New high-precision comparison of electron and positron<i>g</i>factors

TLDR

Single electrons and positrons have been alternately isolated in the same compensated Penning trap to form the geonium pseudoatom under nearly identical conditions. For each particle, the g‑factor anomaly is obtained by measuring both the spin‑cyclotron difference frequency and the cyclotron frequency. A systematic search revealed a small residual shift from the cyclotron excitation field, and extrapolation to zero power produced e⁺ and e⁻ g factors with reduced statistical error, yielding a particle–antiparticle comparison of g(e⁻)/g(e⁺)=1+(0.5±2.1)×10⁻¹². The other information provided is .

Abstract

Single electrons and positrons have been alternately isolated in the same compensated Penning trap in order to form the geonium pseudoatom under nearly identical conditions. For each, the g-factor anomaly is obtained by measurement of both the spin-cyclotron difference frequency and the cyclotron frequency. A search for systematic effects uncovered a small (but common) residual shift due to the cyclotron excitation field. Extrapolation to zero power yields ${e}^{+}$ and ${e}^{\mathrm{\ensuremath{-}}}$ g factors with a smaller statistical error and a new particle-antiparticle comparison: g(${e}^{\mathrm{\ensuremath{-}}}$)/ g(${e}^{+}$)=1+(0.5\ifmmode\pm\else\textpm\fi{}2.1)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}12}$. . AE