Femtoscopic correlation functions between the lightest charmed hadrons

Abstract

Femtoscopic momentum correlations probe low-energy interactions of short-lived charmed hadrons that are inaccessible to conventional scattering experiments. We calculate the correlation functions of $D^{+}D^{+}$, $D^{0}D^{0}$, $D^{+}D^{0}$, and $Λ_c^+Λ_c^+$ in Pb--Pb collisions at $\sqrt{s_{\rm NN}}=5.02$~TeV, using species-dependent non-Gaussian PHSD sources constructed from hadronization points and strong interactions calibrated to lattice-QCD scattering lengths: OBE and EFT-contact models for $DD$, and an EFT-contact model for $Λ_cΛ_c$. Coulomb and quantum-statistical effects are included consistently. Although the calibrated interactions are weakly repulsive, the channels separate the relevant effects: $D^{+}D^{0}$, free of Coulomb distortion and identical-particle interference, gives the cleanest access to the $DD$ strong interaction, whereas $Λ_c^+Λ_c^+$ is most pronounced in peripheral collisions, where the compact source enhances the low-momentum signal. The $Λ_cΛ_c$ input is taken from lattice QCD at a nonphysical pion mass, so its physical-point shift is not quantified here. Within these stated inputs, the results provide ALICE-ready benchmark correlations and background references; the quoted bands propagate only the lattice scattering-length uncertainty.