THE FOLLOWING REFERS TO THE PERMANENT ELECTRIC DIPOLE MOMENT
Fundamental particles like electrons and neutrons are predicted by the Standard Model (the current theory of all fundamental particles)
to have permanent electric dipole moments, but they are far too small for existing experiments to measure. Postulated new physics theories, however, predict much larger values of electric dipole moments, which could put them in reach of experiments. Over the next few years the measured limits will be improved by two to three orders of magnitude on the electron and neutron. There are also plans to measure electric dipole moments of atoms, molecules, and nuclei.
An electric dipole moment occurs when the negative charges in a particle are separated from positive charges. Such a separation
violates the combined symmetries of parity and charge conjugation (CP violation). CP violation means that there is difference in the way particles and antiparticles behave. In 1967, Andrei Sakharov pointed out that the only way to explain the fact that most of the universe consists of particles, not antiparticles, is to have particle interactions which do not conserve CP. Since then, a very small level of CP violation has been found in the decay of certain particles (kaons and B-mesons), but it is far too small to explain the asymmetry between matter and antimatter
in the universe. New sources of CP violation are being sought experimentally with high priority being given to experiments aimed at finding new sources of CP violation, for example in searches for electric dipole moments.
Which particle will be the first to be measured to have a non-zero dipole moment, and what will its value be?
What will be its source, the strong, electromagnetic, or weak force?
Fundamental particles like electrons and neutrons are predicted by the Standard Model (the current theory of all fundamental particles)
to have permanent electric dipole moments, but they are far too small for existing experiments to measure. Postulated new physics theories, however, predict much larger values of electric dipole moments, which could put them in reach of experiments. Over the next few years the measured limits will be improved by two to three orders of magnitude on the electron and neutron. There are also plans to measure electric dipole moments of atoms, molecules, and nuclei.
An electric dipole moment occurs when the negative charges in a particle are separated from positive charges. Such a separation
violates the combined symmetries of parity and charge conjugation (CP violation). CP violation means that there is difference in the way particles and antiparticles behave. In 1967, Andrei Sakharov pointed out that the only way to explain the fact that most of the universe consists of particles, not antiparticles, is to have particle interactions which do not conserve CP. Since then, a very small level of CP violation has been found in the decay of certain particles (kaons and B-mesons), but it is far too small to explain the asymmetry between matter and antimatter
in the universe. New sources of CP violation are being sought experimentally with high priority being given to experiments aimed at finding new sources of CP violation, for example in searches for electric dipole moments.
Which particle will be the first to be measured to have a non-zero dipole moment, and what will its value be?
What will be its source, the strong, electromagnetic, or weak force?