Towards Storage Ring Electric Dipole Moment Measurements

Not only from a particle physicist point of view our existence is still a mystery. According to our current understanding the early universe consisted of the same amount of matter and anti-matter. If the laws of physics obeyed certain symmetries, matter and anti-matter particles should have annihilated. Only due to symmetry breakings in the fundamental interactions, one part, that we call matter today, prevailed.

It turns out that one of the established symmetry breaking mechanisms of the standard model of particle physics, namely the CP-violation, is orders of magnitude too small to explain today’s dominance of matter over antimatter. New CP-violating interaction are thus sought for. These new possible CP-violating effects could manifest themselves in electric dipole moments (EDMs) of fundamental non- selfconjugate particles with spin. A second source of possible CP-violation in the Standard Model is the so-called θ_QCD term. This parameter, which could in principle range from 0 to 2π, is bound to an unnatural small value |θ_QCD| <10⁻¹⁰ by the neutron EDM measurement. This is known in the literature as the strong CP-problem.

In spite of many searches and ever increasing sensitivity, no electric dipole moments have been observed to date. The systems investigated so far include neutrons, muons, atoms and molecules. This workshop focuses on the direct measurement of EDMs of charged hadrons (e.g. proton, deuteron, ³He). Such measurements have never been carried out before. They require the operation of a new kind of high precision storage rings using electric instead of magnetic fields such that simultaneously counter rotating beams will be made possible in order to control and reduce systematic uncertainties.

The aim of the workshop is to bring together experts in experimental, accelerator and theoretical physics to discuss the next steps towards the construction of such a new type of precision storage ring.

The conference language will be English.