The cosmological implication of a double inflation model with hybrid $+$ new inflations in supergravity is studied. The hybrid inflation drives an inflaton for new inflation close to the origin through supergravity effects and new inflation naturally occurs. If the total e-fold number of new inflation is smaller than $\sim 60,$ both inflations produce cosmologically relevant density fluctuations. Both cluster abundances and galaxy distributions provide strong constraints on the parameters in the double inflation model assuming the ${\Omega }_0=1\mathrm{}$ standard cold dark matter scenario. The future satellite experiments to measure the angular power spectrum of the cosmic microwave background will make a precise determination of the model parameters possible.

• Received 13 August 1999

DOI:https://doi.org/10.1103/PhysRevD.61.023517