Measuring K$^0_{\rm S}$K$^{\rm{\pm}}$ interactions using pp collisions at $\sqrt{s}=7$ TeV

TL;DR

This paper reports the first femtoscopic correlation measurements between K$^0_{S}$ and K$^{ m \pm}$ particles in proton-proton collisions at 7 TeV, providing insights into the nature of the $a_0(980)$ resonance.

Contribution

It introduces the first measurement of K$^0_{S}$K$^{ m \pm}$ correlations in pp collisions at 7 TeV, supporting the tetraquark interpretation of the $a_0(980)$ resonance.

Findings

Correlations consistent with final-state interactions via $a_0(980)$

Kaon source radius and correlation strength are similar for K$^0_{S}$K$^{ m -}$ and K$^0_{S}$K$^{ m +}$

Results support the tetraquark structure of $a_0(980)$

Abstract

We present the first measurements of femtoscopic correlations between the K$^0_{\rm S}$ and K$^{\rm \pm}$ 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 $a_0(980)$ 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$^{\rm +}$. 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$^0_{\rm S}$K$^{\rm \pm}$ measurement in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV. Combined with the Pb-Pb results, our pp analysis is found to be compatible with the interpretation of the $a_0(980)$ having a tetraquark structure instead of that of a diquark.