First study of the two-body scattering involving charm hadrons

Abstract

This Letter presents the first measurement of the interaction between charm hadrons and nucleons. The two-particle momentum correlations of \(\mathrm{pD^-}\) and \(\mathrm{\overline{p}D}^+\) pairs are measured by the ALICE Collaboration in high-multiplicity pp collisions at \(\sqrt{s} = 13~\mathrm{TeV}\). The data are compatible with the Coulomb-only interaction hypothesis within (1.1-1.5)\(\sigma\). Considering an attractive nucleon(N)\(\overline{\mathrm{D}}\) strong interaction, in contrast to most model predictions which suggest an overall repulsive interaction, slightly improves the level of agreement. This measurement allows for the first time an estimation of the 68% confidence level interval for the isospin \(\mathrm{I}=0\) inverse scattering length of the \(\mathrm{N\overline{D}}\) state \({f_{0,~\mathrm{I}=0}^{-1} \in [-0.4,0.9]~\mathrm{fm^{-1}}}\), assuming negligible interaction for the isospin \(\mathrm{I}=1\) channel.