UC Irvine

In supergravity theories, a natural possibility is that neutralinos or sleptons freeze out at their thermal relic density, but then decay to gravitinos after about a year. The resulting gravitinos are then superWIMPs -- superweakly-interacting massive particles that naturally inherit the desired relic density from late decays of conventional WIMPs. SuperWIMP dark matter escapes all conventional searches. However, the late decays that produce superWIMPs provide new and promising early universe signatures for cold dark matter.