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Non-zero temperature charmonium potentials from the lattice. / P. Wynne M Evans
Swansea University Author: P. Wynne M Evans
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Abstract
A reliable calculation of the charmonium potential at non-zero temperature from first principles is required as part of a wider effort to understand the phase transition of hadronic matter to quark-gluon plasma at high temperature. The interquark potential inside hot matter produced in heavy ion col...
| Published: |
2014
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| Institution: | Swansea University |
| Degree level: | Doctoral |
| Degree name: | Ph.D |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa42456 |
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| Abstract: |
A reliable calculation of the charmonium potential at non-zero temperature from first principles is required as part of a wider effort to understand the phase transition of hadronic matter to quark-gluon plasma at high temperature. The interquark potential inside hot matter produced in heavy ion collisions can not be measured directly. Therefore the precise role of the intcrquark potential in quark-gluon plasma formation can currently only be determined through a reliable theoretical calculation. In this thesis charmonium potentials are obtained from dynamical lattice simulations of quantum chromodynamics by analysing correlators using two different approaches; i) conventional fitting - correlators are fitted in the conventional manner familiar from hadron spectroscopy on the lattice; ii) the HAL QCD time-dependent method - a novel technique borrowed from nuclear physics is used to derive an expression for the potential directly in terms of the correlators. Recent lattice QCD studies relevant to the charmonium potential fall into two categories: i) non-zero temperature studies of the static quark potential; ii) zero temperature studios with i)hysical charm masses. The results presented in this thesis are novel because they are from a study of the charnionium potential using physical charm masses at non-zero temperature. The charmonium potential obtained from conventional fitting is found to be temperature dependent, as the temperature increases, the potential flattens. However the method suffers from certain reliability issues. The time-dependent method is found to be more suitable than conventional fitting for studying the interquark potential at high temperature. Using the time-dependent method the charmonium potential between 0.76Tc and 1.09Tc is found to be temperature dependent. The result is reliable and shows the potential flattening as the temperature increases, which is consistent with the expectation that at high temperature the interquark potential becomes colour-Debye screened. Extracting the potential from temperatures higher than 1.09Tc would have led to unreliable results, but this limit is specific to the configurations used and not the method itself. The study shows that if configurations are generated with the time-dependent method in mind, then it can be used to extract the charmonium potential at temperatures higher than 1.09Tc. |
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| Keywords: |
Theoretical physics. |
| College: |
Faculty of Science and Engineering |