Breakfast Journal Club

An experimental limit on the charge of antihydrogen - ALPHA collaboration

by Dr. Martin Simon (Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria)

Wednesday, 8 October 2014 from to (Europe/Vienna)
at SMI ( Lunch room (1.08) )
Boltzmanngasse 3 1090 Wien
Description The properties of antihydrogen are expected to be identical to those of hydrogen, and any differences would constitute a profound challenge to the fundamental theories of physics. The most commonly discussed antiatom-based tests of these theories are searches for anti-hydrogen-hydrogen spectral differences (tests of CPT (charge-parity-time) invariance) orgravitational differences (tests of the weak equivalence principle). Here we, the ALPHA Collaboration, report a different and somewhat unusual test of CPT and of quantum anomaly cancellation. A retrospective analysis of the influence of electric fields on antihydrogen atoms released from the ALPHA trap finds a mean axial deflection of 4.1±3.4 mm for an average axial electric field of 0.51 Vmm-1. Combined with extensive numerical modelling, this measurement leads to a bound on the charge Qe of antihydrogen of Q = (-1.3 ± 1.1 ± 0.4) x 10-8. Here, e is the unit charge, and the errors are from statistics and systematic effects.

Amole, C. et al. An experimental limit on the charge of antihydrogen. Nat. Commun. 5:3955 doi: 10.1038/ncomms4955 (2014).