Polarized deep inelastic scattering (DIS) experiments indicate that quarks only carry approximately 30% of the proton spin, which led to interest in measuring the contributions of other components. Through polarized proton-proton collisions at the Relativistic Heavy Ion Collider (RHIC), the world's only polarized proton collider, it is possible to make an extraction of the polarized gluon distribution function [delta]g(x). This function describes the contribution of the gluon polarization to the proton spin. This thesis presents a measurement of the p + p ---> Jet + Jet + X (dijet) cross section from the 2005 RHIC running period and a measurement of the longitudinal double spin asymmetry ALL from the 2009 RHIC running period, both made using the Solenoidal Tracker at RHIC (STAR). The cross section is measured over the invariant mass range 20

The inclusive jet cross section, the dijet cross section, and the dijet longitudinal double spin asymmetry ALL in polarized proton-proton collisions at [square root of sigma] = 200 GeV are measured with a data sample of 5.4 pbm collected with the STAR detector during RHIC Run-6. The inclusive cross section is measured as a function of jet transverse momentum PT in the range of 10

We present the Inclusive Jet Longitudinal Double-Spin Asymmetry for polarized protons at \s = 200 GeV. The data were taken on the STAR experiment at RHIC during the 2005 run period and cover a jet transverse momentum range of 5

High-pT processes in proton- and deuteron-nucleus collisions at TeV energies are the best presently available way to study the partonic structure of the nucleus in a high-density regime. Jet production over a wide range of phase space can significantly constrain the current knowledge of nuclear parton distribution functions (nPDFs), which are substantially less well understood than the corresponding PDFs in protons and which have only recently begun to be treated in a spatially-dependent way. An accurate knowledge of nPDFs is crucial for a definitive control of perturbative processes in a cold nuclear environment, since high-pT probes are used to quantitatively investigate the hot QCD matter created in ultrarelativistic nucleus-nucleus collisions. Furthermore, jets from low Bjorken-x partons can probe the transition from the dilute to saturated nuclear regimes.

The jet production in proton-proton, proton-nucleus and nucleus-nucleus collisions at relativistic and ultrarelativistic energies using the HIJING is studied and discussed. We analyzed the distributions of multiplicity of secondary charged particles, their pseudorapidity, rapidity and the transverse mass as a function of the number of jets. These parameters are used to estimate energy density and temperature of the hadronic matter to get the signal about QGP formation. For ultrarelativistic energy we considered pp at 14 TeV, PbPb at 5.5 TeV, pPb at 8.8 TeV and ArAr at 6.3 TeV, same as in ALICE and also at 25.0 GeV as relativistic energy. We obtained some insights about some properties of jets and their influences on the characteristics of the secondary particles produced in relativistic and ultrarelativistic hadronic collisions. In this text the background information about the jet production is presented in chapter 1. Chapter 2 contains description of the HIJING parameters. Chapter 3 is a description of the ALICE detectors. The results obtained by using the HIJING for pp, pA and AA interactions are presented and discussed in Chapter 4. Chapter 5 summarizes the conclusions.