Charged kaon femtoscopic correlations in p$-$Pb collisions at $\mathbf{\sqrt{{\textit s}_{\rm NN}}}=5.02$ TeV with ALICE at the LHC

Abstract: Particle correlations at small relative momenta can be used to measure the space$-$time characteristics of particle production on the femtoscopic (fm=10$^{-15}$ m) level in high-energy collisions. Such correlations arise due to quantum statistics and final state interactions. We report correlations of two charged identical kaons measured in p$-$Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV by the ALICE experiment at the LHC. The femtoscopic invariant radii and correlation strengths are extracted from the one-dimensional kaon correlation functions and are compared to those obtained in pp and Pb$-$Pb collisions at $\sqrt{s}=7$ TeV and $\sqrt{s_{\rm NN}}=2.76$ TeV, respectively. Kaon femtoscopy in p$-$Pb collisions is an important supplement to that in pp and Pb$-$Pb collisions because it allows one to understand the particle production mechanisms in different collision systems. It also complements the existing pion correlation results. The obtained radii increase with increasing multiplicity and decrease with increasing pair transverse momentum. At comparable multiplicity, the radii measured in p$-$Pb collisions are close to those observed in pp collisions, whereas it is difficult to compare them with the results from Pb$-$Pb collisions because of a big multiplicity gap.