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arXiv · 2207.13623

The two-photon decay of X(6900) from light-by-light scattering at the LHC

Volodymyr Biloshytskyi·Vladimir Pascalutsa·Lucian Harland-Lang·Bogdan Malaescu·Kristof Schmieden·Matthias Schott
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Abstract

The LHCb Collaboration has recently discovered a structure around 6.9 GeV in the double-$J/\psi$ mass distribution, possibly a first fully-charmed tetraquark state $X(6900)$. Based on vector-meson dominance (VMD) such a state should have a significant branching ratio for decaying into two photons. We show that the recorded LHC data for the light-by-light scattering may indeed accommodate for such a state, with a $\gamma \gamma$ branching ratio of order of $10^{-4}$, which is larger even than the value inferred by the VMD. The spin-parity assignment $0^{-+}$ is in better agreement with the VMD prediction than $0^{++}$, albeit not significantly at the current precision. Further light-by-light scattering data in this region, clarifying the nature of this state, should be obtained in the Run 3 and probably in the high-luminosity phase of the LHC (Run 4 etc.).

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Volodymyr Biloshytskyi, Vladimir Pascalutsa, Lucian Harland-Lang, Bogdan Malaescu, Kristof Schmieden, Matthias Schott. 2022-07-27. The two-photon decay of X(6900) from light-by-light scattering at the LHC. https://doi.org/10.1103/physrevd.106.l111902

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