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n2EDM: The next measurement of the neutron electric dipole moment

English title n2EDM: The next measurement of the neutron electric dipole moment
Applicant Kirch Klaus
Number 186179
Funding scheme FLARE
Research institution Institut für Teilchen- und Astrophysik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Particle Physics
Start/End 01.04.2019 - 31.03.2021
Approved amount 640'120.00
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Keywords (5)

temperature stabilization; electric dipole moment; ultracold neutrons; neutron; CP violation

Lay Summary (German)

Lead
Permanente elektrische Dipolmomente (EDM) von Systemen mit Spin sind noch nicht entdeckt und verletzten Symmetrien von Zeitumkehr und zwischen Materie und Antimaterie. Viele Experimente suchen nach EDM von Atomen und Teilchen. Die Resultate sind wichtige Tests von Theorien der Teilchenphysik. Das weltweit führende Experiment zur Messung des Neutron-EDM ‘nEDM’ fand am PSI statt. Der Nachfolger ‘n2EDM’ strebt eine mindestens zehnmal empfindlichere Messung an.
Lay summary

Inhalt und Ziel des Forschungsprojekts
Unsere Gruppen von ETH Zürich, Universität Bern und Paul Scherrer Institut (PSI) arbeiten in einer internationalen Kollaboration am PSI und tragen massgeblich zum n2EDM-Aufbau bei. Da das Neutron ein magnetisches Moment besitzt, muss das Magnetfeld extrem genau unter Kontrolle sein. Im Rahmen des FLARE-Projekts erstellen die CH-Gruppen die thermische Stabilisierung von n2EDM, was den Betrieb der von ihnen entwickelten Subsysteme erlaubt. Dazu gehören ein Spulensystem zur aktiven magnetischen Stabilisierung (ETHZ), eine passive magnetische Abschirmung (ETHZ, PSI) und die zentrale Messkammer mit Hochspannung (UBe). FLARE unterstützt die Einbauarbeiten dieser Komponenten. Ein genügend stabiles Feld in der Messkammer benötigt in der inneren passiven Abschirmung über Stunden auf tausendstel Grad stabile Temperaturen.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts
Wir untersuchen eine wichtige Fragestellung moderner Physik, wie die Asymmetrie zwischen Materie und Antimaterie im Universum nach einem symmetrischen Big-Bang entstanden sein kann. Wir entwickeln Methoden zur Stabilisierung und Messung von Magnetfeldern mit Anwendungen über unser Experiment hinaus.


 

 

Direct link to Lay Summary Last update: 01.05.2019

Responsible applicant and co-applicants

Employees

Publications

Publication
Data blinding for the nEDM experiment at PSI
Ayres N. J., Ban G., Bison G., Bodek K., Bondar V., Chanel E., Chiu P.-J., Crawford C. B., Daum M., Emmenegger S., Ferraris-Bouchez L., Flaux P., Grujić Z., Harris P. G., Hild N., Hommet J., Kasprzak M., Kermaïdic Y., Kirch K., Komposch S., Kozela A., Krempel J., Lauss B., Lefort T., et al. (2021), Data blinding for the nEDM experiment at PSI, in The European Physical Journal A, 57(4), 152-152.
A search for neutron to mirror-neutron oscillations using the nEDM apparatus at PSI
Abel C., Ayres N.J., Ban G., Bison G., Bodek K., Bondar V., Chanel E., Chiu P.-J., Crawford C., Daum M., Dinani R.T., Emmenegger S., Flaux P., Ferraris-Bouchez L., Griffith W.C., Grujić Z.D., Hild N., Kirch K., Koch H.-C., Koss P.A., Kozela A., Krempel J., Lauss B., Lefort T., et al. (2021), A search for neutron to mirror-neutron oscillations using the nEDM apparatus at PSI, in Physics Letters B, 812, 135993-135993.
Optically pumped Cs magnetometers enabling a high-sensitivity search for the neutron electric dipole moment
Abel C., Afach S., Ayres N. J., Ban G., Bison G., Bodek K., Bondar V., Chanel E., Chiu P.-J., Crawford C. B., Chowdhuri Z., Daum M., Emmenegger S., Ferraris-Bouchez L., Fertl M., Franke B., Griffith W. C., Grujić Z. D., Hayen L., Hélaine V., Hild N., Kasprzak M., Kermaidic Y., Kirch K., et al. (2020), Optically pumped Cs magnetometers enabling a high-sensitivity search for the neutron electric dipole moment, in Physical Review A, 101(5), 053419-053419.
Search for electric dipole moments
Kirch Klaus, Schmidt-Wellenburg Philipp (2020), Search for electric dipole moments, in EPJ Web of Conferences, 234, 01007-01007.
Measurement of the Permanent Electric Dipole Moment of the Neutron
Abel C., Afach S., Ayres N. J., Baker C. A., Ban G., Bison G., Bodek K., Bondar V., Burghoff M., Chanel E., Chowdhuri Z., Chiu P.-J., Clement B., Crawford C. B., Daum M., Emmenegger S., Ferraris-Bouchez L., Fertl M., Flaux P., Franke B., Fratangelo A., Geltenbort P., Green K., Griffith W. C., et al. (2020), Measurement of the Permanent Electric Dipole Moment of the Neutron, in Physical Review Letters, 124(8), 081803-081803.
Neutron optics of the PSI ultracold-neutron source: characterization and simulation
Bison G., Blau B., Daum M., Göltl L., Henneck R., Kirch K., Lauss B., Ries D., Schmidt-Wellenburg P., Zsigmond G. (2020), Neutron optics of the PSI ultracold-neutron source: characterization and simulation, in The European Physical Journal A, 56(2), 33-33.
Physics beyond colliders at CERN: beyond the Standard Model working group report
Beacham J, Burrage C, Curtin D, De Roeck A, Evans J, Feng J L, Gatto C, Gninenko S, Hartin A, Irastorza I, Jaeckel J, Jungmann K, Kirch K, Kling F, Knapen S, Lamont M, Lanfranchi G, Lazzeroni C, Lindner A, Martinez-Vidal F, Moulson M, Neri N, Papucci M, Pedraza I, et al. (2020), Physics beyond colliders at CERN: beyond the Standard Model working group report, in Journal of Physics G: Nuclear and Particle Physics, 47(1), 010501-010501.
PicoTesla absolute field readings with a hybrid 3He/87Rb magnetometer
Abel Christopher, Bison Georg, Griffith W. Clark, Heil Werner, Kirch Klaus, Koch Hans-Christian, Lauss Bernhard, Mtchedlishvili Alexander, Pototschnig Martin, Schmidt-Wellenburg Philipp, Schnabel Allard, Pais Duarte, Voigt Jens (2019), PicoTesla absolute field readings with a hybrid 3He/87Rb magnetometer, in The European Physical Journal D, 73(7), 150-150.
Magnetic-field uniformity in neutron electric-dipole-moment experiments
Abel C., Ayres N. J., Baker T., Ban G., Bison G., Bodek K., Bondar V., Crawford C. B., Chiu P.-J., Chanel E., Chowdhuri Z., Daum M., Dechenaux B., Emmenegger S., Ferraris-Bouchez L., Flaux P., Geltenbort P., Green K., Griffith W. C., van der Grinten M., Harris P. G., Henneck R., Hild N., Iaydjiev P., et al. (2019), Magnetic-field uniformity in neutron electric-dipole-moment experiments, in Physical Review A, 99(4), 042112-042112.

Collaboration

Group / person Country
Types of collaboration
International nEDM collaboration at PSI, https://www.psi.ch/en/nedm/collaborating-institutions Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Communication with the public

Communication Title Media Place Year
Media relations: print media, online media Magnetically shielded from the rest of the world PSI media release International 2021
Media relations: print media, online media Tracking down the mystery of matter PSI media release; similar releases throughout the nEDM collaborating institutions International 2020

Associated projects

Number Title Start Funding scheme
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
172639 Precision Physics with Muons and Ultracold Neutrons 01.05.2017 Project funding
201473 n2EDM: The next measurement of the neutron electric dipole moment (II) 01.04.2021 FLARE
139140 Passive magnetic shield for the new neutron electric dipole moment experiment n2EDM 01.01.2013 R'EQUIP
200441 Precision Physics with Muons and Ultracold Neutrons II 01.05.2021 Project funding
138211 Measurement of the neutron electric dipole moment 01.11.2011 Project funding
163413 Improving ultracold neutron intensities for frontier precision experiments in fundamental physics 01.11.2015 Project funding
181996 Low Energy Particle Physics with Cold and Ultracold Neutrons 01.08.2019 Project funding
177008 Field Generation and Control System for the n2EDM spectrometer 01.12.2017 R'EQUIP
172626 Highly accurate vector gradiometers for a next-generation neutron EDM experiment 01.08.2017 Project funding
169596 Spin-spectroscopy with ultracold neutrons - Searching for dark matter and lorentz violation using spin-precessing neutrons 01.09.2017 Project funding
178951 A novel neutronics model of the solid D2 ultracold neutron converter at PSI aiming for increasing the source intensity 01.07.2018 Project funding

Abstract

Measurements of permanent electric dipole moments (EDM) of particles with spin are at the forefront of particle physics searches for violations of the combined charge parity symmetry CP. They are considered among the most promising routes to establishing physics beyond the Standard Model of particle physics.The n2EDM experiment is being built and performed by the international nEDM collaboration at PSIusing the high intensity source of ultracold neutrons (UCN) and aiming at an improved measurement of the neutron EDM. The target sensitivity of the n2EDM baseline project is 1E-27ecm and improvements for entering the few 1E-28ecm regime are being developed.With this FLARE grant application the Swiss member groups of the collaboration, from ETHZ, PSI and University of Bern, plan to support their 2019/20 contributions to the setup and the installations. By that, the timely completion of the full hardware of the new n2EDM experiment will be possible.The international nEDM collaboration at PSI has performed the latest world-leading nEDM experiment in the PSI UCN area South. It has accumulated the most sensitive data set in 2015 and 2016 which is currently being analyzed. The result is expected to be published soon.In fall 2017, the nEDM collaboration has disassembled the nEDM apparatus at PSI and started to buildthe new n2EDM experiment in area South. The latter is designed to improve the sensitivity to the permanent neutron EDM by at least an order of magnitude.While our collaboration is leading the field of neutron EDM searches, there is a strong world-wide competition of at least five other sizeable projects on comparable or slightly later schedules, at the ILL Grenoble, at the SNS Oakridge, at LANL Los Alamos, at PNPI Gatchina, and at TRIUMF Vancouver. It is therefore important to keep the momentum high and realize the n2EDM experiment at PSI on time. PSI has laid the foundation for this experiment with the construction of the high intensity UCN source 2005-10 at the second target station of the high intensity proton accelerator (HIPA). ETH Zurich and PSI, supported by SNSF R'equip, matching funds and a major contribution from the former Berthele foundation at ETHZ, have acquired a highly performant, large-volume magnetically shielded room (MSR) which is presently being installed in UCN area South. The UCN source at PSI together with this extraordinary MSR provide the setting for the next world-leading measurement of the neutron electric dipole moment with n2EDM.The Swiss groups contribute to the experiment with major involvement of about 50% of the capital investment and 30% of the scientists. There is SNSF project funding of the involved groups in place. SNSF R'equip is supporting dedicated power supplies for the experiment with matching from PSI. PSI, ETHZ and University of Bern inject additional sizeable funds to the activities of their groups.University of Bern is designing and will be building the most central part, the neutron chambers with specially-coated high-voltage electrodes and high voltage feedthroughs. ETH Zurich is, among other committments, designing and later building the demanding surrounding-field-compensation (SFC) system. While the hardware for these contributions is covered, among others by SNSF project grants and university/ETH money, the design, the integration and later the installation into the full setup need additional technical manpower. It is one part of this grant request to cover 50%-positions for a designer and for a mechanical technician over two years (to be shared between ETHZ and UniBe and frequently working at PSI) in order to help the Zurich and Bern groups to accomplish their tasks. Moreover, the MSR and the whole experiment need a temperature-stabilized environment. The n2EDM setup will therefore be housed in an air-conditioned enclosure (``thermohouse") for which the Swiss groups assumed responsibility. The thermohouse work will be coordinated by PSI as it has to comply with all site-specific standards, especially for safety. It is our aim to fund it commonly from the Swiss institutions via this FLARE grant. The thermohouse is a critical part of the experiment.It will allow stabilizing the temperature around the MSR to less than 1K and, by that, yield a temperature stability of the experiment inside the MSR of a few mK. This is in turn a prerequisite for the magnetic field stability and the operation of the chamber to be built by UniBe. It will also help to keep the experiment clean which is important because of the danger of magnetic contaminants in dust that could enter the experiment. Moreover, the thermohouse provides the supporting structure for the SFC to be built by ETHZ. The coils of the SFC will weigh several tons and need a very solid structure for their mounting. The integration and installation of all these parts should be supported by the requested FLARE technical manpower. The latter will interface with the available technical personnel at PSI working on integration and setup.
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