Lattice calculation of χc0 → 2γ decay width

We perform a lattice QCD calculation of the chi(c0) -> 2 gamma decay width using a model-independent method that does not require the momentum extrapolation of corresponding off-shell form factors. The simulation is performed on ensembles of N-f = 2 twisted mass lattice QCD gauge configurations with three different lattice spacings. After the continuum extrapolation, the decay width is obtained to be Gamma(gamma gamma)(chi(c0)) = 3.65(83)(stat)(21)(lat.syst)(66)(syst)keV. Regardless of this large statistical error, our result is compatible with the experimental results within 1.3 sigma. Potential improvements of the lattice calculation in the future are also discussed.

Automated summary

In this study, a lattice QCD calculation of the chi(c0) -> 2 gamma decay width is performed using a model-independent method. The result is obtained after a continuum extrapolation, with a compatibility to experimental results within 1.3 sigma. Potential improvements for lattice calculations in the future are also discussed.