The interactions of kaons (K) and antikaons ($\mathrm{\overline{K}}$) with few nucleons (N) were studied so far using kaonic atom data and measurements of kaon production and interaction yields in nuclei. Some details of the three-body KNN and $\mathrm{\overline{K}}$NN dynamics are still not well understood, mainly due to the overlap with multi-nucleon interactions in nuclei. An alternative method to probe the dynamics of three-body systems with kaons is to study the final state interaction within triplet of particles emitted in pp collisions at the Large Hadron Collider, which are free from effects due to the presence of bound nucleons. This Letter reports the first femtoscopic study of p$-$p$-$K$^+$ and p$-$p$-$K$^-$ correlations measured in high-multiplicity pp collisions at $\sqrt{s}$ = 13 TeV by the ALICE Collaboration. The analysis shows that the measured p$-$p$-$K$^+$ and p$-$p$-$K$^-$ correlation functions can be interpreted in terms of pairwise interactions in the triplets, indicating that the dynamics of such systems is dominated by the two-body interactions without significant contributions from three-body effects or bound states.
Eur. Phys. J. A (2023) 59:298
HEP Data
e-Print: arXiv:2303.13448 | PDF | inSPIRE
CERN-EP-2023-051
Figure group
Figure 1
Correlation functions for (p$-$p)$-$K$^+$ (panel $\mathrm{a_1}$), (p$-$p)$-$K$^-$ (panel $\mathrm{a_2}$), p$-$(p$-$K$^+$) (panel $\mathrm{b_1}$), p$-$(p$-$K$^-$) (panel $\mathrm{b_2}$) as well as the total lower-order contributions for p$-$p$-$K$^+$ (panel $\mathrm{c_1}$) and p$-$p$-$K$^-$ (panel $\mathrm{c_2}$) as a function of $Q_3$. The points represent the results obtained using the data-driven approach, with the statistical and systematic uncertainties represented by the error bars and the green boxes, respectively. The grey bands are the expectations of the projector method, with the band width representing the combined statistical and systematic uncertainties. |   |
Figure 2
Correlation functions (data points) for p$-$p$-$K$^+$ (top panel) and p$-$p$-$K$^-$ (bottom panel) compared to the lower-order contributions evaluated using the projector method (grey bands). Statistical and systematic uncertainties are represented by error bars and green boxes, respectively. The band widths represent the combined statistical and systematic uncertainties propagated from the two-particle correlation functions used as input to the projector method. |   |
Figure 3
Cumulants for the p$-$p$-$K$^+$ (top panel) and p$-$p$-$K$^-$ (bottom panel) primary triplets. The error bars and the blue boxes on the data points represent the statistical and systematic uncertainties, respectively. The $n_\sigma$ deviations from zero in each bin are shown in the bottom panels, adding in quadrature the statistical and systematic uncertainties of the data. |   |