Cohomological splitting over rationally connected bases

We prove a cohomological splitting result for Hamiltonian fibrations over enumeratively rationally connected symplectic manifolds. As a key application, we prove that the cohomology of a smooth, projective family over a smooth stably rational projective variety splits additively over any field. The main ingredient in our arguments is the theory of Fukaya-Parker-Ono (FOP) perturbations developed by the first and third author, which allows one to define integer-valued Gromov-Witten type invariants.