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Volume 334 - The 36th Annual International Symposium on Lattice Field Theory (LATTICE2018) - Hadron Spectroscopy and Interactions
Comparison between models of QCD with and without dynamical charm quarks
S. Cali,* F. Knechtli, T. Korzec
*corresponding author
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Published on: 2019 May 29
We investigate the influence of dynamical charm quarks on observables that depend explicitly on the charm quark fields, like the pseudo-scalar and vector masses $m_{\eta_c}$ and $m_{J/\psi}$, the hyperfine splitting $(m_{J/\psi} − m_{\eta_c} )/m_{\eta_c}$, the charm quark mass and the meson decay constants. For this purpose, instead of working in full QCD we study a simplified setup. We simulate two theories: $N_f = 0$ QCD and QCD with $N_f = 2$ dynamical quarks at the charm mass. The absence of light quarks allows us to reach extremely fine lattice spacings (0.02 fm < a < 0.05 fm) which are crucial for reliable continuum extrapolations. Our main result is a comparison of various quantities in the continuum limit. For the hyperfine splitting we find that the effects of a dynamical charm quark are below our statistical precision of 2%.
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