Collective oscillations of a stored deuteron beam close to the quantum limit

We investigated coherent betatron oscillations of a deuteron beam in the storage ring COSY, excited by a detuned radio-frequency Wien filter. These beam oscillations were detected by conventional beam position monitors, read out with lock-in amplifiers. The response of the stored beam to the detuned Wien filter was modelled using the ring lattice and time-dependent 3D field maps of the radio-frequency Wien filter. The influence of uncertain system parameters related to manufacturing tolerances and electronics was investigated using the polynomial chaos expansion. With the currently available apparatus, we show that oscillation amplitudes down to \SI{1}{\micro \meter} can be detected. Future measurements of the electric dipole moment of protons will, however, require control of the relative position of counter-propagating beams in the sub-picometer range. Since the stored beam can be considered as a rarefied gas of uncorrelated particles, we moreover demonstrate that the amplitudes of the zero-point betatron oscillations of individual particles are within a factor of 10 of the Heisenberg uncertainty limit. As a consequence of this, we conclude that quantum mechanics does not preclude the control of the beam centroids to sub-picometer accuracy. The smallest Lorentz force exerted on a single particle that we have been able to determine is \SI{10}{aN}.Comment: 38 pages, 16 figure

First Search for Axion-Like Particles in a Storage Ring Using a Polarized Deuteron Beam

Based on the notion that the local dark-matter field of axions or axion-like particles (ALPs) in our Galaxy induces oscillating couplings to the spins of nucleons and nuclei (via the electric dipole moment of the latter and/or the paramagnetic axion-wind effect), we performed the first experiment to search for ALPs using a storage ring. For that purpose, we used an in-plane polarized deuteron beam stored at the Cooler Synchrotron COSY, scanning momenta near 970 MeV/c. This entailed a scan of the spin precession frequency. At resonance between the spin precession frequency of deuterons and the ALP-induced EDM oscillation frequency there will be an accumulation of the polarization component out of the ring plane. Since the axion frequency is unknown, the momentum of the beam and consequently the spin precession frequency were ramped to search for a vertical polarization change that would occur when the resonance is crossed. At COSY, four beam bunches with different polarization directions were used to make sure that no resonance was missed because of the unknown relative phase between the polarization precession and the axion/ALP field. A frequency window of 1.5-kHz width around the spin precession frequency of 121 kHz was scanned. We describe the experimental procedure and a test of the methodology with the help of a radiofrequency Wien filter located on the COSY ring. No ALP resonance was observed. As a consequence an upper limit of the oscillating EDM component of the deuteron as well as its axion coupling constants are provided.Comment: 25 pages, 24 figures, 7 tables, 67 reference

Electric dipole moments of charged particles at storage rings

The Standard Model (SM) of Particle Physics cannot explain the matter-antimatter asymmetry in the Universe. Therefore, the search of physics beyond the SM is required and one way to achieve it is to strive for the highest precision in the search for electric dipole moments (EDMs). Permanent EDMs of particles violate both time reversal and parity invariance and, via the CPT theorem, also the combined CP symmetry. Finding an EDM would be a strong indicator for physics beyond the SM.Storage rings offer possibility to measure EDMs of charged particles by observing the influence of the EDM on the spin motion in the ring. The Cooler Synchrotron COSY at the Forschungszentrum Juelich provides polarized protons and deuterons with momenta up to 3.7 GeV/s, making it an ideal testing ground and starting point for the JEDI collaboration (Juelich Electric Dipole moment Investigations) for such an experimental program. The talk will present the JEDI program for the measurement of proton and deuteron EDMs and discuss recent results of the first direct (precursor) measurements of the deuteron EDM in COSY

The search for electric dipole moments of charged particles using storage rings

One of the major problems of modern particle physics is the inability of the Standard Model (SM) of Particle Physics to explain the matter-antimatter asymmetry in the Universe. Therefore, the pursuit of physics beyond the SM is required and one of the necessary conditions for the appearance of the matter-antimatter asymmetry is the violation of the CP symmetry. Permanent electric dipole moments (EDMs) of particles violate CP symmetry, so EDM measurements of fundamental particles are able to probe new sources of CP-violation.Storage rings make it possible to measure EDMs of charged particles by observing the effect of the EDM on the spin motion in the ring. The Cooler Synchrotron COSY at the Forschungszentrum Julich provides polarized protons and deuterons with momenta up to 3.7 GeV/s, which is an ideal testing ground and starting point for the JEDI collaboration (Jülich Electric Dipole moment Investigations) for such an experimental program.The preliminary results of the first direct (precursor) measurements of the deuteron EDM in COSY are presented. This is the first stage of the experimental program to determine the EDMs of proton and deuteron using storage ring

The search for electric dipole moment of charged particles using storage rings

The Standard Model (SM) of Particle Physics cannot explain the matter-antimatter asymmetry in the Universe, which is why physics beyond the SM must be pursued. The search for permanent Electric Dipole Moments (EDMs) of elementary particles can be a powerful tool to probe new sources of CP-violation. Finding an EDM would be a convincing indicator for physics beyond the SM. Storage rings make it possible to measure EDMs of charged particles by observing the effect of the EDM on the spin motion in the ring. The Cooler Synchrotron COSY at the Forschungszentrum Juelich provides polarized protons and deuterons with momenta up to 3.7 GeV/s, which is an ideal testing ground and starting point for such an experimental program. The analysis of the first direct (precursor) measurement of the deuteron EDM in COSY is currently ongoing. Due to the complexity of storage rings, this study requires precision in measurements and thorough understanding of systematics. Beyond that, the design report of the prototype EDM storage ring is the next milestone of the JEDI (Juelich Electric Dipole moment Investigations) research program. In this talk, I will present the current status of the JEDI program for the measurement of proton and deuteron EDMs, discuss the various technical developments, and show recent results

Progress toward the first measurement of the deuteron Electric Dipole Moment at COSY

One of the major problems of modern particle physics is the inability of the Standard Model (SM) to explain the matter-antimatter asymmetry of the Universe. Permanent electric dipole moments (EDMs) of particles violate both time reversal (T) and parity (P) invariance, and are via the CPT-theorem also CP-violating. Therefore, measurements of EDMs of fundamental particles probe new sources of CP-violation, and finding an EDM would be a strong indication for physics beyond the SM.Up to now, EDM searches mostly focused on neutral systems (neutrons, atoms, and molecules). Storage rings, however, offer the possibility to measure EDMs of charged particles by observing the influence of the EDM on the spin motion in the ring. Direct searches of proton and deuteron EDMs using a storage ring thus bear the potential to reach sensitivities beyond $10^{−29}$ e·cm. In this talk I will discuss recent results of a “percursor” deuteron EDM experiment, presently being carried out at the Cooler Synchrotron COSY at Forschungszentrum Jülich