  There exists a need to address and resolve the growing evidence for
short-baseline neutrino oscillations and the possible existence of sterile
neutrinos. Such non-standard particles require a mass of $\sim 1$ eV/c$^2$, far
above the mass scale associated with active neutrinos, and were first invoked
to explain the LSND $\bar \nu_\mu \rightarrow \bar \nu_e$ appearance signal.
More recently, the MiniBooNE experiment has reported a $2.8 \sigma$ excess of
events in antineutrino mode consistent with neutrino oscillations and with the
LSND antineutrino appearance signal. MiniBooNE also observed a $3.4 \sigma$
excess of events in their neutrino mode data. Lower than expected
neutrino-induced event rates using calibrated radioactive sources and nuclear
reactors can also be explained by the existence of sterile neutrinos. Fits to
the world's neutrino and antineutrino data are consistent with sterile
neutrinos at this $\sim 1$ eV/c$^2$ mass scale, although there is some tension
between measurements from disappearance and appearance experiments. In addition
to resolving this potential major extension of the Standard Model, the
existence of sterile neutrinos will impact design and planning for all future
neutrino experiments. It should be an extremely high priority to conclusively
establish if such unexpected light sterile neutrinos exist. The Spallation
Neutron Source (SNS) at Oak Ridge National Laboratory, built to usher in a new
era in neutron research, provides a unique opportunity for US science to
perform a definitive world-class search for sterile neutrinos.
