Study of factorial moments and intermittency in pp collisions at [special characters omitted]= 13 TeV

Date of Award

Spring 2016

Document Type


Degree Name

Doctor of Philosophy (PhD)


Engineering Physics

First Advisor

Lee Sawyer


Modeling of the charged-particle multiplicity dependence on transverse momentum, pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are presented for pp collisions at center of mass energy [special characters omitted]= 13 TeV with two different Monte Carlo event generators, Pythia 8 and Herwig++ 2.7.1, including studies of light quarks and heavy quarks, tt production. The results are achieved with charged particles with transverse momentum larger than 500 MeV and absolute pseudorapidity less than 3, in events with at least one charged particle, and in events with at least six charged particles filling these kinematic requirements.

Intermittency studyies the distributions of particles in the phase-space regions to analyze the dynamics of hadroproduction. Intermittency is an increase of factorial moments with decreasing bin size, where dynamical fluctuations are noticed.

In this dissertation, the study of intermittency phenomena and correlations of multiplicities of charged particles in one-dimensional phase-space of rapidity are presented. The aim of this analysis is to study the dynamical correlations of many-particle systems that are produced in pp collisions carried out at higher energies, where one cannot separate lower-order correlations from higher-order correlations. Theoretical approaches do not explain the origin of the dynamical fluctuations. The behaviors of particle distributions that are intermittent provide a strong test of QCD. The interactions with a small number of very hard scattering processes is more sensitive to multi-particle correlations. The structure of the cascade of the gluon-quark fragmentation characterizes multifractal shapes of the multi-particles by Renyi dimensions D q which depend on the rank q.