Probing New Physics Through Third Generation Leptons

This dissertation is a study of beyond standard model physics or new physics. The third generation charged lepton -the τ -is an excellent probe of new physics (NP) because of it being the heaviest lepton. As the heaviest lepton, it has the largest coupling ( among the leptons) to the Higgs boson in the Standard Model (SM). New physics contributions to the tau-neutrino nucleon scattering were considered. Charged Higgs and W' effects to the deep inelastic scattering ντ ( [special character omitted]τ) + N → τ− (τ+) + X in the neutrino-nucleon interactions has been studied. The neutrino detection process at neutrino oscillation experiments modify the measured atmospheric and reactor mixing angles &thetas;23 and &thetas; 13, respectively. A significant deviation from the standard model was observed in terms of the neutrino mixing angles. The semileptonic decays of B meson to the τ lepton is mediated by a W boson in the SM. In many models of NP this decay gets contributions from additional states like new vector bosons, leptoquarks or new scalar particles. These new states affect the semileptonic b → c and b → u transitions and gave rise to new physics beyond the standard model. We have presented the angular B¯ → D*+ τ − [special character omitted]τ with the most general new physics structure including tensor op- distribution for B erators. We have then discussed the effects of the tensor operators on various observables that can be constructed out of the angular distribution. Our focus was on the azimuthal observables which include the important CP violating triple product asymmetries. We found that these azimuthal asymmetries, have different sensitivities to different new physics structures and hence they are powerful probes of the nature of the NP.

Name thesis:degree_name

Ph.D. in Physics

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics and Astronomy

Year dc:date.available

2014

Author dc:creator

• Sharma, Preet

Contributors dc:contributor

• Alakabha Datta
• Micah B. Milinovich
• Luca Bombelli

• Elementary Particles and Fields and String Theory

Repository record dc:identifier

https://egrove.olemiss.edu/etd/774

OAI identifier oai:identifier

oai:egrove.olemiss.edu:etd-1773