LOOP CORRECTIONS TO THE UNIVERSAL HYPERMULTIPLET

The universal hypermultiplet arises as a subsector of every Calabi-Yau compactification of M-theory of type II string theory. Classically it s moduli space is the quaternionic space SU(2,1)/U(2). we show that th is moduli space receives a one-loop correction proportional to the Eul er character of the Calabi-Yau, which can locally be absorbed by a cer tain constant shift of the fields. The correction vanishes in the limi t that the Planck mass is taken to infinity, and hence is essentially gravitational in nature. (C) 1998 Published by Elsevier Science B.V.