  The quark-gluon plasma formed as a result of heavy-ion collisions is
currently investigated actively both theoretically and experimentally.
According to the holographic approach, forming a quark-gluon plasma in the
four-dimensional world is associated with creating black holes in a
five-dimensional anti-de Sitter space. The multiplicity of particles produced
in heavy-ion collisions is then determined by the entropy of the
five-dimensional black hole, which is estimated by the area of the trapped
surface. To fit the experimental data for multiplicity Kiritsis and Taliotis
have proposed to consider black holes formation in modified ${AdS}_5$ spaces
with different $b$-factors. In this paper we consider the formation of black
holes under collision of membranes in modified ${AdS}_5$ spaces with
$b$-factors. Following the previous proposals we consider the power-law and
exponential $b$-factors, as well as mixed types of $b$-factors. We study
dynamics of the change of the trapped surface area depending on the energy for
each investigated space. We find that the power-law and mixed factors fit
better to the experimental date.
