We have observed exclusive production of the exotic $X(3872)$ hadron in the
reaction $mu^+~N
ightarrow mu^+ (J!/!psipi^+pi^-)pi^{pm}~N’$ using
COMPASS data collected with incoming muons of 160~GeV/$c$ and 200~GeV/$c$
momentum. The statistical significance of the $X(3872)$ signal is 6$sigma$.
The shape of the two-pion mass distribution shows disagreement with previous
observations. The product of cross section and branching fraction of the
$X(3872)$ decay into $J!/!psipipi$ is determined to be
71$pm$28(stat)$pm$39(syst)~pb.
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