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## Lattice QCD with chirally invariant fermions

### Krzysztof Michał Cichy

#### Abstract

The aim of this thesis was to investigate the mixed action setup of overlap valence and twisted mass sea quarks in Lattice QCD. This allowed to specify the regime of parameter values (i.e. lattice volume and pion mass) that allow to perform safe mixed-action simulations. In Chapter 1, theoretical principles of Lattice QCD are reviewed. The continuum QCD Lagrangian is introduced and its symmetries, in particular chiral symmetry, are discussed. Next, we show how the continuum theory is discretized and we introduce different fermion discretizations. Chapter 2 presents the results of a lattice spacing scaling test of different fermions at tree-level of perturbation theory. In Chapter 3 we discuss some of the technical details of QCD simulations. We review the HMC algorithm and the techniques used to effectively deal with overlap fermions. The main results of the thesis are reported in Chapter 4. The motivation and the general idea of a mixed action simulation are discussed. Then, a continuum limit scaling test of the pion decay constant is performed and the analysis of the role of chiral zero modes of the overlap operator is performed. In Chapter 5 we discuss some further results, including the unitarity violations present in the mixed action setup, light baryon masses computation and some topological aspects that can be probed with overlap fermions.
Record ID
UAM02bdd59190ed4740b464be62f40f001f
Diploma type
Doctor of Philosophy
Author
Title in Polish
Chromodynamika kwantowa na sieci z chiralnie niezmienniczymi fermionami
Title in English
Lattice QCD with chirally invariant fermions
Language
(en) English
Certifying Unit
Faculty of Physics (SNŚ/WyF/FoP)
Discipline
physics / (physical sciences domain) / (physical sciences)
Scientific discipline (2.0)
6.6 physical sciences
Status
Finished
Defense Date
15-10-2010
Title date
15-10-2010
Supervisor
URL
http://hdl.handle.net/10593/614 Opening in a new tab
Keywords in English
Lattice QCD, Chiral symmetry, Overlap discretization Twisted mass discretization
Abstract in English
The aim of this thesis was to investigate the mixed action setup of overlap valence and twisted mass sea quarks in Lattice QCD. This allowed to specify the regime of parameter values (i.e. lattice volume and pion mass) that allow to perform safe mixed-action simulations. In Chapter 1, theoretical principles of Lattice QCD are reviewed. The continuum QCD Lagrangian is introduced and its symmetries, in particular chiral symmetry, are discussed. Next, we show how the continuum theory is discretized and we introduce different fermion discretizations. Chapter 2 presents the results of a lattice spacing scaling test of different fermions at tree-level of perturbation theory. In Chapter 3 we discuss some of the technical details of QCD simulations. We review the HMC algorithm and the techniques used to effectively deal with overlap fermions. The main results of the thesis are reported in Chapter 4. The motivation and the general idea of a mixed action simulation are discussed. Then, a continuum limit scaling test of the pion decay constant is performed and the analysis of the role of chiral zero modes of the overlap operator is performed. In Chapter 5 we discuss some further results, including the unitarity violations present in the mixed action setup, light baryon masses computation and some topological aspects that can be probed with overlap fermions.
Thesis file
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Uniform Resource Identifier
https://researchportal.amu.edu.pl/info/phd/UAM02bdd59190ed4740b464be62f40f001f/
URN
urn:amu-prod:UAM02bdd59190ed4740b464be62f40f001f

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