Infrared and Ultraviolet Physics at Three Energy Scales

This dissertation covers three topics in particle physics phenomenology at three distinct energy scales: first, a discussion of thrust as an event shape variable and how it is useful in studying fragmentation at the GeV scale; second, an exploration into the (lack of) cancellation of electroweak large logarithms at the TeV scale; and third, a calculation of the renormalization group evolution of baryon number violating operators in the standard model effective field theory, relevant at energies well above the electroweak scale. The three topics are introduced as manifestations of infrared and ultraviolet physics in the context of effective field theories.