Moment zeta functions provide a diophantine formulation for the distribution of rational points on a family of algebraic varieties over finite fields. They also form algebraic approximations to Dwork's p-adic unit root zeta functions. In this paper, we use l-adic cohomology to calculate all the higher moment zeta functions for the mirror family of the Calabi-Yau family of smooth projective hypersurfaces over finite fields. Our main result is a complete determination of the purity decomposition and the trivial factors for the moment zeta functions.

For the Artin-Schreier curve y - y = f(x) defined over a finite field F of q elements, the celebrated Weil bound for the number of F -rational points can be sharp, especially in super-singular cases and when r is divisible. In this paper, we show how the Weil bound can be significantly improved, using ideas from moment L-functions and Katz's work on ℓ-adic monodromy calculations. Roughly speaking, we show that in favorable cases (which happens quite often), one can remove an extra √q factor in the error term. © 2010 The Author(s). q q qr