Doctor of Philosophy (Ph.D.)
Carl E Carlson
The Standard Model describes a wide range of fundamental interactions. Searches are ongoing for experimental results that differ from the Standard Model predictions. Such disagreements would both indicate that the Standard Model is incomplete and constrain the properties of New Physics scenarios. to probe the Standard Model over a wide kinematic range, low energy tests are necessary to complement experiments in the high energy regime. We perform calculations for experiments that are representative of two general types of low energy tests. The Qweak experiment at Jefferson Lab is a low energy measurement of the weak charge of the proton. Since the weak charge is proportional to the weak mixing angle, the result can be interpreted as a test of the Standard Model prediction that coupling parameters "run" as the energy of the interaction changes. to determine whether New Physics is present in the Qweak measurement, all Standard Model physics must be correctly accounted for. We present our calculation of a particularly troublesome radiative correction, the gammaZ box. We focus particularly on our models of the unmeasured structure functions FgZ1,2,3 (x, Q2) and discuss how they can be experimentally determined in the future. Atomic systems can also be used to test the Standard Model at low energies. Recently, there has been a discrepancy between the proton's charge radius extracted from electronic and muonic hydrogen measurements. This discrepancy could be a sign of New Physics for the muon and we present our model that bring the two radii extractions into agreement.
© The Author
Rislow, Benjamin Carl, "Low Energy Tests of the Standard Model" (2013). Dissertations, Theses, and Masters Projects. Paper 1539623625.