Q-meson system in diffractive processes

We present a unitary, analytic coupled-channel model for diffractive production of the $Q$-meson system in $\mathrm{Kp}\to \mathrm{Qp}$, with $Q\to K^{*}\pi$ and $Q\to \rho K$. Our model includes well-defined nonresonant Deck amplitudes in states of $t$-channel helicities both one and zero. We obtain excellent fits to the high-statistics SLAC data at 13 GeV/c. We confirm the existence of two resonances, $Q_1$ and $Q_2$, with parameters $M_1=1.28\mathrm{}\pm 0.02$ GeV, $70<\mathrm{}{\Gamma }_1^{\mathrm{tot}}<140\mathrm{}$ MeV; $M_2=1.42\mathrm{}\pm 0.06$ GeV, ${\Gamma }_2^{\mathrm{tot}}=230\mathrm{}\pm 50$ MeV. The $Q_1$ is coupled mainly to $\rho K$ and the $Q_2$ to $K^{*}\pi$.