[en] The charged particle asymmetry, (n⁺-n^-)/(n⁺+n^-), in inclusive photoproduction of charged particles on protons has been studied as a function of x_F and p_T in the ranges x_F>0 and 0< p_T<2 GeV/c and for photon energies in the range 65< E_γ<175 GeV. The asymmetry is found to be positive and decreasing with E_γ. Asymmetries of π's and K's in the final state have been obtained separately. Data from a carbon target show a significantly lower asymmetry. These results have been compared with a parton recombination model which provides a qualitative explanation for the asymmetry and its x_F and E_γ dependences. The model also gives a qualitative understanding of the lower asymmetry seen with the nuclear target. (orig.)

[en] Inclusive production of φ, K*⁰, and anti K*⁰ mesons has been measured in γp, π^±p and K^±p collisions at beam energies of 65 GeV< E_γ<175 GeV and E_π/K=80 and 140 GeV. Cross sections have been determined over the range 0< x_F<1.0 and 0< P_T<1.8 GeV/c. Emphasis is put on the comparison of cross sections for different projetiles as a function of x_F so as to study the effects of common quarks between the beam particle and the detected φ, K*⁰ or anti K*⁰. The data are compared with a parton fusion model. Many features of the data are well explained. In detail the strange quark appears to carry a large fraction of the kaon momentum and the contribution of the valence quarks from the proton is small. (orig.)

No abstract available