Abstract: |
In supersymmetric (SUSY) models with the gravitino
being the lightest SUSY particle (LSP), the SUSY breaking scale
(i.e., the gravitino mass) could be determined by measuring the
lifetime of the next-to-lightest SUSY particle (NLSP). However, for
an ultralight gravitino of mass of O(1) eV, which is favored
cosmologically, the determination of the SUSY breaking scale, or the
gravitino mass, is difficult because the NLSP decay length is too
short to be measured directly. We propose a new determination of the
gravitino mass by measuring a branching fraction of two decay modes
of sleptons, and demonstrate that the gravitino mass may indeed be
determined at the LHC with an accuracy of a few 10% for an integrated
luminosity 10-100 fb-1. I will also mention dark matter candidates
for such a light gravitino LSP.
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