Topological susceptibility of QCD with dynamical M\"obius domain wall fermions

We compute the topological susceptibility ${\chi }_t$ of lattice QCD with $2+1$ dynamical quark flavors described by the M"obius domain wall fermion. Violation of chiral symmetry as measured by the residual mass is kept at $\sim$1 MeV or smaller. We measure the fluctuation of the topological charge density in a `slab’ sub-volume of the simulated lattice using the method proposed by Bietenholz {\it et al.} The quark mass dependence of ${\chi }_t$ is consistent with the prediction of chiral perturbation theory, from which the chiral condensate is extracted as $\Sigma^{\overline{\rm MS}} (\mbox{2GeV}) = [274(13)(29)\mbox{MeV}]^3$, where the first error is statistical and the second one is systematic. Combining the results for the pion mass $M_{\pi }$ and decay constant $F_{\pi }$, we obtain ${\chi }_t=0.229(03)(13)M_{\pi }^2{F}_{\pi }^2$ at the physical point.