A Dilatonic Alternative

October 11, 2012

Who: Jens Krog (CP3-Origins)
When: Friday, October 12, 2012 at 15:00
Where: U44

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Jens F.C. Krog defends his master thesis on A Dilatonic Alternative. 

Jens’s thesis advisor is Francesco Sannino. Co-advisor Claudio Pica.

Abstract:

We put forth the conjecture that the recent findings at the LHC might indicate that the Higgs particle of electroweak physics is a so-called dilaton; a pseudo-Goldstone boson of a broken conformal symmetry. We then go on to show how the onset of symmetry breaking appears in massless theories of any number of scalars from quantum corrections where we through the effective potential and the balancing of gauge or quartic couplings may ensure spontaneous symmetry breaking. An additional analysis using the renormalization group equations and the improved couplings is discussed, and the possibility of a geometrical picture to investigate the phase structure of a theory is presented. A specific near conformal theory featuring non-trivial fixed point structure is investigated, and a light scalar is shown to be a dilaton, which can be tuned to have arbitrarily small mass without making the theory noninteracting. We then investigate which effects an electroweak SU (2) × U (1) sector has on the features of the theory. We find that if the number of flavors and colors in the theory are chosen carefully, then the theory will be virtually unaffected by the new interactions, but if parameters are chosen differently the conformal phase of the original theory becomes hidden, because the theory can never reach a fixed point. We show that this specific implementation of the electroweak sector renders it difficult to reach a realistic spectrum and inside the perturbative region. We relate the theory discussed to technicolor theories and review recent phenomenological studies of LHC data in this context.

The thesis is available as a PDF file.