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CP violation in QCD, axions and possible connections to dark matter

Corrigan, Eric LU (2013) FYSK01 20122
Department of Physics
Abstract
The strong CP problem and its solution are treated on the undergraduate level. We first review the theoretical background of symmetry and symmetry breaking in particle physics. The Goldstone model is treated for several simple systems: the linear sigma model, the Higgs mechanism and the interpretation of pions as pseudo-Goldstone bosons in QCD. The problem of lack of CP-violation in strong interactions is explained, and the most popular solution---the addition of an additional $U(1)_{\mathrm{PQ}}$-symmetric field and its quanta, the axion---is presented. The current experimental status of the axion is detailed, including limits set by laboratory and astrophysical searches. Finally, the axion in the context of its possible role as a dark... (More)
The strong CP problem and its solution are treated on the undergraduate level. We first review the theoretical background of symmetry and symmetry breaking in particle physics. The Goldstone model is treated for several simple systems: the linear sigma model, the Higgs mechanism and the interpretation of pions as pseudo-Goldstone bosons in QCD. The problem of lack of CP-violation in strong interactions is explained, and the most popular solution---the addition of an additional $U(1)_{\mathrm{PQ}}$-symmetric field and its quanta, the axion---is presented. The current experimental status of the axion is detailed, including limits set by laboratory and astrophysical searches. Finally, the axion in the context of its possible role as a dark matter (DM) candidate is reviewed, focusing primarily on the theory of axionic cold dark matter and its status. We find that the axion is an appealing solution to the CP problem, and a highly viable candidate for cold dark matter in the Universe. (Less)
Please use this url to cite or link to this publication:
author
Corrigan, Eric LU
supervisor
organization
course
FYSK01 20122
year
type
M2 - Bachelor Degree
subject
keywords
QCD, axions, CP violation, dark matter, symmetry breaking
language
English
id
4281318
date added to LUP
2014-03-26 13:11:31
date last changed
2014-03-26 13:11:31
@misc{4281318,
  abstract     = {{The strong CP problem and its solution are treated on the undergraduate level. We first review the theoretical background of symmetry and symmetry breaking in particle physics. The Goldstone model is treated for several simple systems: the linear sigma model, the Higgs mechanism and the interpretation of pions as pseudo-Goldstone bosons in QCD. The problem of lack of CP-violation in strong interactions is explained, and the most popular solution---the addition of an additional $U(1)_{\mathrm{PQ}}$-symmetric field and its quanta, the axion---is presented. The current experimental status of the axion is detailed, including limits set by laboratory and astrophysical searches. Finally, the axion in the context of its possible role as a dark matter (DM) candidate is reviewed, focusing primarily on the theory of axionic cold dark matter and its status. We find that the axion is an appealing solution to the CP problem, and a highly viable candidate for cold dark matter in the Universe.}},
  author       = {{Corrigan, Eric}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{CP violation in QCD, axions and possible connections to dark matter}},
  year         = {{2013}},
}