  The properties of the strongly intensive variable characterizing correlations
between the number of particles in two separated rapidity interval in pp
interactions at LHC energies are studied in the framework of the string fusion
model. We perform the MC simulations of string distributions in the impact
parameter plane to take into account the experimental conditions of pp
collisions. We account the string fusion processes, leading to the formation of
string clusters, embedding a finite lattice (a grid) in the impact parameter
plane. As a result, we found the dependence of this variable both on the
distance between the centers of the observation windows and their width for the
minbias pp collisions at several initial energies. Analyzing these dependencies
we can extract the important information on the properties of string clusters.
We show that in pp collisions at LHC energies the string fusion effects have a
significant impact on the behavior of this strongly intensive variable. The
role of these effects is increasing with the initial energy and centrality of
collisions. In particular, we found that the increase of this variable with
initial energy takes place due to the growth of the portion of the fused string
clusters in string configurations arising in pp interactions.
