  Taking into account the anisotropy of phase space in multiparticle
production, a self-affine analysis of factorial moments was carried out on the
NA22 data for $\p^+\Pp$ and $\PK^+\Pp$ collisions at 250 GeV/$c$. Within the
transverse plane, the Hurst exponents measuring the anisotropy are consistent
with unit value (i.e. no anisotropy). They are, however, only half that value
when the longitudinal direction is compared to the transverse ones. Fractality,
indeed, turns out to be self-affine rather than self-similar in multiparticle
production. In three-dimensional phase space, power-law scaling is observed to
be better realized in self-affine than in self-similar analysis.

High Energy Physics - Experiment