We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the $U(1)$ global symmetry associated with the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vacuum expectation value of the waterfall field, which is well constrained by diverse cosmological observations.

• Received 14 September 2006

DOI:https://doi.org/10.1103/PhysRevLett.98.161302