Precision Microwave Spectroscopy of the Positronium <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>2</mml:mn></mml:math> Fine Structure

Abstract

We report a new measurement of the positronium (Ps) 2^{3}S_{1}→2^{3}P_{0} interval. Slow Ps atoms, optically excited to the radiatively metastable 2^{3}S_{1} level, flew through a microwave radiation field tuned to drive the transition to the short-lived 2^{3}P_{0} level, which was detected via the time spectrum of subsequent ground state Ps annihilation radiation. After accounting for Zeeman shifts we obtain a transition frequency ν_{0}=18501.02±0.61 MHz, which is not in agreement with the theoretical value of ν_{0}=18498.25±0.08 MHz.

Topics & Concepts