Summary of Physics doctoral thesis: Some new physics effects in the 3 − 2 − 3 − 1 and 3 − 4 − 1 models

Investigate the scalar section, the gauge section, and currents in the 3 − 2 − 3 − 1 model and the minimal 3 − 4 − 1 model with right-handed neutrino. Identifying particles and interactions of SM as well as predicting new particles and interactions.
Nội dung trích xuất từ tài liệu:
Summary of Physics doctoral thesis: Some new physics effects in the 3 − 2 − 3 − 1 and 3 − 4 − 1 models MINISTRY OF EDUCATION AND VIETNAM ACADEMY TRAINING OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY ----------------- DUONG VAN LOI SOME NEW PHYSICS EFFECTS IN THE 3 − 2 − 3 − 1 AND 3 − 4 − 1 MODELS Major: Theoretical and Mathematical Physics Code: 62 44 01 03 SUMMARY OF PHYSICS DOCTORAL THESIS HANOI - 2018 The work has been completed at Graduate University of Science and Technology, Vietnam Academy of Science and Technology Scientific Supervisor: Prof.Dr. Hoang Ngoc Long - Institute of Physics, Graduate University of Science and Technology Referee 1: Prof.Dr. Dang Van Soa - Hanoi Metropolitan University Referee 2: Assoc.Prof.Dr. Phan Hong Lien - Military Technical Academy Referee 3: Dr. Nguyen Huy Thao - Hanoi Pedagogical University 2 This dissertation will be defended in front of the evaluating assembly at academy level, Place of defending: meeting room, Graduate University Science and Technology, Vietnam Academy of Science and Technology. The thesis can be found at - National Library; - Institute of Physics Library. INTRODUCTION 1. Motivation of thesis topic The Standard Model (SM) is a very good theory for describing three basic types of interactions and this has been empirically tested. However, SM has yet to explain some issues such as the generation number equal to three, the small mass of the neutrino, the existence of dark matter. At the same time, some results in SM related to the ρ-parameter, the neutral meson mass differences, the total decay width of the W boson, ... do not coincide with the experiment, although the difference is very small. Many other characteristics also indicate that SM is an effective theory of a more fundamental theory. Therefore, the development of extended theories to solve existing problems is very natural and necessary. In SM extensions, expanding the gauge symmetry group of the electroweak part is very much in the interest of many scientists. Accordingly, the model based on the SU (3)C ⊗ SU (2)L ⊗ SU (3)R ⊗ U (1)X (3 − 2 − 3 − 1) gauge group has just been proposal. The 3 − 2 − 3 − 1 model can address issues beyond the scope of SM mentioned above. This new gauge symmetry yields that the fermion generation number is 3, and the tree-level flavor-changing neutral currents (FCNCs) arise in both gauge and scalar sectors, which may be the new source for addressing the physics anomalies and others. Also, it can provide the observed neutrino masses, as well as dark matter candidates, automatically. In addition, the extension model based on the SU (3)C ⊗ SU (4)L ⊗ U (1)X (3 − 4 − 1) gauge group is also a natural and logical extension. The 3 − 4 − 1 model can have two scales of breaking at high energies that make it easy to meet the requirements of the experiment. Furthermore, in some 3 − 4 − 1 specific models, the lepton multiplets contain all of the lepton (left-handed, right-handed) of SM and right-handed neutrinos - important components to solve the neutrino mass problem. This is a reasonable arrangement and only 1 available in the 3 − 4 − 1 models. However, the Higgs physics - currently the most important sector - has not received enough attention. For the reasons above, we chose the subject Some new physics effects in the 3 − 2 − 3 − 1 and 3 − 4 − 1 models. 2. The objectives of the thesis • Investigate the scalar section, the gauge section, and currents in the 3 − 2 − 3 − 1 model and the minimal 3 − 4 − 1 model with right-handed neutrino. Identifying particles and interactions of SM as well as predict- ing new particles and interactions. • Solve the problem of the fermion generation number, neutrino mass. The identification of dark matter candidates in the 3 − 2 − 3 − 1 model. • Investigate some new physics effects and find the constraints for a few parameters in the two models. 3. The main contents of the thesis • Overview of SM and some of SM’s expansions. • Investigating the 3 − 2 − 3 − 1 model with arbitrary electric charges of the new leptons. Find the spectrum of the gauge and scalar, defining the currents. Discussing the problem of the fermion generation number, neutrino mass, and determine dark matter candidates in the model. In- vestigating some new physics effects related to ρ-parameter and FCNCs. • Investigating the 3 − 4 − 1 model with arbitrary electric charges of the new leptons. Considering the conditions for anomaly free, Yukawa in- teractions and fermion mass, and the boson gauge mass. Investigating the minimal 3 − 4 − 1 model with right-handed neutrino. Detailed anal- ysis of the gauge boson, the currents, and more importantly the Higgs. Considering the decay channels of W boson and muon. 2 CHAPTER 1. OVERVIEW 1.1. The Standard Model The gauge symmetry of the model is defined by SU (3)C ⊗ SU (2)L ⊗ U (1)Y (3-2-1), where the last two are the electroweak symmetry. The electric charge operator: Q = T3 + Y /2. The fermion content: ! νiL ψiL = ∼ (1, 2, −1) , eiR ∼ (1, 1, −2), i = 1, 2, 3. eiL !       uiL 1 4 2 QiL = ∼ 3, 2, , uiR ∼ 3, 1, , diR ∼ 3, 1, − . (1.1) diL 3 3 3 To break the gauge symmetry, the scalar multiplets are introduced as ...