Bose-Einstein Condensate in solid helium*

Neutron scattering measurements at high momentum and energy transfers, often referred to as deep inelastic neutron scattering (DINS), is the most effective tool to explore the dynamics of single particles in condensed matter. In liquid and solid helium for example, these measurements reveal the Bose-Einstein condensate (BEC) fraction and the average single-particle kinetic energy. In this talk, I will present recent DINS measurements of BEC in solid $^4$He at temperatures below the reported \lq supersolid' transition temperature of 200 mK. Within our current instrumental precision, we find that the BEC fraction, $n_0$, is consistent with zero.