Supersymmetric models often predict a lightest superpartner (LSP) which is electrically charged and stable on the time scales of collider experiments. If such a particle were to be observed experimentally, is it possible to determine whether or not it is stable on cosmological time scales? Charged, stable particles are usually considered to be excluded by cosmological arguments coupled with terrestrial searches for anomalously heavy water molecules. But when the cosmology is significantly altered, as can happen in models with large extra dimensions, these arguments are in turn significantly weakened. In this paper we suggest an alternate way to use searches for superheavy water to constrain the lifetimes of long-lived, charged particles, independent of most cosmological assumptions. By considering supersymmetric production by cosmic rays in the upper atmosphere, we are able to use current bounds on superheavy water to constrain the mass scale of squarks and gluinos to be greater than about $230\mathrm{GeV},$ assuming a stable, charged LSP. This bound can be increased, but only by significantly increasing the size of the initial water sample tested.

• Received 12 August 2002

DOI:https://doi.org/10.1103/PhysRevD.66.075007