Figure 2

K$^\pm$K$^\pm$ experimental correlation functions corrected for purity according to Eq. (\ref{eq:PurCorr}) (red points) and EPOS 3 model baselines (black points) versus pair relative invariant momentum $q_\mathrm{inv}$. The CFs are presented in three event multiplicity classes: 0--20\%, 20--40\% and 40--90\% and two pair transverse momentum $k_{\mathrm T}$ bins: (0.2--0.5) and (0.5--1.0) GeV/$c$. The black line shows the fit of EPOS 3 by a first-order polynomial for $0< q_\mathrm{inv}< 1.0$ GeV/$c$. The red line shows the subsequent fit of the CF up to $q_\mathrm{inv}< $0.5 GeV/$c$ by Eq. (\ref{eq:BS_CF}). The CFs are normalized to unity in the range $0.5< q_\mathrm{inv}< 1.0$ GeV/$c$. Statistical (lines) and systematic uncertainties (boxes) are shown.