Upper limits for charm production in 150 GeV p-Be interactions

A search has been made for the hadronic production of charmed baryons and mesons with a large aperture forward magnetic spectrometer using 150 GeV protons originating from the CERN-SPS. A prompt electron trigger was used as a signature for charm. Upper limits at 90% confidence level have been obtained for the production of $\text{Λ}{}_{\mathrm{<mtext>c</mtext>}}{}^{\mathrm{+}}\text{D}{}^0\text{,}\text{D}{}^0\text{D}{}^{\mathrm{+}}\text{and D}{}^{\mathrm{?}}\text{: σ(Λ}{}_{\mathrm{<mtext>c</mtext>}}\text{) ? 8 μ}\text{b}\text{, σ(}\text{D}{}^0\text{) ? 64 μ}\text{b}\text{, σ(}\text{D}{}^0\text{) < 37 μ}\text{b}\text{, σ(}\text{D}{}^{\mathrm{+}}\text{) ? 51 μ}\text{b and}\text{σ(}\text{D}{}^{\mathrm{?}}\text{) ? 49 μ}\text{b}$ per nucleon, assuming linear A dependence. Systematic errors due to uncertainties in branching ratios and to model dependence of the acceptance calculation are discussed.