Sensitivity of the parameters measured in pp collisions on the gluon PDF

The sphericity distribution in minimum bias events obtained with PYTHIA event generator, incorporating different parton distribution functions is presented. The results show that for minimum bias pp collisions the sphericity distribution for different parameters like the mean transverse momentum and multiplicity exhibit strong sensitivity on the parton distribution function used. The results indicate that early data at the LHC could be used in this type of analysis to fix the gluon distribution function in the proton.