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arXiv · 1902.03808

Meson Electromagnetic Form Factors from Lattice QCD

C. T. H. Davies·J. Koponen·G. P. Lepage·A. T. Lytle·A. C. Zimermmane-Santos
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Abstract

Lattice QCD can provide a direct determination of meson electromagnetic form factors, making predictions for upcoming experiments at Jefferson Lab. The form factors are a reflection of the bound-state nature of the meson and so these calculations give information about how confinement by QCD affects meson internal structure. The region of high squared (space-like) momentum-transfer, $Q^2$, is of particular interest because perturbative QCD predictions take a simple form in that limit that depends on the meson decay constant. We previously showed in\cite{jonnaff} that, up to $Q^2$ of 6 $\mathrm{GeV}^2$, the form factor for a `pseudo-pion' made of strange quarks was significantly larger than the asymptotic perturbative QCD result and showed no sign of heading towards that value at higher $Q^2$. Here we give predictions for real mesons, the $K^+$ and $K^0$, in anticipation of JLAB results for the $K^+$ in the next few years. We also give results for a heavier meson, the $\eta_c$, up to $Q^2$ of 25 $\mathrm{GeV}^2$ for a comparison to perturbative QCD in a higher $Q^2$ regime.

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C. T. H. Davies, J. Koponen, G. P. Lepage, A. T. Lytle, A. C. Zimermmane-Santos. 2019-02-11. Meson Electromagnetic Form Factors from Lattice QCD. https://arxiv.org/abs/1902.03808

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