Studying the $a_0$(980) tetraquark candidate using $K^0_s K^{\pm}$ interactions in the LHC ALICE collaboration

The a0(980) meson has been considered a tetraquark candidate for over 40 years, but its actual quark content remains in question. The ALICE Collaboration has carried out measurements of K0 SK ± interactions with pp collisions at √ s = 7 TeV and Pb-Pb collisions at √ sNN = 2.76 TeV to study the a0(980) using the method of two-particle femtoscopy. The a0(980) provides the final-state interaction between the kaons in the pair that is used in the femtoscopic analysis of these collisions. The measured femtoscopic source parameters are compared with source parameters extracted in identical-kaon measurements obtained in the same colliding systems. Using a simple geometric argument, our results are found to be compatible with the interpretation of the a0(980) having a tetraquark structure instead of that of a diquark.