Abstract:
The cross-section calculation for exclusive J /Ψ vector-meson production in ultra-peripheral heavy ion collisions is approached in two ways. First, the setup for a theoretical calculation is done in the context of the Colour Glass Condensate effective field theory. Rapidity-averaged n-point correlators are used to describe the strong interaction part of this process. The JIMWLK equation can be used to predict the energy evolution of a correlator. In order to facilitate practical calculations, an approximation scheme must be employed. The Gaussian Truncation is one such method, which approximates correlators in terms of new 2-point functions. This work takes the first step beyond this truncation scheme by considering higher-order n-point functions in the approximation. An expression for the cross-section is written, which takes parametrised 2- and 4-point correlators as input. This expression can be used as the basis for a full cross-section calculation. The second part of the thesis is a feasibility study using Monte Carlo simulations done by the STARlight event generator. A prediction is made for how many exclusive J /Ψ vector-mesons are expected to be detected by ATLAS in a data set corresponding to 160 μb−1 total integrated luminosity. It is found that the muon reconstruction efficiencies for low pT muons is too poor in ATLAS to do this analysis effectively. On the order of 150 candidate events are expected from all the Pb-Pb collision data collected in 2011. The feasibility study acts as a preliminary investigation for a full cross-section measurement using ATLAS collision data. Once this is completed, it can be compared with the theoretical prediction for the cross-section.

Reference:
Ramnath, A. 2014. Exclusive J/Ψ Vector-Meson production in high-energy nuclear collisions: a cross-section determinaton in the Colour Glass Condensate effective field theory and a feasibility study using the STARlight Monte Carlo event generator. University of Cape Town.

Includes bibliographical references.