Two-photon decay of fully-charmed tetraquarks from light-by-light scattering at the LHC

Abstract

The LHC newly-discovered resonant structures around 7 GeV, such as the X(6900), could be responsible for the observed excess in light-by-light scattering between 5 and 10 GeV. We show that the ATLAS data for light-bylight scattering may indeed be explained by such a state with the γγ branching ratio of order of 10−4. This is much larger than the value inferred by the vectormeson dominance, but agrees quite well with the tetraquark expectation for the nature of this state. Further light-by-light scattering data in this region, obtained during the ongoing Run-3 and future Run-4 of the LHC, are required to pin down these states in γγ channel.