Precision Microwave Spectroscopy of the Positronium n=2 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 ¼ 18501.02 AE 0.61 MHz, which is not in agreement with the theoretical value of ν 0 ¼ 18498.25 AE 0.08 MHz.

Observation of asymmetric line shapes in precision microwave spectroscopy of the positronium 2S13→2PJ3

“…The previous Ps fine-structure measurements [17,27,28] are more than 25 years old, and one of the goals of the work presented here was to address the long-standing imbalance between experimental and theoretical uncertainties. Recently we reported a new measurement of the ν 0 interval [18]. Although the uncertainty obtained was a factor of 7 smaller than that of the previous best measurement [17], our measurement exhibited a disagreement with theory [15] amounting to ≈4.2σ .…”

Testing CPT symmetry in ortho-positronium decays with positronium annihilation tomography

“…The most recent measurements of the electron anomalous magnetic moment [11], and its QED predictions based on the recent precise measurement of the fine structure constant [12] agree to 1 part in 10 12 , indicating that no new CPT-violating interactions coupling to the electron could be observed to this level of precision [13]. Nonetheless, the recently discovered deviations from QED predictions in the fine structure of the positronium atom, that is, the bound state of an electron and positron [14], suggest that diverse experimental studies of charged lepton systems should not be hastily abandoned. In fact, as the lightest matter-antimatter bound states, positronium atoms are considered in the context of CPT tests through searches for Lorentz noninvariance.…”

“…Nonetheless, the recently discovered deviations from QED predictions in the fine structure of the positronium atom, that is, the bound state of an electron and positron [14], suggest that diverse experimental studies of charged lepton systems should not be hastily abandoned. In fact, as the lightest matter-antimatter bound states, positronium atoms are considered in the context of CPT tests through searches for Lorentz noninvariance.…”

Models That Link and Suggest Data about Elementary Particles, Dark Matter, and the Cosmos

“…Reference [70] and reference [71] discuss the transition -between two states of positronium -characterized by the expression 2 3 S 1 → 2 3 P 0 . People discuss the energy that associates with the transition.…”