Exploring extra dimensions through rare processes

Şimşek, Kağan
We study the single top quark production and decay mechanisms at one-loop level occurring via flavor-changing neutral currents in the Minimal Universal Extra Dimensions (MUED) model. We make a complete study of the model in the Feynman gauge. Especially, we focus on extracting the complete list of 3- and 4-point interactions and determining the mixings among the gauge eigenstates to form the so-called mass eigenstates. Once we have the complete model analyzed, it is implemented via the LanHEP package and transferred to specialized programs such as FeynArts, FormCalc, and LoopTools for automatic calculations. Finally, we explore the MUED predictions for rare top processes in detail and interpret our results.


Double-lepton polarization asymmetries and branching ratio of the B -> gamma l(+)l(-) transition in universal extra dimension
We study the radiative dileptonic B ->gamma l(+)l(-) transition in the presence of a universal extra dimension in the Applequist-Cheng-Dobrescu model. In particular, using the corresponding form factors calculated via light cone QCD sum rules, we analyze the branching ratio and double lepton polarization asymmetries related to this channel and compare the results with the predictions of the standard model. We show how the results deviate from predictions of the standard model at lower values of the compacti...
The mu -> e gamma and tau ->mu gamma decays in the general two Higgs doublet model with the inclusion of one universal extra dimension
Iltan, EO (2004-02-01)
We study the effect of one universal extra dimension on the branching ratios of the lepton flavor violating processes mu --> egamma and tau --> mugamma in the general two Higgs doublet model. We observe that these new effects are tiny for the small values of the compactification radius R. Furthermore, we see that these effects are comparable with the branching ratio obtained without including extra dimension, if the neutral Higgs bosons are nearly degenerate and the complexity of the Yukawa coupling, induci...
The effects of non-universal extra dimensions on the radiative lepton flavor decays mu -> e gamma and tau ->mu gamma in the two Higgs doublet model
Iltan, EO (2004-08-01)
We study the effect of non-universal extra dimensions on the branching ratios of the lepton flavor violating processes mu --> egamma and tau --> mugamma in the general two Higgs doublet model. We observe that these effects are small for a single extra dimension, however, in the case of two extra dimensions there is a considerable enhancement in the additional contributions.
Phase transition in compact QED3 and the Josephson junction
Onemli, VK; Tas, M; Tekin, Bayram (2001-08-01)
We study the finite temperature phase transition in 2+1 dimensional compact QED and its dual theory: Josephson junction. Duality of these theories at zero temperature was established long time ago in [1]. Phase transition in compact QED is well studied thus we employ the 'duality' to study the superconductivity phase transition in a Josephson junction. For a thick junction we obtain a critical temperature in terms of the geometrical properties of the junction.
Neutrino masses in the effective rank-5 subgroups of E-6. II. Supersymmetric case
Frank, M; Sher, M; Turan, İsmail (2005-06-01)
We present a complete analysis of the neutral fermion sector of supersymmetric E-6-inspired low-energy models containing an extra SU(2), concentrating on the alternative left-right and inert models. We show that the R-parity conserving scenario always exhibits a large Dirac mass for nu(L) with maximal mixing with an isosinglet neutrino, and that R-parity violating scenarios do not change the picture other than allowing further mixing with another isosinglet. In order to recover standard model phenomenology,...
Citation Formats
K. Şimşek, “Exploring extra dimensions through rare processes,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Physics., Middle East Technical University, 2019.