Experimental Evidence for an Attractive p-$\phi$ Interaction

The collaboration
Phys.Rev.Lett. 127 (2021) 172301, 2021.

Abstract (data abstract)
This represents the first experimental evidence of the attractive strong interaction between a proton and a $\phi$ meson. The result is obtained from two-particle correlations of combined $\mathrm{p}-\phi\oplus\mathrm{\overline{p}}-\phi$ pairs measured in high-multiplicity pp collisions at $\sqrt{s} = 13$ TeV by the ALICE collaboration. The spin-averaged scattering length and effective range of the $\mathrm{p}-\phi$ interaction are extracted from the fully corrected correlation function employing the Lednick'y-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 $\mathrm{p}-\phi$ interaction. These data demonstrate that the interaction is dominated by elastic $\mathrm{p}-\phi$ scattering. Furthermore, an analysis employing phenomenological Gaussian- and Yukawa-type potentials is conducted. This work provides valuable experimental input to accomplish a self-consistent description of the N-$\phi$ interaction, which is particularly relevant for the more fundamental studies on partial restoration of chiral symmetry in nuclear medium.