QCD coherence and the soft limit of the energy spectrum
  The analytical perturbative approach, if taken to the limit of its applicability, allows one to predict an energy independent limit for the one-particle invariant density in QCD jets E dn/d^3p at very small momenta p. This is a direct consequence of the colour coherence in soft gluon branching. The existing data on the charged and identified particle inclusive spectra follow this prediction surprisingly well. Further tests of the perturbatively based picture in the soft region are discussed. 
V. A. Khoze (1,2), S. Lupia (3), W. Ochs (3) ((1) Univ. of Durham, (2)   Inst. Nucl. Phys., St. Petersburg, (3) Max-Planck-I...