Measuring K0S K± interactions using pp collisions at √s = 7 TeV

We present the first measurements of femtoscopic correlations between the K0 and K± particles in pp √S collisions at s = 7 TeV measured by the ALICE experiment. The observed femtoscopic correlations are consistent with final-state interactions proceeding solely via the a0(980) resonance. The extracted kaon source radius and correlation strength parameters for K0SK− are found to be equal within the experimental uncertainties to those for K0K+. Results of the present study are compared with those S√ from identical-kaon femtoscopic studies also performed with pp collisions at s = 7 TeV by ALICE and with a K0S K± measurement in Pb–Pb collisions at √sNN = 2.76 TeV. Combined with the Pb–Pb results, our pp analysis is found to be compatible with the interpretation of the a0(980) having a tetraquark structure instead of that of a diquark.