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Präzisionsexperimente - Abteilung Blaum
Abstract:
Invariance under the charge, parity, time-reversal (CPT) transformation
is one of the fundamental symmetries of the standard
model of particle physics. This CPT invariance implies that the
fundamental properties of antiparticles and their matter-conjugates
are identical, apart from signs. There is a deep link between CPT
invariance and Lorentz symmetry—that is, the laws of nature seem
to be invariant under the symmetry transformation of spacetime—
although it is model dependent. A number of high-precision CPT
and Lorentz invariance tests—using a co-magnetometer, a torsion
pendulum and a maser, among others—have been performed, but
only a few direct high-precision CPT tests that compare the fundamental
properties of matter and antimatter are available. Here
we report high-precision cyclotron frequency comparisons of a single
antiproton and a negatively charged hydrogen ion (H-) carried
out in a Penning trap system. From13,000 frequencymeasurements
we compare the charge-to-mass ratio for the antiproton (q/m)p-
to that for the proton (q/m)p and obtain (q/m)p-/(q/m)p--1=1(69) x 10-12. The measurements were performed at cyclotron frequencies
of 29.6 megahertz, so our result shows that the CPT theorem
holds at the atto-electronvolt scale. Our precision of 69 parts
per trillion exceeds the energy resolution of previous antiproton-toproton
mass comparisons7,9 as well as the respective figure of merit
of the standardmodel extension10 by a factor of four. In addition,we
give a limit on sidereal variations in the measured ratio of <720
parts per trillion.By following the arguments of ref. 11, our result can
be interpreted as a stringent test of the weak equivalence principle of
general relativity using baryonic antimatter, and it sets a new limit on
the gravitational anomaly parameter of |ag-1|<8.7 x 10-7.
