2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/197535We present a novel source for supersymmetry breaking in orientifold models, and show that it gives a vanishing contribution to the vacuum energy at genus zero and three-half. We also argue that all the corresponding perturbative contributions to the vacuum energy from higher-genus Riemann surfaces vanish identically.13 pages, 1 figure. Final discussion and Refs addedHigh Energy Physics - Theorytext