ultra cold neutrons; P violation; electric dipole moment; magnetic resonance; Ramsey spectroscopy; CP violation; magnetic fields; 3He magnetometry; T violation; atomic magnetometry; violation of discrete symmetry
Afach S., Ban G., Bison G., Bodek K., Burghoff M., Daum M., Fertl M., Franke B., Grujić Z.D., Hélaine V., Kasprzak M., Kermaïdic Y., Kirch K., Knowles P., Koch H.-C., Komposch S., Kozela A., Krempel J., Lauss B., Lefort T., Lemière Y., Mtchedlishvili A., Naviliat-Cuncic O., Piegsa F.M., Pignol G. (2015), Constraining interactions mediated by axion-like particles with ultracold neutrons, in
Physics Letters B , 745(0), 58-63.
Afach S., Baker Chuck A H, Ban Gilles, Bison Georg, Bodek Kazimierz, Burghoff Martin, Chowdhuri Zema, Daum Manfred, Fertl M., Franke B., Geltenbort Peter V., Green Katie L., Van Der Grinten Maurits G D, Grujić Zoran D., Harris Philip G., Heil Werner, Hélaine V., Henneck Reinhold, Horras M., Iaydjiev P. S., Ivanov Sergey N., Kasprzak Mirosaw M., Kermaïdic Y., Kirch Klaus, Knecht Andreas (2014), A measurement of the neutron to 199Hg magnetic moment ratio, in
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 739, 128-132.
Kraft Andreas, Koch Hans-Christian, Daum Manfred, Heil Werner, Lauer Thorsten, Neumann Daniel, Pazgalev Anatoly, Sobolev Yuri, Weis Antoine (2014), Development of a 3He magnetometer for a neutron electric dipole moment experiment, in
EPJ Techniques and Instrumentation, 1(1), x.
Afach S., Bison G., Bodek K., Burri F., Chowdhuri Z., Daum M., Fertl M., Franke B., Grujic Z., Hélaine V., Henneck R., Kasprzak M., Kirch K., Koch H.-C., Kozela A., Krempel J., Lauss B., Lefort T., Lemière Y., Meier M., Naviliat-Cuncic O., Piegsa F. M., Pignol G., Plonka-Spehr C., Prashanth P. N. (2014), Dynamic stabilization of the magnetic field surrounding the neutron electric dipole moment spectrometer at the Paul Scherrer Institute, in
Journal of Applied Physics, 116(8), 084510.
Grujic Z. D., Weis A (2013), Atomic magnetic resonance induced by amplitude-, frequency-, or polarization-modulated light, in
Phys. Rev. A, 88(1), 012508.
Grujić Zoran D., Koss Peter A., Bison Georg, Weis Antoine, A sensitive and accurate atomic magnetometer based on free spin precession, in
The European Physical Journal D.
We are working in an international collaboration on an experiment aiming at an improved sensitivity to the neutron electric dipole moment (nEDM). The collaboration has existed for several years, and this request is the fourth continuation we are making for our participation in this project.The collaboration will improve the experimental sensitivity to a level below 10^-27 e·cm using ultra cold neutrons (UCN) stored in vacuum. We note that the in-vacuum technique was used by the Sussex-RAL-ILL collaboration to set the present upper limit of d_n to <29×10^-27 e·cm, a value that is claimed to be at its statistical limit [C. A. Baker et al., Phys. Rev. Lett. 97, 131801 (2006)]. The apparatus used in that measure (referred to as "OILL" herein) has been recovered and installed at PSI by the collaboration and will be used in the first phase of the PSI nEDM measurements. A long-term ultimate sensitivity of 10^-28 e·cm is interesting since several extensions to the Standard Model (Left-Right symmetric models, and Supersymmetry) predict a value for the P- and -violating nEDM in that range.Central to this work is the measurement and control of -with particular importance on systematic effects related to- the magnetic field used to precess the magnetic moments of an ensemble of polarized neutrons. The Ramsey method of separated oscillatory fields is used to measure the spin precession of neutrons subjected to a static magnetic field and perturbed by an additional static electric field. The comparison of measurements with parallel fields to those with antiparallel fields isolates any electric field dependence of the precession frequency. The magnetic field stability between two measurements is critical to the sensitivity of the method.The Fribourg atomic physics group (FRAP) works on the task of measuring and stabilizing the magnetic field and its first order gradient to the precision levels necessary for the experiment. Our approach relies on the installation of an array of (several dozen) laser-pumped Cs magnetometer modules inside the vacuum apparatus and use the resulting measurements to both actively stabilize the magnetic field, and to correct the Ramsey oscillating-field phase for rapid magnetic field fluctuations. The magnetometry data collected during the operation of the existing nEDM apparatus will be used to optimize the design of a future nEDM apparatus at the new ultra-cold neutron (UCN) source at PSI. The neutron data collected at the same time should already serve to increase the statistical sensitivity to any nEDM, with the immediate short term goal of d_n