Browsing by Subject "Rapidity"
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Item The differential shape of the Z to ee cross-section as a function of Z rapidity(2011-05) Haupt, Jason AnthonyBefore the LHC discovers new physics and new particles, the detectors needed to undergo commissioning. The detection and measurement of Standard Model processes was one way to validate the detector response. Some benefits of the validation procedure were accurate predictions of signals and backgrounds. The rapidity shape of the Z boson was used as a probe into the Probability Distribution Functions of the proton. This thesis discusses the differential Z cross-section measurement with 36 pb^-1 of integrated luminosity acquired at the LHC on the CMS detector in 2010 at a center of mass of 7 TeV.Item Initial energy density in heavy ion collisions from a color neutral three-dimensional color glass condensate model of QCD(2013-08) Ozonder, SenerIn the ultrarelativistic heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC), Brookhaven National Lab (BNL) and the Large Hadron Collider (LHC), CERN, hot, dense and strongly interacting Quark Gluon Plasma has been created. After the Quark Gluon Plasma reaches local thermal equilibrium, the fireball expands rapidly. Relativistic hydrodynamics successfully captures this evolution given the initial energy and initial entropy densities, along with the equation of state. This is followed by freeze-out of the plasma into hadrons, which are finally recorded at the detectors. The final multiplicity of the detected particles as well as their distribution in transverse momentum and rapidity are determined by the initial conditions of the hydrodynamic evolution of the Quark Gluon Plasma. In this thesis, the initial energy density of heavy-ion collisions is calculated in the framework of an effective model based on Quantum Chromodynamics. An overview of heavy ion collisions and Quark Gluon Plasma is given first. Then, the three-dimensional, color neutral McLerran-Venugopalan model is introduced and its parameters are fixed from the data on gluon distribution functions. Finally, we apply this model to Au-Au (at RHIC) and Pb-Pb (at LHC) collisions to calculate the initial energy density. The most important result of the work presented here is calculation of the rapidity profile of the initial energy density. Finally we compare our results on the energy density profile with that is used in hydrodynamic simulations.