Second moments of Rankin-Selberg convolution and shifted Dirichlet series

Abstract

In this paper we work over ${\Gamma }_0(N)$, for any $N$ and write the spectral moment of a product of two distinct Rankin-Selberg convolutions at a general point on the critical line $\frac{1}{2}+it$ as a main term plus a sharp error term in the $t$ aspect and the spectral aspect. As a result we obtain hybrid Weyl type subconvexity results in the $t$ and spectral aspects. Also, for fixed modular forms $f$, $g$ of even weight $k\ge 4$ we show there exists a Maass cusp form $u_j$ such that $L(1/2,f\times u_j)$, $L(1/2,g\times u_j)$ are simultaneous non-zero.

42 pages