New Constraints from Haverah Park Data on the Photon and Iron Fluxes of Ultrahigh-Energy Cosmic Rays

Using data from inclined events ( $60°<\theta <80\mathrm{}°$) recorded by the Haverah Park shower detector, we show that above ${10}^{19}\mathrm{eV}$ less than $41\%$ ( $54\%$) of the primary cosmic rays can be photons (iron nuclei) at the $95\%$ confidence level. Above $4\times {10}^{19}\mathrm{eV}$ less than $65\%$ of the cosmic rays can be photonic at the same confidence level. These limits place important constraints on some models of the origin of ultrahigh-energy cosmic rays. Details of two new events above ${10}^{20}\mathrm{eV}$ are reported.