2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/200644It is widely thought that this question has a positive answer, but we argue that the support for this belief from both experiment and theory is weak or nonexistent. We then list some of the ramifications of a negative answer.8 pages, no figures, version to appear in NJPHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext