  Charged particle production has been measured in deep inelastic scattering
(DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The
evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280
$GeV^2$, has been investigated in the current fragmentation region of the Breit
frame. The results show clear evidence, in a single experiment, for scaling
violations in scaled momenta as a function of $Q^2$.

High Energy Physics - Experiment