# How to write the following equation in LaTeX?

I need this output with the same harpoon right arrow:

\documentclass[titlepage]{article}
\usepackage[cm]{fullpage}
\usepackage{amsmath,amssymb}
\usepackage{accents}
\newcommand{\vect}[1]{\accentset{\rightharpoonup}{#1}}
\begin{document}
$\vect{L^2((0,T);W^{1,2}(\Omega)')}$
\end{document}


\documentclass{article}
\newcommand{\vect}[1]{\accentset{\xrightharpoonup{\hphantom{\scalebox{.4}{$#1$}}}}{#1}}
$\vect{L^2((0,T);W^{1,2}(\Omega)')}$

The content is scaled to 40% of its width (change .4 to suit your needs) and only uses the horizontal width in a \phantom. The extensible harpoon is provided as part of mathtools (which loads amsmath by default).