Measuring K\(^0_{\rm S}\)K\(^{\rm \pm}\) interactions using Pb-Pb collisions at \({\sqrt{s_{\rm NN}}=2.76}\) TeV

Abstract

We present the first ever measurements of femtoscopic correlations between the K\(^0_{\rm S}\) and K\(^{\rm \pm}\) particles. The analysis was performed on the data from Pb-Pb collisions at \(\sqrt{s_{\rm NN}}=2.76\) TeV measured by the ALICE experiment. The observed femtoscopic correlations are consistent with final-state interactions proceeding via the \(a_0(980)\) resonance. The extracted kaon source radius and correlation strength parameters for K\(^0_{\rm S}\)K\(^{\rm -}\) are found to be equal within the experimental uncertainties to those for K\(^0_{\rm S}\)K\(^{\rm +}\), Comparing the results of the present study with those from published identical-kaon femtoscopic studies by ALICE, mass and coupling parameters for the \(a_0\) resonance are constrained. Our results are also compatible with the interpretation of the \(a_0\) having a tetraquark structure over that of a diquark.