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arXiv · 1602.00076

Two Photon Decays of $η_c$ from Lattice QCD

Ting Chen·Ying Chen·Ming Gong·Yu-Hong Lei·Ning Li·Chuan Liu·Yu-Bin Liu·Zhaofeng Liu·Jian-Ping Ma·Wei-Feng Qiu·Zhan-Lin Wang·Jian-Bo Zhang
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Abstract

We present an exploratory lattice study for the two-photon decay of $η_c$ 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 $Γ\simeq 1.122(14)$KeV which is smaller than the previous quenched result and most of the current experimental results. Possible reasons are discussed.

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Ting Chen, Ying Chen, Ming Gong, Yu-Hong Lei, Ning Li, Chuan Liu, Yu-Bin Liu, Zhaofeng Liu, Jian-Ping Ma, Wei-Feng Qiu, Zhan-Lin Wang, Jian-Bo Zhang. 2016-06-28. Two Photon Decays of $η_c$ from Lattice QCD. https://doi.org/10.1140/epjc%2Fs10052-016-4212-8

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