Search for the exotic Ξ––(1860) resonance in 340 GeV/c Σ –-nucleus interactions

We report on a high statistics search for the ${\\ensuremath{\\Xi}}^{\\ensuremath{-}\\ensuremath{-}}(1860)$ resonance in ${\\ensuremath{\\Sigma}}^{\\ensuremath{-}}$-nucleus collisions at $340\\phantom{\\rule{0.3em}{0ex}}\\mathrm{GeV}∕c$. No evidence for this resonance is found in our data sample which contains 676000 ${\\ensuremath{\\Xi}}^{\\ensuremath{-}}$ candidates above background. For the decay channel ${\\ensuremath{\\Xi}}^{\\ensuremath{-}\\ensuremath{-}}(1860)\\ensuremath{\\rightarrow}{\\ensuremath{\\Xi}}^{\\ensuremath{-}}{\\ensuremath{\\pi}}^{\\ensuremath{-}}$ and the kinematic range $0.15l{x}_{F}l0.9$ we find a $3\\ensuremath{\\sigma}$ upper limit for the production cross section of 3.1 and $3.5\\phantom{\\rule{0.3em}{0ex}}\\ensuremath{\\mu}\\mathrm{b}$ per nucleon for reactions with carbon and copper, respectively.