Review of speculative “disaster scenarios” at RHIC

This paper discusses speculative disaster scenarios inspired by hypothetical new fundamental processes that might occur in high-energy relativistic heavy-ion collisions. The authors estimate the parameters relevant to black-hole production and find that they are absurdly small. They show that other accelerator and (especially) cosmic-ray environments have already provided far more auspicious opportunities for transition to a new vacuum state, so that existing observations provide stringent bounds. The possibility of producing a dangerous strangelet is discussed in most detail. The authors argue that four separate requirements are necessary for this to occur: existence of large stable strangelets, metastability of intermediate size strangelets, negative charge for strangelets along the stability line, and production of intermediate size strangelets in the heavy ion environment. Both theoretical and experimental reasons why each of these appears unlikely are discussed. In particular, the authors know of no plausible suggestion for why the third or especially the fourth might be true. Given minimal physical assumptions, the continued existence of the Moon, in the form we know it, despite billions of years of cosmic-ray exposure, provides powerful empirical evidence against the possibility of dangerous strangelet production.