  We have experimentally studied the magnetic-field dependence of the decay of
a Bose-Einstein condensate of metastable 4He atoms confined in an optical
dipole trap, for atoms in the m=+1 and m=-1 magnetic substates, and up to 450
G. Our measurements confirm long-standing calculations of the two-body loss
rate coefficient that show an increase above 50 G. We demonstrate that for m=-1
atoms, decay is due to three-body recombination only, with a three-body loss
rate coefficient of 6.5(0.4)(0.6)10^(-27)cm^6s^(-1), which is interesting in
the context of universal few-body theory. We have also searched for a
recently-predicted d-wave Feshbach resonance, but did not observe it.
