2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/180271Within a scalar model theory of gravity, where the interaction between particles is given by the half-retarded + half-advanced solution of the scalar wave equation, we consider an N-body problem: we investigate configurations of N particles which form an equilateral N-angle and are in helical motion about their common center. We prove that there exists a unique equilibrium configuration and compute the equilibrium radius explicitly in a post-Newtonian expansion.5 pages, 1 figure; minor corrections and changes; accepted for publication in Physical Review LettersGeneral Relativity and Quantum Cosmologytext