Calculation of the axial charge of a heavy nucleon in Lattice QCD

In this thesis, we aim to calculate the non-renormalized axial charge gA of a heavy nucleon made out of quarks at the physical mass of the strange quark. We present the framework of Lattice QCD which makes the calculation of such observables attainable from first principles. The data used for the estimation of gA were obtained on a 243 x64 hypercubic lattice with lattice spacing a ~ 0.12 fm and pion mass m[pi] = 0.450 GeV. Three different source-sink seperations were used, tsink = [12a, 14a, 16a]. For each timeslice seperation signal we perform a correlated x2 fit and obtain the following values for gA: 0.551, 0.564 and 0.556. The unrenormalized value value for gA is extracted taking the limit as tsink --> [infinity] and is shown to be gA = 0.558. We discuss how the accuracy of this result is compromised by the small number of tsink values, by excited state contamination and by the increase of statistical noise with time.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2016

Author dc:creator

• Pefkou, Dimitra Anastasia

Advisor dc:contributor.advisor

• William Detmold.

• Physics.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/111890

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/111890