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Measurement of the neutron electric dipole moment

Applicant Kirch Klaus
Number 149211
Funding scheme Project funding
Research institution Institut für Teilchen- und Astrophysik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Particle Physics
Start/End 01.11.2013 - 31.10.2015
Approved amount 360'694.00
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Keywords (3)

magnetic shielding; ultracold neutron; electric dipole moment

Lay Summary (German)

Lead
Die Suche nach permanenten elektrischen Dipolmomenten (EDM) von fundamentalen Teilchen gehört zu den derzeit wichtigsten Experimenten der Niederenergie-Teilchenphysik. Bislang konnten solche EDM noch nicht gefunden werden. In der Standardtheorie der Teilchenphysik sind sie zumeist verschwindend klein. Allerdings hat die Standardtheorie wesentliche Lücken, zum Beispiel bei der Beschreibung der Materie-Antimaterie-Asymmetrie des Universums. Es gibt viele Theorien, die diese Probleme lösen, die allerdings auch beobachtbare EDM vorhersagen. Das EDM des Neutrons (nEDM) gestattet eines der empfindlichsten Experimente und im Rahmen einer internationalen Kollaboration wird an der Quelle für ultrakalte Neutronen am Paul Scherrer Institut danach gesucht.
Lay summary
Unsere Gruppe spielt im nEDM-Experiment am PSI eine wesentliche Rolle. Die Kontrolle des magnetischen Feldes im Experiment muss auf einem Niveau unter 100fT realisiert werden. Zur Stabilisierung des Feldes wird mit verschiedenen Abschirmungen externer Störungen gearbeitet, die sowohl aktiv als auch passiv sein können. Unsere Arbeit konzentriert sich derzeit auf ein das gesamte Experiment umgebendes aktives Kompensationsspulensystem mit vielen Magnetfeldsensoren zur Rückkoppelung. Echtzeitrechnungen der Magnetfeldkorrekturen sollen in Kombination mit vielen Freiheitsgraden des Spulensystems eine Verbesserung der Abschirmung erlauben. Daneben sind wir bei der Datennahme und Auswertung des laufenden nEDM-Experiments aktiv beteiligt.
Direct link to Lay Summary Last update: 06.03.2014

Responsible applicant and co-applicants

Employees

Publications

Publication
A device for simultaneous spin analysis of ultracold neutrons
Afach S., et al. (2015), A device for simultaneous spin analysis of ultracold neutrons, in Eur. Phys. J. A, 51, 143.
Constraining interactions mediated by axion-like particles with ultracold neutrons
Afach S., Ban G., Bison G., Bodek K., Burghoff M., Daum M., Fertl M., Fertl M., Franke B., Grujić Z. D., Hélaine V., Kasprzak M., Kermaïdic Y., Kirch K., Knowles P., Koch H. C. (2015), Constraining interactions mediated by axion-like particles with ultracold neutrons, in Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 745, 58-63.
Gravitational depolarization of ultracold neutrons: comparison with data
Afach S., et al. (2015), Gravitational depolarization of ultracold neutrons: comparison with data, in Phys. Rev. D, 92, 052008.
Highly stable atomic vector magnetometer based on free spin precession
Afach S., Ban G., Bison G., Bodek K., Chowdhuri Z., Grujic Z. D., Hayen L., Helaine V., Kasprzak M., Kirch K., Knowles P., Koch H. -C., Komposch S., Kozela A., Krempel J., Lauss B., Lefort T., Lemiere Y., Mtchedlishvili A., Naviliat-Cuncic O., Piegsa F. M., Prashanth P. N., Quemener G., Rawlik M., Ries D. (2015), Highly stable atomic vector magnetometer based on free spin precession, in OPTICS EXPRESS, 23(17), 22108-22115.
Measurement of a false electric dipole moment signal for 199Hg atoms exposed to an inhomogeneous magnetic field
Afach S., et al. (2015), Measurement of a false electric dipole moment signal for 199Hg atoms exposed to an inhomogeneous magnetic field, in Eur. Phys. J. D, 69, 225.
Observation of gravitationally induced vertical striation of polarized ultracold neutrons by spin-echo spectroscopy
Afach S, et al. (2015), Observation of gravitationally induced vertical striation of polarized ultracold neutrons by spin-echo spectroscopy, in Phys. Rev. Lett. , 115, 162502.
Revised experimental upper limit on the electric dipole moment of the neutron
Pendlebury J.M., et al. (2015), Revised experimental upper limit on the electric dipole moment of the neutron, in Phys. Rev. D, 92, 092003.
A measurement of the neutron to Hg-199 magnetic moment ratio
Afach S., Baker C. A., Ban G., Bison G., Bodek K., Burghoff M., Chowdhuri Z., Daum M., Fertl M., Franke B., Geltenbort P., Green K., van der Grinten M. G. D., Grujic Z., Harris P. G., Heil W., Helaine V., Henneck R., Horras M., Iaydjiev P., Ivanov S. N., Kasprzak M., Kermaidic Y., Kirch K., Knecht A. (2014), A measurement of the neutron to Hg-199 magnetic moment ratio, in PHYSICS LETTERS B, 739, 128-132.
Copper coated carbon fiber reinforced plastics for high and ultra high vacuum applications
Burri F., Fertl M., Feusi P., Henneck R., Kirch K., Lauss B., Ruetimann P., Schmidt-Wellenburg P., Schnabel A., Voigt J., Zenner J., Zsigmond G. (2014), Copper coated carbon fiber reinforced plastics for high and ultra high vacuum applications, in VACUUM, 101, 212-216.
Dynamic stabilization of the magnetic field surrounding the neutron electric dipole moment spectrometer at the Paul Scherrer Institute
Afach S., Bison G., Bodek K., Burri F., Chowdhuri Z., Daum M., Fertl M., Franke B., Grujic Z., Helaine V., Henneck R., Kasprzak M., Kirch K., Koch H. -C., Kozela A., Krempel J., Lauss B., Lefort T., Lemiere 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.
Experimental study of Hg-199 spin anti-relaxation coatings
Chowdhuri Z., Fertl M., Horras M., Kirch K., Krempel J., Lauss B., Mtchedlishvili A., Rebreyend D., Roccia S., Schmidt-Wellenburg P., Zsigmond G. (2014), Experimental study of Hg-199 spin anti-relaxation coatings, in APPLIED PHYSICS B-LASERS AND OPTICS, 115(2), 257-262.
Transmission of ultra-cold neutrons through guides coated with materials of high optical potential
Daum M., Franke B., Geltenbort P., Gutsmiedl E., Ivanov S., Karch J., Kasprzak M., Kirch K., Kraft A., Lauer T., Lauss B., Mueller A. R., Paul S., Schmidt-Wellenburg P., Zechlau T., Zsigmond G. (2014), Transmission of ultra-cold neutrons through guides coated with materials of high optical potential, in NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND, 741, 71-77.

Collaboration

Group / person Country
Types of collaboration
International nEDM collaboration at PSI Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Associated projects

Number Title Start Funding scheme
162574 Measurement of the neutron electric dipole moment 01.11.2015 Project funding
140421 Optical magnetometry for a new neutron EDM experiment 01.04.2012 Project funding
138211 Measurement of the neutron electric dipole moment 01.11.2011 Project funding
144473 Search for the neutron EDM at the high intensity ultracold neutron source at PSI with an upgraded high sensitivity spectrometer - Follow-up application 01.10.2012 Project funding
181996 Low Energy Particle Physics with Cold and Ultracold Neutrons 01.08.2019 Project funding
172626 Highly accurate vector gradiometers for a next-generation neutron EDM experiment 01.08.2017 Project funding
188700 A new search for an electric dipole moment of the neutron with increased sensitivity and an improved UCN source. 01.09.2020 Project funding
150651 A mobile Raman spectrometer to determine the spin population of deuterium gas 01.12.2013 R'EQUIP
139140 Passive magnetic shield for the new neutron electric dipole moment experiment n2EDM 01.01.2013 R'EQUIP
137664 Pushing the high intensity frontier for ultracold neutrons 01.11.2011 Project funding
138211 Measurement of the neutron electric dipole moment 01.11.2011 Project funding

Abstract

The search for electric dipole moments (EDM) of fundamental systems presents a very promising route for finding new physics beyond the Standard Model (SM) of particle physics. A permanent electric dipole moment violates parity and time reversal symmetries and, invoking the CPT theorem, also CP symmetry. New sources of CP violation are expected to be found in order to understand the observed large baryon asymmetry of our universe (BAU) and because most extensions of the SM allow for new CP violating phases. Various non-observations of finite EDM, of the neutron as well as of nuclei, e.g. with the Hg-199 atom, and the electron, e.g. via the YbF molecule, so far present the most stringent constraints on new physics models of CP violation involving particles of the first generation. Many efforts world wide are underway to search for EDM in various systems like atoms, molecules, muons, light nuclei and neutrons.In this proposal we ask for a substantial support of the ETH group in the neutron EDM (nEDM, d_n) search at PSI. The ETH group is playing an important role, both in the operation and analysis of the ongoing nEDM experiment and in the design and construction of the new n2EDM apparatus. In the past 18 months, we concentrated our activities first on contributing to the operation and improvement of operation of nEDM, with a leading role in DAQ software development and work on the active surrounding field compensation. We also contributed to the preparation of the setup area for n2EDM with passive shielding for higher frequency (e.g. RF) noise and lab studies of the n2EDM active surrounding field compensation system. On the present SNF grant 138211, our PhD student G. Wyszynski (GW) joined the team in November 2011, our Postdoc J. Krempel (JK) joined in February 2012 coming from the PSI nEDM team and bringing with him very important specific know-how on measurement techniques, data acquisition and analysis. He is, in the meantime, playing a key role in almost all DAQ aspects of the nEDM experiment. Here, we ask for the extension of the SNF grant and the positions of the doctoral student and the postdoc for 24 months which will be essential for the successful continuation of the work started. It covers the first run period of the nEDM experiment during 2013-14 and subsequent analysis of the data. We expect to within this running period exceed the sensitivity of the best nEDM search to date.In addition, we propose to grant a second PhD student position which would allow studying in more detail issues with the passive mu-metal magnetic shield for n2EDM to which we are contributing with very substantial financial means. Our initial grant application two years ago included the request for a doctoral student and a postdoc in connection with this topic. While this couldn't be granted at that time, it is important to enter the respective studies now in order not to delay the n2EDM setup. This SNF application is the second for the ETHZ group in this project which is planned as a long term activity of the group.
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