#### Title

Precision low energy measurements and search for physics beyond the standard model

#### Date of Completion

January 2002

#### Keywords

Physics, Elementary Particles and High Energy

#### Degree

Ph.D.

#### Abstract

In the first two parts of this dissertation I present the complete calculation of one-loop contributions to low energy charged and neutral current weak interaction observables in the framework of the Minimal Supersymmetric Standard Model (MSSM). For the former, I perform the first *model-independent * analysis of charged current data and use it to constrain the MSSM parameter space. I show that the constraints are incompatible with the predictions of the most widely used models of SUSY breaking mediation and discuss possible solutions to this conflict. For neutral current reactions, I study the impact of SUSY corrections on the weak charges of the electron, Q^{e}W , and the proton, Q^{p}W . I show that the relative signs of the SUSY loop effects on Q^{e}W and Q^{p}W are *correlated and positive*, whereas inclusion of R-parity nonconserving interactions can lead to *opposite* sign relative shifts. Thus, a comparison of Q^{p}W and Q^{e}W measurements could help distinguish between different SUSY scenarios. ^ In the third part, I construct the relationship between effective, nonrenormalizable, time-reversal violating (TV) parity-conserving (PC) interactions of quarks and gauge bosons and various low-energy TVPC and TV parity-violating (PV) observables. I delineate the scenarios under which experimental limits on electric dipole moments (EDM's) of the electron, neutron, and ^{199}Hg as well as limits on TVPC observables provide the most stringent bounds on new TVPC interactions. If parity invariance is restored at short distances, the one-loop EDM of elementary fermions generate the most severe constraints. If parity remains broken at short distances, direct TVPC limits provide the least ambiguous bounds. ^ In the fourth part I evaluate the one-loop SM radiative corrections to the charged (CC) and neutral (NC) current neutrino-deuterium disintegration cross sections for energies relevant to the Sudbury Neutrino Observatory (SNO) experiment. The correction to the *total* CC cross section is independent of the bremsstrahlung detection threshold. It slowly decreases with neutrino energy *E*_{ν} from about 4% at low energies to 3% at the end of the ^{8}B spectrum. The correction to the NC cross section amounts to about 1.5% and is energy-independent. ^

#### Recommended Citation

Kurylov, Andriy Alexandrovich, "Precision low energy measurements and search for physics beyond the standard model" (2002). *Doctoral Dissertations*. AAI3066249.

https://digitalcommons.lib.uconn.edu/dissertations/AAI3066249