Hadron Production in Nuclear Deep Inelastic Scattering at HERMES

The influence of the cold nuclear medium on hadron production in semi-inclusive deep-inelastic scattering (SIDIS) was studied extensively by the Hermes experiment using a 27.6 GeV positron or electron beam. A series of measurements on deuterium, helium, neon, krypton and xenon targets has been performed in order to study quark propagation and hadronization. Hadron multiplicities on nucleus relative to those on deuteron, together with the first direct measurement of the hadron transverse momentum broadening in SIDIS, are presented.