Higgs Effects in Neutrino Physics and Heavy Quark Systems
May, 2014274 pages
Supervisor:
Thesis: PhD - Alakabha Datta()
- Mississippi U.
ISBN:
- 9781321047011 (Print)
- Published: 2014
Report number:
- AAT-3628587
View in:
Citations per year
0 Citations
Abstract:
This work presents a study of the effects of multi-Higgs doublets on the properties of neutrino sector and heavy quark systems. The phenomenological implications of multi-Higgs models, which contain multi-Higgs doublets, in the neutrino and quark sector are discussed in this dissertation. The two-Higgs-doublet model (2HDM), in which t wo Higgs doublets are introduced, is the simplest extension to the scalar sector of th e standard model (SM). A new boson state was recently seen in the CMS (Compact Muon Soleno id) and ATLAS (A Toroidal LHC Apparatus) experiments at the LHC (Large Hadron C ollider). We investigate the multi-Higgs models contributions in understanding various phenomena in the neutrino sector. Introducing a model to explain the neutrino oscillation phenomenon within the framework of multi-Higgs doublets is considered. We introd uce different flavor symmetries in the lepton sector and study the phenomenological co nsequences in both the scalar and lepton sectors. The leptonic mixing in the symmetric limit can be, among other structures, the bi-maximal (BM) or the tri-bimaximal (TBM) mixing. We find that a mixing model with 2-3 flavor symmetry can explain the nonzero θ 13 measurements. In our study, neutrino masses were proposed where its smallness is not due to the seesaw mechanism, i.e. not inversely proportional to some large mass scale. It comes from a one-loop mechanism with dark matter in the loop consisting of singlet Majorana fermions w ithin a model with A 4 flavor symmetry. A relevant point of interest in the neutrino sector is the study of th e nonstandered in- teractions and its implications to neutrino oscillation. Here, we introd uce the nonstandard interaction effects at the detectors of neutrino oscillation experim ents and the impact of extracting the neutrino mixing angles is studied. The extractions of the atmospheric mixing angle θ 23 rely on the standard model cross sections for ν τ + N → τ − + X in ν τ appearance experiments. Corrections to the cross sections from the charge d Higgs and W ′ contribu- tions modify the measured mixing angle. We include form factor effect s in the new physics calculations and find the deviations of the mixing angle. The quark sector has enriched our knowledge of particle physics. L ots of new theories and discovering new attributes of particles have been done in the qu ark sector. Therefore, we study the decay channel of the quarkonium η b → τ + τ − to search for the existance of an additional Higgs field or a new gauge boson. We estimate the standar d model branching ratio for this decay to be ∼ 4 × 10 − 9 . We show that considerably larger branching ratios, up to the present experimental limit of ∼ 8%, is possible in models with a light pseudoscalar or a light axial vector state. Also, in this dissertation we study the forw ard-backward asymmetry A FB in the top quark pair production in the t ̄ t rest frame. In this work we seek for a new gauge boson to accommodating the CDF (Collider Detector at Fermila b) measurement of the A FB , which has a deviation from the next-to leading order (NLO) SM pred iction. A u → t transition via a flavor-changing Z ′ can explain the data. We consider the most general form of the tuZ ′ interaction, which includes vector-axial vector as well as tensor t ype couplings, and study how these couplings affect the top forward-backward a symmetry.- thesis
- new physics
- Z'
- W'
- Higgs particle: doublet
- symmetry: flavor
- flavor: violation
- neutrino: mass
- neutrino: oscillation
- neutrino: mixing angle
References(597)
Figures(0)
- [1]
- [2]
- [3]
- [4]
- [4]
- [4]
- [4]
- [4]
- [5]
- [6]
- [7]
- [8]
- [9]
- [10]
- [11]
- [12]
- [13]
- [14]
- [14]
- [15]
- [15]
- [16]
- [16]
- [16]
- [16]