We analyze the possibilities of pairing between two different fermion speci
es in asymmetric matter at low density. While the direct interaction allows
pairing only for very small asymmetries, the pairing mediated by polarizat
ion effects is always possible, with a pronounced maximum at finite asymmet
ry. We present analytical results up to second order in the low-density par
ameter k(F)a. (C) 2001 Elsevier Science B.V. All rights reserved.