A first-ever measurement of the Electric Dipole Moment (EDM) of the deuteron at COSY
The most challenging and successful contemporary theory in fundamental research, the Standard Model (SM), has recently completed with the discovery of the Higgs particle. This means that the theory is true. Nevertheless new researches and experiments are going on worldwide in order to discover some phenomena beyond the SM.
One of the ambitious and intriguing directions is a search of the permanent electric dipole moment (EDM) of the elementary particles, namely of charged hadrons. If an EDM would have been found, it would indicate a new source or a cause, which might be responsible for the matter-antimatter asymmetry in the universe. It would also imply the necessity for an extension of the SM towards so-called New Physics. EDM values are extremely small, beyond the state-of-the-art. In spite of the simplicity of the measurement principle - following the time development of the polarization vector of particles subject to a perpendicular electric field - the smallness of the effect provides exceptional challenges, for example to identify and avoid any fake signal.
The new idea, promoted at the Forschungszentrum Jülich (Jülich, Germany) by the JEDI Collaboration, to search for EDMs of charged particles in novel precision storage rings will exploit stored polarized beams and observe a miniscule rotation of the polarization due to the interaction of a finite EDM with large electric fields. The stored beam polarization is measured with the polarimeter consisting of a target and a calorimeter. The new concept of the dedicated polarimetry, proposed by the Georgian group from HEPI TSU in the frame of the collaboration, will enable to push the EDM sensitivity level by orders of magnitude and a possible pioneering EDM discovery.
The results of the project, supported by the SRNSF, namely the development of a crystal calorimeter module, will be used as a polarimeter detector in the measurement of the transverse polarization of the particle beam in the storage ring. The results will help to design, optimize, and starting to build the storage ring internal beam polarimeter. The main features of the polarimeter will be high stability, extremely low uncertainties of measurements, high efficiency and robustness. This polarimeter is a crucial part of the future dedicated ring development for the charged particle EDM measurement.
The HEPI TSU group is a member of the JEDI international collaboration at COSY IKP comprising more than 100 collaborators. The HEPI TSU has accepted the responsibility for design, development, and building of a modern, state-of-the-art polarimeter with excellent performance. The group has more than 20 years of successful experience of collaboration with Nuclear Physics Institute (IKP) of the Forschungszentrum Jülich.