Identifying Contributions to the Stellar Halo from Accreted, Kicked-Out,
  and In Situ Populations
  [Abridged] We present a medium-resolution spectroscopic survey of late-type
giant stars at mid-Galactic latitudes of (30$^{\circ}<|b|<60^{\circ}$),
designed to probe the properties of this population to distances of $\sim$9
kpc. Because M giants are generally metal-rich and we have limited
contamination from thin disk stars by the latitude selection, most of the stars
in the survey are expected to be members of the thick disk
($<$[Fe/H]$>\sim$-0.6) with some contribution from the metal-rich component of
the nearby halo.
  Here we report first results for 1799 stars. The distribution of radial
velocity (RV) as a function of l for these stars shows (1) the expected thick
disk population and (2) local metal-rich halo stars moving at high speeds
relative to the disk, that in some cases form distinct sequences in RV-$l$
space. High-resolution echelle spectra taken for 34 of these "RV outliers"
reveal the following patterns across the [Ti/Fe]-[Fe/H] plane: seventeen of the
stars have abundances reminiscent of the populations present in dwarf
satellites of the Milky Way; eight have abundances coincident with those of the
Galactic disk and more metal-rich halo; and nine of the stars fall on the locus
defined by the majority of stars in the halo. The chemical abundance trends of
the RV outliers suggest that this sample consists predominantly of stars
accreted from infalling dwarf galaxies. A smaller fraction of stars in the RV
outlier sample may have been formed in the inner Galaxy and subsequently kicked
to higher eccentricity orbits, but the sample is not large enough to
distinguish conclusively between this interpretation and the alternative that
these stars represent the tail of the velocity distribution of the thick disk.
Our data do not rule out the possibility that a minority of the sample could
have formed from gas {\it in situ} on their current orbits.
