Finite-temperature momentum distribution of a trapped Fermi gas

We present measurements of the temperature-dependent momentum distribution of a trapped Fermi gas consisting of {sup 40}K in the BCS to Bose-Einstein condensation crossover regime. Accompanying theoretical results based upon a simple mean-field ground state are compared to the experimental data. Nonmonotonic effects associated with temperature T arise from the competition between thermal broadening and a narrowing of the distribution induced by the decrease in the excitation gap {delta}(T) with increasing T.