Constraining the K ¯ N coupled channel dynamics using femtoscopic correlations at the LHC

The interaction of K−with protons is characterised by the presence of several coupled channels, systems like K 0 n and π with a similar mass and the same quantum numbers as the K−p state. The strengths of these couplings to the K−p system are of crucial importance for the understanding of the nature of the (1405) resonance and of the attractive K−p strong interaction. In this arti- cle, we present measurements of the K−p correlation func- tions in relative momentum space obtained in pp collisions at √s = 13 TeV, in p–Pb collisions at √sNN = 5.02 TeV, and (semi)peripheral Pb–Pb collisions at √sNN = 5.02 TeV. The emitting source size, composed of a core radius anchored to the K+p correlation and of a resonance halo specific to each particle pair, varies between 1 and 2 fm in these collision sys- tems. The strength and the effects of the K 0 n and π inelas- tic channels on the measured K−p correlation function are investigated in the different colliding systems by comparing the data with state-of-the-art models of chiral potentials. A novel approach to determine the conversion weights ω, nec- essary to quantify the amount of produced inelastic channels in the correlation function, is presented. In this method, parti- cle yields are estimated from thermal model predictions, and their kinematic distribution from blast-wave fits to measured data. The comparison of chiral potentials to the measured K−p interaction indicates that, while the π –K−p dynam- ics is well reproduced by the model, the coupling to the K 0 n channel in the model is currently underestimated