A team of researchers from the Helmholtz Institute Mainz (HIM) and the Johannes Gutenberg University Mainz (JGU) along with their colleagues from Max Planck Institute for Nuclear Physics, Heidelberg and GSI Helmholtz Center for Heavy Ion Research, Darmstadt, measured the magnetic properties of a single proton. For the first time, they observed spin quantum-jumps of a trapped proton.
The measuring principle used is to observe an individual proton present in an electromagnetic particle trap. Since the same method can be applied to observe an anti-proton, it has become possible to understand the matter-antimatter imbalance.
Like other particles, protons have a natural angular momentum or spinning tendency and a spin quantum jump could be correlated to the flip of a magnetic pole. Although measurement and comparison of magnetic moments of an electron and its anti-particles, the positron, have been achieved in the 1980s, measurements related to a proton was still in progress. The difficulty in detecting a proton spin is that its magnetic moment is 660 times smaller than that of an electron. It took almost five years for the researchers to reach a high precision result in measuring magnetic moments of proton and anti-proton.
The magnetic moment of an anti-proton currently has three decimal points. The Mainz labs aim for an accurate measurement and analysis of matter-antimatter symmetry.
Matter-antimatter symmetry is a key part of the standard model of elementary physics. According to the standard model, particles and anti-particles will act similar when inversions of charge, parity, and time (CPT transformation) are applied at the same time. If the occurrence of this identical behavior is true, it would provide for further theories and studies in physics.