First measurement of Λ› N inelastic scattering with Λ from e + e - → J/Ψ →†’ ΛΛ›(over bar)

Using an e + e - collision data sample of (10087 ± 44)x10 6 J/Ψ. events taken at the center-of-mass energy of 3.097 GeV by the BESIII detector at the BEPCII collider, the process Λ + N → Σ + + X is studied for the first time employing a novel method. The Σ + hyperons are produced by the collisions of Λ hyperons from J/Ψ decays with nuclei in the material of the BESIII detector. The total cross section of Λ + 9 Be → Σ + + X is measured to be σ = (37.3 ± 4.7 ± 3.5) mb with Λ momenta within [1.057, 1.091] GeV/c, where the uncertainties are statistical and systematic, respectively. This analysis is the first study of Λ-nucleon interactions at an e + e - collider, providing information and constraints relevant for the strong-interaction potential, the origin of color confinement, the unified model for baryon-baryon interactions, and the internal structure of neutron stars.