A referee found an error in the proof of the Theorem 2 that we could not fix.
More precisely, the proof of Lemma 2.1 is incorrect. Hence the fact that
integer cohomology of complement of toric Weyl arrangements is torsion free is
still a conjecture.
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A toric arrangement is a finite set of hypersurfaces in a complex torus,
every hypersurface being the kernel of a character. In the present paper we
prove that if \Cal T_{\wdt W} is the toric arrangement defined by the
\textit{cocharacters} lattice of a Weyl group \wdt W, then the integer
cohomology of its complement is torsion free