Measurements of Ξ_c⁺ branching ratios

Using data collected by the fixed target Fermilab experiment FOCUS, we measure the branching ratios of the Cabibbofavored decays Ξ_c ⁺ → Σ⁺K^-π⁺, Ξ _c⁺ → Σ⁺K̄*(892) ⁰, and Ξ_c⁺ → ∧⁰K ^-π⁺π⁺ relative to Ξ_c ⁺ → Ξ^-π⁺π⁺ to be 0.91 ± 0.11 ± 0.04, 0.78 ± 0.16 ± 0.06, and 0.28 ± 0.06 ± 0.06, respectively. We report the first observation of the Cabibbo-suppressed decay Ξ_c⁺ → Σ ⁺K⁺K^- and we measure the branching ratio relative to Ξ_c⁺ → Σ⁺K ^-π⁺ to be 0.16 ± 0.06 ± 0.01. We also set 90% confidence level upper limits for Ξ_c⁺ → Σ⁺φ and Ξ_c⁺ → Ξ*(1690)⁰(Σ⁺K^-)K⁺ relative to Ξ_c⁺ → Σ⁺K ^-π⁺ to be 0.12 and 0.05, respectively. We find an indication of the decays Ξ_c⁺ → Ω ^-K⁺π⁺ and Ξ_c⁺ → Σ*(1385)⁺K̄⁰ and set 90% confidence level upper limits for the branching ratios with respect to Ξ _c⁺ → Ξ^-π⁺π ⁺ to be 0.12 and 1.72, respectively. Finally, we determine the 90% C.L. upper limit for the resonant contribution Ξ_c⁺ → Ξ*(1530)⁰π⁺ relative to Ξ _c⁺ → Ξ^-π⁺π ⁺ to be 0.10.