טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentOmri Bahat-Treidel
SubjectExperimental Probes of the Standard Model
DepartmentDepartment of Physics
Supervisors Mr. Grossman Yuval
Full Professor Rozen Yoram
Full Thesis textFull thesis text - English Version


Abstract

At present, particle physics is described by a gauge invariant, relativistic, local field theory called the Standard Model (SM). Since the 1970's when the full SM has been presented, there has been a great effort to challenge the model's predictions. Though the years, nearly all of these predictions were confirmed within experimental and theoretical uncertainties.

However, there are several unresolved issues which indicate that the SM is not the complete theory of nature. The Higgs boson is yet to be found, and there is no confirmed explanation for the mass of the weak gauge bosons. The baryon asymmetry of the universe calculated according to the SM differs by ten orders of magnitude from the observed value. Observations of solar neutrinos indicate that electron neutrinos disappear. This phenomena can be explained by massive neutrinos which mix with each other. However, massive neutrinos are beyond the scope of the SM. In this work we shall address the first two issues mentioned above.

The spontaneous breaking of  SU(2)*U(1) symmetry is attributed to the Higgs boson. However, the Higgs boson has not been observed yet, and the possibility that it will not be detected by any of the collaborations at the LHC, is quite disturbing. According the SM the neutrino fields are massless and have negative helicity, while experiments indicate that they have small but nonzero mass. The baryon asymmetry of the universe is defined  as the ratio between the baryon number and the entropy of the universe. Within the framework of the SM it has the value eta=10^(-20). Measurements however, show that the value of eta is much larger, and stands on eta_exp=10^(-10).

These open issues are a great motivation to extend the SM. We are going to deal with two different extensions. The first is an extension to the Higgs sector. The second is an extension of the SM with extra singlet right handed neutrino.