Primordial black hole formation in a double-inflation model in supergravity

It has been recently pointed out that the initial value problem in new inflation models is naturally solved by supergravity effects if there exists a preinflation before the new inflation. We study this double inflation model in detail and find that density fluctuations on small cosmological scales are much larger than those on large scales due to the peculiar property of the new inflation. We show that this results in the production of primordial black holes which have similar to 1M. masses in a certain parameter region of the double inflation model. We stress that these black holes may be identified with massive compact halo objects observed in the halo of our galaxy.