Speaker
Description
The study of multi-baryon interactions, particularly those involving strange quarks, is key to understanding dense nuclear matter and the equation of state of neutron stars. While two-body nucleon-nucleon ($N$-$N$) and hyperon-nucleon ($Y$-$N$) forces are relatively well constrained, genuine three-body interactions remain largely unexplored. By comparing systems composed solely of nucleons with those containing both nucleons and hyperons, one can investigate how strangeness influences baryonic dynamics.
Femtoscopy offers a unique tool to access these few-body dynamics at distances of a few femtometers. By measuring momentum correlations among particles emitted close in space and time, femtoscopy directly probes final-state interactions and quantum statistical effects. At STAR, this technique can be applied to Au+Au collisions at $\sqrt{s_{NN}}$ = 3 GeV, where high baryon density and near-threshold particle production enable unprecedented studies of multi-baryon correlations.
In this talk, we will present the first measurements of three-baryon correlation functions for p–p–p and p–p–$\Lambda$ systems at $\sqrt{s_{NN}}$ = 3 GeV in the STAR experiment. The p–p–p correlations serve as a baseline for $N$-$N$-$N$ dynamics, while the inclusion of $\Lambda$ hyperons in the p–p–$\Lambda$ systems allows us to explore how strangeness modifies three-body forces through $Y$-$N$-$N$ couplings in addition to Coulomb interactions. Comparisons with theoretical calculations and transport models highlight the sensitivity of these measurements to genuine three-body forces in dense baryonic matter.
