  A light supersymmetric top quark partner (stop) with a mass nearly degenerate
with that of the Standard Model (SM) top quark can evade direct searches. The
precise measurement of SM top properties such as the cross-section has been
suggested to give a handle for this `stealth stop' scenario. We present an
estimate of the potential impact a light stop may have on top quark mass
measurements. The results indicate that certain light stop models may induce a
bias of up to a few GeV, and that this effect can hide the shift in, and hence
sensitivity from, cross-section measurements. The studies make some simplifying
assumptions for the top quark measurement technique, and are based on
truth-level samples.
