6533b827fe1ef96bd128647d

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Topological susceptibility and η′ meson mass from Nf=2 lattice QCD at the physical point

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In this paper we explore the computation of topological susceptibility and ${\ensuremath{\eta}}^{\ensuremath{'}}$ meson mass in ${N}_{f}=2$ flavor QCD using lattice techniques with a physical value of the pion mass as well as larger pion mass values. We observe that the physical point can be reached without a significant increase in the statistical noise. The mass of the ${\ensuremath{\eta}}^{\ensuremath{'}}$ meson can be obtained from both fermionic two point functions and topological charge density correlation functions, giving compatible results. With the pion mass dependence of the ${\ensuremath{\eta}}^{\ensuremath{'}}$ mass being flat we arrive at ${M}_{{\ensuremath{\eta}}^{\ensuremath{'}}}=772(18)\text{ }\text{ }\mathrm{MeV}$ without an explicit continuum limit. For the topological susceptibility we observe a linear dependence on ${M}_{\ensuremath{\pi}}^{2}$, however, with an additional constant stemming from lattice artifacts.