Abstract
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 ($>$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.
Highlights
Antihydrogen atoms have recently been trapped for up to about 1000 s by both the ATRAP and ALPHA Collaborations at CERN [1,2]
It is important that the signal used to identify and count an H atom is from a trapped atom and not from a trapped pthat is released at the same time, given that an H and a phave the same annihilation signals
The signals that establish that an average of five H atoms per trial have been confined in a quadrupole Ioffe trap for 15 to 1000 s seem to be properly attributed to H atoms rather than to mirror-trapped pthat are released at the same time
Summary
Antihydrogen atoms have recently been trapped for up to about 1000 s by both the ATRAP and ALPHA Collaborations at CERN [1,2]. ATRAP observed an average of 5 atoms per trial confined for 15 s, while ALPHA trapped approximately 0.7 H atoms per trial for 10 s using smaller numbers of antiprotons (p) and positrons (e+). These are important steps towards the proposed use of trapped H atoms [3] for CPT tests with precision spectroscopy [4] and for proposed gravitational studies with trapped antimatter atoms [5], though larger numbers of trapped atoms will be required. The H atoms are released for detection while the mirror trap from the axially symmetric Ioffe field coils is left on. Mirror trapping requires considerably more pcyclotron energy in our apparatus compared to another that has been studied [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
