\documentclass[12pt]{article}
\usepackage{amssymb,amsmath,amscd,concmath,amsfonts}
\pagestyle{empty}
\begin{document}
\begin{equation*}e^{\widehat{\xi}_1\theta_1} e^{\widehat{\xi}_2\theta_2} p = q\end{equation*}
\end{document}