Hadronic decay of theetac(2980)

From a study of 2.7×${10}^6$ J/ψ decays with the Mark III detector at the SLAC storage ring SPEAR, we determine branching ratios for decays of the ${\eta }_c$ to η${\pi }^{+}$ ${\pi }^{\mathrm{-}}$, ${\pi }^{\pm }$ $K^{\mp }$ $K_S$, ${\pi }^{+}$ ${\pi }^{\mathrm{-}}$ ${\pi }^{+}$ ${\pi }^{\mathrm{-}}$, ${\pi }^{+}$ ${\pi }^{\mathrm{-}}$ $K^{+}$ $K^{\mathrm{-}}$, pp¯, the previously unobserved modes η’ ${\pi }^{+}$ ${\pi }^{\mathrm{-}}$, ${\pi }^0$ $K^{+}$ $K^{\mathrm{-}}$, K¯ ${}_{}{}^{\mathrm{*}0}{}_{}{}^{}K_{}^{\pm }{}_{}{}^{}$ ${\pi }^{\mp }$, $K^{\mathrm{*}0}$K¯ ${}_{}{}^{\mathrm{*}0}{}_{}{}^{}$, and new upper limits on ρρ, ωω, δπ, $A_2$π, fη, and ηKK. When combined, the different measurements of the ${\eta }_c$ mass yield 2980.2±1.6 MeV/$c^2$. In the decays ${\eta }_c$→vector+vector, a strong increase of the decay rate with the number of strange quarks in the final state is observed.