The early universe as a probe of new physics

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dc.contributor.author Bird, Christopher Shane
dc.date.accessioned 2008-12-05T00:33:34Z
dc.date.available 2008-12-05T00:33:34Z
dc.date.copyright 2008 en_US
dc.date.issued 2008-12-05T00:33:34Z
dc.identifier.uri http://hdl.handle.net/1828/1274
dc.description.abstract The Standard Model of Particle Physics has been verified to unprecedented precision in the last few decades. However there are still phenomena in nature which cannot be explained, and as such new theories will be required. Since terrestrial experiments are limited in both the energy and precision that can be probed, new methods are required to search for signs of physics beyond the Standard Model. In this dissertation, I demonstrate how these theories can be probed by searching for remnants of their effects in the early Universe. In particular I focus on three possible extensions of the Standard Model: the addition of massive neutral particles as dark matter, the addition of charged massive particles, and the existence of higher dimensions. For each new model, I review the existing experimental bounds and the potential for discovering new physics in the next generation of experiments. For dark matter, I introduce six simple models which I have developed, and which involve a minimum amount of new physics, as well as reviewing one existing model of dark matter. For each model I calculate the latest constraints from astrophysics experiments, nuclear recoil experiments, and collider experiments. I also provide motivations for studying sub-GeV mass dark matter, and propose the possibility of searching for light WIMPs in the decay of B-mesons and other heavy particles. For charged massive relics, I introduce and review the recently proposed model of catalyzed Big Bang nucleosynthesis. In particular I review the production of Li6 by this mechanism, and calculate the abundance of Li7 after destruction of Be7 by charged relics. The result is that for certain natural relics CBBN is capable of removing tensions between the predicted and observed Li6 and Li7 abundances which are present in the standard model of BBN. For extra dimensions, I review the constraints on the ADD model from both astrophysics and collider experiments. I then calculate the constraints on this model from Big Bang nucleosynthesis in the early Universe. I also calculate the bounds on this model from Kaluza-Klein gravitons trapped in the galaxy which decay to electron-positron pairs, using the measured 511 keV gamma-ray flux. For each example of new physics, I find that remnants of the early Universe provide constraints on the models which are complimentary to the existing constraints from colliders and other terrestrial experiments. en_US
dc.language English eng
dc.language.iso en en_US
dc.rights Available to the World Wide Web en_US
dc.subject cosmology en_US
dc.subject dark matter en_US
dc.subject extra dimensions en_US
dc.subject Big Bang Nucleosynthesis en_US
dc.subject early Universe en_US
dc.subject astrophysics en_US
dc.subject catalyzed nuclear fusion en_US
dc.subject Big Bang model en_US
dc.subject.lcsh UVic Subject Index::Sciences and Engineering::Physics en_US
dc.title The early universe as a probe of new physics en_US
dc.type Thesis en_US
dc.contributor.supervisor Pospelov, Maxim
dc.degree.department Dept. of Physics and Astronomy en_US
dc.degree.level Doctor of Philosophy Ph.D. en_US

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