Light Dark Matter Anomalies After LUX
  We examine the consistency of light dark matter (DM) elastic scattering in
CoGeNT, DAMA, and CDMS-Silicon in light of constraints from XENON, CDMS, LUX,
PICASSO and COUPP. We consider a variety of operators that have been employed
to reconcile anomalies with constraints, including anapole, magnetic dipole,
momentum-dependent, and isospin-violating DM. We find that elastic scattering
through these alternative operators does not substantially reduce the tension
between the signals and the null constraints for operators where at least two
of the three purported signals map onto a common space in the DM
mass--scattering cross-section plane. Taking a choice of the scintillation
efficiency that lies at the $-1 \sigma$ region of the Manzur et al measurement
relieves tension between signals and the LUX constraint---in particular for a
magnetic dipole interaction and a xenophobic interaction (though for the latter
the signal regions do not substantially overlap). We also find that modest
changes in the halo model does not alter this result. We conclude that, even
relaxing the assumption about the type of elastic scattering interaction and
taking a conservative choice for the scintillation efficiency, LUX and the
results from other null experiments remain in tension with a light DM elastic
scattering explanation of direct detection anomalies.
