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Upper Limits on Cross Sections for γ + n → K 0 + Λ 0 ( Σ</…

1967; American Institute of Physics; Volume: 157; Issue: 5 Linguagem: Inglês

10.1103/physrev.157.1259

1536-6065

D.G. Coyne, Joe H. Mullins,

Particle physics theoretical and experimental studies

A search for the reactions $\ensuremath{\gamma}+n\ensuremath{\rightarrow}{K}^{0}+\ensuremath{\Lambda}$ and $\ensuremath{\gamma}+n\ensuremath{\rightarrow}{K}^{0}+{\ensuremath{\Sigma}}^{0}$ has been conducted using the Cal Tech heavy-liquid bubble chamber as the detector with a central internal target. Photon energies were from threshold to 1530 MeV. The absence of any real events in 14 000 pictures implies a joint upper limit on the average total cross sections ${\overline{\ensuremath{\sigma}}}_{\ensuremath{\Lambda}}$ and ${\overline{\ensuremath{\sigma}}}_{\ensuremath{\Sigma}}$ in this energy region. If the ratio $\frac{{\overline{\ensuremath{\sigma}}}_{\ensuremath{\Lambda}}}{{\overline{\ensuremath{\sigma}}}_{\ensuremath{\Sigma}}}$ is near unity, we find at the 90% confidence level: ${\overline{\ensuremath{\sigma}}}_{\ensuremath{\Lambda}}\ensuremath{\le}2.4$ \ensuremath{\mu}b, ${\overline{\ensuremath{\sigma}}}_{\ensuremath{\Sigma}}\ensuremath{\le}2.1$ \ensuremath{\mu}b.