Tanya Zelevinsky Abstract

Tanya Zelevinsky
Harvard University

"Fine Structure Constant Measurement Using Helium Spectroscopy"

The fine structure constant, alpha, is one of the most fundamental constants in physics. Currently, the most precise measurement of alpha comes from the electron g-factor experiments. However, it is vital to determine alpha using other physics, including atomic systems. Helium fine structure happens to be a very suitable system, due to the large splitting and long lifetime of the sublevels. It can yield a precise value of alpha, and can be used to test the internal consistency of QED as well as 3-body QED calculations. The Harvard helium experiment features precision spectroscopy with diode lasers at 1083 nm. Helium-4 atoms are at room temperature in a rf discharge, pressure-regulated vapor cell. The talk will discuss our experimental approach to measuring alpha as well as the results to date and critical systematic effects.