Upper Limit on the Photoproduction Cross Section of the Spin-Exotic π 1 ( 1600 )

Le résumé fourni par la source

The spin-exotic hybrid meson ${\ensuremath{\pi}}_{1}(1600)$ is predicted to have a large decay rate to the $\ensuremath{\omega}\ensuremath{\pi}\ensuremath{\pi}$ final state. Using $76.6\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of data collected with the GlueX detector, we measure the cross sections for the reactions $\ensuremath{\gamma}p\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}p$, $\ensuremath{\gamma}p\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{0}p$, and $\ensuremath{\gamma}p\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\mathrm{\ensuremath{\Delta}}}^{++}$ in the range ${E}_{\ensuremath{\gamma}}=8--10\text{ }\text{ }\mathrm{GeV}$. Using isospin conservation, we set the first upper limits on the photoproduction cross sections of the ${\ensuremath{\pi}}_{1}^{0}(1600)$ and ${\ensuremath{\pi}}_{1}^{\ensuremath{-}}(1600)$. We combine these limits with lattice calculations of decay widths and find that photoproduction of ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\pi}$ is the most sensitive two-body system to search for the ${\ensuremath{\pi}}_{1}(1600)$.

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