Integral moment of the Riemann zeta function and Hecke $L$-functions, II
Zhaoyan Chen
TL;DR
This work establishes an asymptotic formula for the mixed moment $\int_{-\infty}^{\infty} V(t/T)\, L(\tfrac{1}{2}+it,f)\, \zeta(\tfrac{1}{2}-it)^2\, dt$ on the critical line, for a Hecke cusp form $f$ (holomorphic or Maass). The author combines approximate functional equations, Voronoi summation, Mellin transforms, and stationary-phase analysis to isolate a main diagonal contribution $2cT\frac{L(1,f)^2}{\zeta(2)}$ (with $c=\int V$) and to bound the remaining terms by $O(T^{1/2+\varepsilon})$. The approach handles both the $t$-aspect and oscillatory test functions, enabling unweighted and smoothed formulations and yielding corollaries about related moments and mean-square bounds. The results extend prior mixed-moment studies by removing absolute values and providing uniform treatment across holomorphic and Maass cases, with implications for the understanding of moments of automorphic $L$-functions.Overall, the paper advances the analytic theory of mixed moments on the critical line by delivering a sharp asymptotic formula and robust error control using a synthesis of approximate functional equations, Voronoi theory, Mellin techniques, and stationary-phase analysis.
Abstract
In this paper, let $f$ be a Hecke cusp form for $SL(2,\mathbb{Z})$. We establish an asymptotic formula for the mixed moment of $ζ^{2}(s)$ and $L(s,f)$ on the critical line, valid for both holomorphic and Maass forms.
