Developments for the direct determination of the g-factor of a single proton in a Penning trap

Abstract

The measurement and comparison of the magnetic moment (or g-factor) of the proton and antiproton provide a stringent experimental test of the CPTtheorem in the baryonic sector (Quint et al., Nucl Instrum Methods Phys Res, B 214:207, 2004). We present an experimental setup for the first direct high-precision measurement of the g-factor of a single isolated proton in a double cylindrical Penning trap. The application of the continuous Stern-Gerlach effect to detect quantum jumps between the two spin states of the particle, together with a novel trap design specially developed for this purpose, offers the possibility of measuring the magnetic moment not only of a single proton but also of a single antiproton. It is aimed to achieve a relative uncertainty of 10 −9 or better. Preliminary results including mass spectra of particle clouds as well as single proton preparation and detection are shown.

Observation of Spin Flips with a Single Trapped Proton

“…The precision achieved by that experiment is 1 part in 10 8 , limited by the "wall shift" due to the interaction of the hydrogen atoms with the maser cavity. Our experiment aims at a direct measurement of the magnetic moment of one individual proton stored in a Penning trap [3,4]. The particle is confined to a volume below 100 µm 3 by means of electrostatic and magnetostatic fields.…”

Antimatter-gravity couplings, and Lorentz symmetry

“…The comparison of energy levels for trapped particles with those of trapped antiparticles also leads to CPT-violation sensitivities in the SME [10]. This method has led to experimental results for coefficients for Lorentz violation associated with the electron [20] and proton [21] and ongoing experiments provide the possibility of further results [22].…”

Trapped Ion Oscillation Frequencies as Sensors for Spectroscopy

“…Also, they have provided the so far most precise value of the electron’s atomic mass [ 29 ]. Currently ongoing effort are directed towards similar measurements in medium-heavy and heavy, hydrogen- and lithium-like ions [ 30 , 31 ] as well as in free protons and antiprotons [ 30 , 32 , 33 ] with the goal of reaching even more stringent tests of theory contributions and possible determinations of fundamental constants [ 28 ].…”