Abstract
This Letter presents the first experimental evidence of the attractive strong interaction between a proton and a meson. The result is obtained from two-particle correlations of combined pairs measured in high-multiplicity collisions at by the ALICE Collaboration. The spin-averaged scattering length and effective range of the interaction are extracted from the fully corrected correlation function employing the Lednický-Lyuboshits approach. In particular, the imaginary part of the scattering length vanishes within uncertainties, indicating that inelastic processes do not play a prominent role for the interaction. These data demonstrate that the interaction is dominated by elastic scattering. Furthermore, an analysis employing phenomenological Gaussian- and Yukawa-type potentials is conducted. Under the assumption of the latter, the coupling constant is found to be . This work provides valuable experimental input to accomplish a self-consistent description of the interaction, which is particularly relevant for the more fundamental studies on partial restoration of chiral symmetry in nuclear medium.
- Received 16 June 2021
- Revised 8 September 2021
- Accepted 14 September 2021
DOI:https://doi.org/10.1103/PhysRevLett.127.172301
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
© 2021 CERN, for the ALICE Collaboration