  We formulate empirically the rapidity density distribution of produced
particles in multiple particle production. The assumed mechanism is that the
produced particles are emitted isotropically from several emitting centers,
located on the rapidity axis. The formula includes five adjustable parameters,
which are to be determined by the experimental data of (pseudo-)rapidity
density distributions and transverse momentum distributions at various
energies. It is a distinguished difference of the present rapidity density
distribution from those of other models that the particle production is
suppressed strongly in the forward region. We discuss multiplicity and
inelasticity at high energies, the pseudo-rapidity density distribution at LHC
energy and some speculations, based on the present formulation.
