Measuring Interactions Using pp Collisions at TeV

We present the first measurements of femtoscopic correlations between the ${K}_{S}^{0}$ and ${K}^{±}$ particles in pp collisions at $\sqrt{s}=7$ TeV measured by the ALICE experiment. The observed femtoscopic correlations are consistent with final-state interactions proceeding solely via the ${a}_{0}\left(980\right)$ resonance. The extracted kaon source radius and correlation strength parameters for ${K}_{S}^{0}{K}^{-}$ are found to be equal within the experimental uncertainties to those for ${K}_{S}^{0}{K}^{+}$. Results of the present study are compared with those from identical-kaon femtoscopic studies also performed with pp collisions at $\sqrt{s}=7$ TeV by ALICE and with a ${K}_{S}^{0}{K}^{±}$ measurement in Pb–Pb collisions at $\sqrt{{s}_{\mathrm{NN}}}=2.76$ TeV. Combined with the Pb–Pb results, our pp analysis is found to be compatible with the interpretation of the ${a}_{0}\left(980\right)$ having a tetraquark structure instead of that of a diquark.