chiral 2-point functions $\langleΦ\overlineΦ\rangle$ in the same large R-charge limit. We conjecture that this $SU(2)$ scaling function is computed at all-orders by a $\mathcal N=4$ SYM expectation value of a matrix model object characterizing the one-loop contribution to the 4-sphere partition function. The conjecture provides an explicit series expansion for the scaling function and is checked at order $\mathcal O(κ^{10})$ by showing agreement with the available data in the sector of chiral 2-point functions.