Upsilon Spectroscopy Using Lattice QCD

McCallum, Paul (1997) Upsilon Spectroscopy Using Lattice QCD. PhD thesis, University of Glasgow.

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The non-relativistic QCD theory developed by the NRQCD collaboration is employed in simulations reproducing the upsilon spectrum. Correlations are analysed using multi-correlation fitting routines yielding energies and amplitudes. Good reproduction of the experimental upsilon spectrum is found with statistical errors comparable with systematic errors. The effects of three such systematic errors, lattice spacing, truncation of the relativistic expansion and quenching, are investigated. Radial and orbital splittings are found to have lattice spacing errors and truncation errors that are much smaller than statistical errors. These splittings give good to excellent agreement with experiment on the removal of quenching errors. Spin splittings and the wavefunction at the origin are found to have large lattice spacing, truncation and radiative correction errors which are of the order of 10%, comparable with statistical errors. These quantities give reasonable agreement with experiment on the removal of quenching errors and a prediction for the S state hyperfine splitting of 41(6) MeV is obtained. The method developed by the NRQCD collaboration to obtain the strong coupling constant in the MS scheme at the Z0 mass is followed with lattice spacings determined from the upsilon radial and orbital splittings used to scale the coupling values. A best value of 0.1171(23) was obtained for this coupling. Sources of systematic error affecting this value are investigated and are found to be at the few percent level.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: Christine Davies
Keywords: Theoretical physics
Date of Award: 1997
Depositing User: Enlighten Team
Unique ID: glathesis:1997-74663
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 27 Sep 2019 17:18
Last Modified: 27 Sep 2019 17:18

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