We define Symplectic cohomology groups for a class of symplectic fibrations with closed symplectic base and convex at infinity fiber. The crucial geometric assumption on the fibration is a negativity property reminiscent of negative curvature in complex vector bundles. When the base is symplectically aspherical we construct a spectral sequence of Leray-Serre type converging to the Symplectic cohomology groups of the total space, and we use it to prove new cases of the Weinstein conjecture.
Comment: 70 pages, 1 figure. Major revision. The paper has been entirely reorganized for clarity. Sections 4 to 7, including the proofs of the main theorems, have undergone extensive rewriting. Several incorrect claims have been corrected. Rescaling of the period of the orbits in the Floer complex is no more needed. Appendix B has been replaced with Lemma 5.5.