The structure function ratios F2C/F2Li, F2Ca/F2Li and F2Ca/F2C were measured in deep inelastic muon-nucleus scattering at an incident muon energy of 90 GeV, covering the kinematic range 0.0085 < x < 0.6 and 0.8 < Q2 < 17 GeV2. The sensitivity of the nuclear structure functions to the size and mean density of the target nucleus is discussed.

We present the structure function ratios F2He/F2D, F2C/F2D and F2Ca/F2D measured in deep inelastic muon-nucleus scattering at an incident muon momentum of 200 GeV. The kinematic range 0.0035 < x < 0.65 and 0.5 < Q2 < 90 GeV2 is covered. At low x the three ratios are significantly smaller than unity and the size of the depletion grows with decreasing x and increasing mass number A. At intermediate x the ratios show an enhancement of about 2% above unity for C/D and Ca/D, possibly less for He/D. There are indications of some Q2 dependence in the Ca/D data. The integrals of the structure function differences F2A-F2D are discussed.

We have studied transverse momentum distributions for exclusive rho(0) muoproduction on protons and heavier nuclei at 2 < Q2 < 25 GeV2. The Q2 dependence of the slopes of the p(t)2 and t' distributions is discussed. The influence of the non-exclusive background is investigated. The p(t)2-slope for exclusive events is 4.3 +/- 0.6 +/- 0.7 GeV-2 at large Q2. The p(t)2 spectra are much softer than inclusive p(t)2 spectra of leading hadrons produced in deep inelastic scattering.

Data are presented on exclusive ρ^{0} and φ{symbol} production in deep inelastic muon scattering from a target consisting mainly of nitrogen. The ratio of the total cross sections for ρ^{0} and φ{symbol} production is found to be 9:(1.6±0.4) at 〈Q^{2}〉=7.5 GeV^{2}, consistent with the SU(3) prediction of 9:2. The t dependence for exclusive ρ^{0} production is found to become shallover as Q^{2} increases and, for large Q^{2}, the t dependence is typical of that for a hard scattering process. Furthermore, the ratio of the cross sections for coherent: incoherent production from nitrogen is found to decrease rapidly with Q^{2}. Such behaviour indicates that even for exclusive vector meson production the virtual photon behaves predominantly as an electromagnetic probe.

Results are presented on the ratios of the nucleon structure function in copper to deuterium from two separate experiments. The data confirm that the nucleon structure function, F2, is different for bound nucleons than for the quasi-free ones in the deuteron. The redistribution in the fraction of the nucleon's momentum carried by quarks is investigated and it is found that the data are compatible with no integral loss of quark momenta due to nuclear effects.

Final data measured with the EMC forward spectrometer are presented on the production of forward charged hadrons in mu-p and mu-d scattering at incident beam energies between 100 and 280 GeV. The large statistic of 373000 events allows a study of the semi-inclusive hadron production as a function of z, p(T)2 and <p(T)2> in small Q2, x(Bj) and W bins. Charge multiplicity ratios and differences as a function of z and x(Bj) are given for p, d and n-targets. From the differences of charge multiplicities the ratio of the valence quark distributions of the proton d-upsilon(x)/u-upsilon(x) is determined for the first time in charged lepton scattering. The Gronau et al. sum rule is tested, the measured sum being 0.31 +/- 0.06 stat. +/- 0.05 syst., compared with the theoretical expectation of 2/7 almost-equal-to 0.286. The measured sum corresponds to an absolute value of the ratio of the d and u quark charge of 0.44 +/- 0.10 stat. +/- 0.08 syst.

Measurements are presented of the inclusive distributions of the J/psi meson produced by muons of energy 200 GeV from an ammonia target. The gluon distribution of the nucleon has been derived from the data in the range 0.04 < x < 0.36 using a technique based on the colour singlet model. An arbitrary normalisation factor is required to obtain a reasonable integral of the gluon distribution. Some comments are made on the use of J/psi production by virtual photons to extract the gluon distribution at HERA.