Using electric fields to prevent mirror-trapped antiprotons in antihydrogen studies

The signature of trapped antihydrogen ($\overline{\mathrm{H}}$) atoms is the annihilation signal detected when the magnetic trap that confines the atoms is suddenly switched off. This signal would be difficult to distinguish from the annihilation signal of any trapped $\overline{p}$ that is released when the magnetic trap is switched off. This work deduces the large cyclotron energy ($g$137 eV) required for magnetic trapping of $\overline{p}$, considers the possibility that such $\overline{p}$ are produced, and explores the effectiveness of an electric field applied to clear charged particles from the trapping volume before $\overline{\mathrm{H}}$ detection. No mechanisms are found that can give a $\overline{p}$ such a large cyclotron energy and allow it to mimic an $\overline{\mathrm{H}}$ annihilation. The method used to release $\overline{\mathrm{H}}$ atoms from their magnetic trap without removing the magnetic field gradient that could possibly confine $\overline{p}$ with a high cyclotron energy is also discussed.