Two Photon Decays of ${\eta }_c$ from Lattice QCD

Abstract

We present an exploratory lattice study for the two-photon decay of ${\eta }_c$ using $N_f=2$ twisted mass lattice QCD gauge configurations generated by the European Twisted Mass Collaboration. Two different lattice spacings of $a=0.067$fm and $a=0.085$fm are used in the study, both of which are of physical size of 2$fm$. The decay widths are found to be $1.025(5)$KeV for the coarser lattice and $1.062(5)$KeV for the finer lattice respectively where the errors are purely statistical. A naive extrapolation towards the continuum limit yields $\Gamma \simeq 1.122(14)$KeV which is smaller than the previous quenched result and most of the current experimental results. Possible reasons are discussed.

arXiv comment13 pages, 7 figures; matches the published version

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Cited by in corpus (16)

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• Precise determination of decay rates for ${\eta }_c\to \gamma \gamma$, $J/\psi \to \gamma {\eta }_c$ and $J/\psi \to {\eta }_c{e}^{+}{e}^{-}$ from lattice QCD
• Pion to photon transition form factors with basis light-front quantization
• Two-photon transitions of charmonia on the light front
• The ${\gamma }^{\ast }{\gamma }^{\ast }\to {\eta }_c(1S,2S)$ transition form factors for spacelike photons
• The Glueball content of ${\eta }_c$
• First-principle calculation of ${\eta }_c\to 2\gamma$ decay width from lattice QCD
• Systematic twist expansion of $({\eta }_c,{\eta }_b)\to {\gamma }^{\ast }\gamma$ transition form factors in light-front quark model
• Ward Identity of the Vector Current and the Decay Rate of ${\eta }_c\to \gamma \gamma$ in Lattice QCD
• A Lattice Study of the Two-photon Decay Widths for Scalar and Pseudo-scalar Charmonium
• Three Photon Decay of $J/\psi$ from Lattice QCD
• Observation of the charmonium decay ${\eta }_c\to \gamma \gamma$ in $J/\psi \to \gamma {\eta }_c$
• Self-consistent analysis for the ${\eta }_c\to \gamma \gamma$ process
• Study of the Magnetic Dipole Transition of $J/\psi \to \gamma {\eta }_c$ via ${\eta }_c\to p\bar{p}$