# The 24th International Spin Symposium

18-22 October 2021
Matsue, Shimane Prefecture, Japan
Asia/Tokyo timezone

## Electric Dipole Moment Measurements at Storage Rings

18 Oct 2021, 17:35
25m
Matsue, Shimane Prefecture, Japan

#### Matsue, Shimane Prefecture, Japan

Matsue City, Shimane Prefecture, Japan
Plenary Presentation (by invitation only) Plenary presentations

### Speaker

Joerg Pretz (Forschungsyentrum Juelich Germany/RWTH Aachen University)

### Description

Electric Dipole Moments (EDMs) of elementary particles, including hadrons, are
considered as one of the most powerful tool to study CP-violation beyond the Standard Model.
Such CP-violating mechanisms are searched for to
explain the dominance of matter over anti-matter in our universe.

The talk will discuss EDM searches of charged hadrons in storage rings.
Due to an EDM, the spin vector will experience a torque
resulting in a change of the original spin direction which can be
determined with the help of a polarimeter.
Although the principle of the measurement is simple,
the smallness of the expected effect makes this a challenging experiment
requiring new developments in various experimental areas.
Given the complexity of the project, a step wise approach is proposed$^{1)}$.

The talk will discuss activities at the existing storage ring COSY at Forschungszentrum J\"ulich, Germany.
The next step is the design of a 100\,m circumference prototype ring able to demonstrate
key technologies and components. These include simultaneous clockwise and counter-clockwise beam operation
with electrostatic bending elements and, by adding a magnetic field, the frozen spin technique.
The final step is the operation of a pure electric storage ring of about 500\,m circumference.
Other projects like a measurement of the muon EDM will also be discussed.

$^{1)}$ Storage ring to search for electric dipole moments of charged particles, Feasibility study , CPEDM collaboration, https://doi.org/10.23731/CYRM-2021-003

### Primary author

Joerg Pretz (Forschungsyentrum Juelich Germany/RWTH Aachen University)