Investigation of K$^{+}$K$^{-}$ interactions via femtoscopy in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}} =2.76$ TeV at the LHC

TL;DR

This study uses femtoscopy to analyze K+K- correlations in Pb-Pb collisions at 2.76 TeV, extracting resonance properties and examining meson production mechanisms.

Contribution

It provides new measurements of the f0(980) resonance parameters and insights into the origin of phi(1020) mesons in heavy-ion collisions.

Findings

Measured f0(980) mass and width are consistent with previous results.

The phi(1020) peak height decreases with increasing source size.

Phi(1020) yield is mainly from direct hadronization, with a minor final-state interaction contribution.

Abstract

Femtoscopic correlations of non-identical charged kaons ($\rm K^+ K^-$) are studied in Pb$-$Pb collisions at a center-of-mass energy per nucleon$-$nucleon collision $\sqrt{s_{\mathrm{NN}}} =2.76$ TeV by ALICE at the LHC. One-dimensional $\rm K^+ K^-$ correlation functions are analyzed in three centrality classes and eight intervals of particle-pair transverse momentum. The Lednick\'y and Luboshitz interaction model used in the $\rm K^+ K^-$ analysis includes the final-state Coulomb interactions between kaons and the final-state interaction through $a_{0}$(980) and $f_{0}$(980) resonances. The mass of $f_{0}$(980) and coupling were extracted from the fit to $\rm K^+ K^-$ correlation functions using the femtoscopic technique. The measured mass and width of the $f_{0}$(980) resonance are consistent with other published measurements. The height of the $\phi$(1020) meson peak present in the $\rm K^+ K^-$ correlation function rapidly decreases with increasing source radius, qualitatively in agreement with an inverse volume dependence. A phenomenological fit to this trend suggests that the $\phi$(1020) meson yield is dominated by particles produced directly from the hadronization of the system. The small fraction subsequently produced by final-state interactions could not be precisely quantified with data presented in this paper and will be assessed in future work.