Mid-rapidity dependence of pion production in $$p-p$$p-p and $$A-A$$A-A collisions.

The calculation of inclusive spectra of pions produced in pp and AA collisions as functions of the rapidity y is presented within the self-similarity approach. It is shown that at not too large rapidities y one can obtain an analytical form of the self-similarity function $$\varPi (y,p_t)$$ dependent on y and on the hadron transverse momentum $$p_t$$. A satisfactory description of the data on rapidity spectra at $$|y|\le $$ 0.3 is presented within the approach applied. The energy dependence of these spectra is also shown to be universal.