SPP 1491:  Precision Experiments in Particle- and Astrophysics with Cold and Ultracold Neutrons

• Subject Area: Physics
• Term: from 2010 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 130699104

This Priority Programme wants to address some of the unsolved questions of modern science: the nature of the fundamental forces and underlying symmetries, as well as the nature of the gravitational force at very small distances. New facilities and technological developments now open the window for significant improvement in precision by one to two orders of magnitude over previous investigations. This allows to probe these questions in a complementary way to LHC-based experiments or even outline a unique way. The research programme will focus on four Priority Areas, which are directly related to specific physics/astrophysics issues: Priority Area A: CP-symmetry violation and particle physics in the early universe (addressed mainly by the search for the neutron electric dipole moment); Priority Area B: the structure and nature of weak interaction and possible extensions of the standard model (addressed mainly by precise studies of the neutron beta decay); Priority Area C: relation between gravitation and quantum theory (probed by investigations of low-energy bound states in the gravitational field); Priority Area D: charge quantisation and the electric neutrality of the neutron (probed by a precision test of the neutron’s electric charge).The intended improvement in experimental precision has to go in parallel with the development of new or improved measurement techniques, which are often at the extreme border of feasibility.
Novel powerful sources for ultracold neutrons are presently being prepared at various research centres. They will allow us to perform high-precision experiments on gravitation and the electric dipole moment of the neutron. On the other hand, neutron beta decay studies require a very brilliant “source” of decay products, i.e., a large “active decay volume” inside a cold neutron guide. These measurements should enable us to probe new physics almost independent of the mass scale (EDM) and to understand CP-symmetry violation in processes relevant to the matter-antimatter asymmetry of the universe.
The structure of weak interaction can be tested with unprecedented precision, making possible to be sensitive to new intermediate bosons without direct observation. Thus, the origin of nature’s left-handedness observed today may be revealed. Precision studies of Newton’s law at very small distances in turn allow to probe for extra dimensions at the µm level and can reveal the existence of new gauge bosons acting within. This again could hint to the space-time structure at very early times of the universe and is related to the curling up of extra space dimensions in the inflationary phase of the universe.

• DFG Programme: Priority Programmes
• International Connection: Austria, France, Switzerland

Projects

• Advanced control and manipulation of neutron beam intensity and polarisation in precsion neutron experiments (Applicant Jericha, Erwin )
• Calibration sources for proton spectroscopy in neutron decay (Applicant Soldner, Torsten )
• CASCADE, neutron detectors for highest count rates of cold and ultra-cold neutrons in combination with fast self-triggering readout electronics (Applicant Klein, Martin )
• Construction of a neutron guiding component (further called 'neutron switch') for an experiment to measure the electric dipole moment of the neutron at the Paul Scherrrer Institut (PSI) in Villigen, Switzerland (Applicant Plonka-Spehr, Christian )
• Construction of a storage device for ultra-cold neutrons (UCN) using superconducting magnets for measuring the lifetime of the free neutron with the experiment PENeLOPE (Applicant Paul, Stephan )
• Defining polarised neutron beams in high-precision experiments with PERC (Applicant Jericha, Erwin )
• Development of a high-resolution optical magnetic-field sensor for experiments to measure the electric dipole moment of the neutron (Applicant Bison, Georg )
• Development of a miniaturized SQUID measuring systems for an experiment to measure the electric dipole moment of the neutron (Applicant Fierlinger, Peter )
• Development of a procedure to optimize magnetic shielding for spin precession experiments like nEDM (Applicant Burghoff, Martin )
• Development of a prototype shield for a new EDM experiment (Applicant Paul, Stephan )
• Development of new, non-depolarizating and high reflective coatings based on B-C-N compounds for application in fundamental neutron physics (Applicants Bräuer, Günter ;  Lauer, Thorsten )
• Development of simulation, data acquisition and analysis systems for the next-generation measurement of the neutron EDM (Applicant Marino, Michael )
• Ein nichtdepolarisierender Neutronenleiter für PERC (Applicant Schmidt, Ulrich )
• Electron spectroscopy with PERC (Applicant Abele, Hartmut )
• Entwicklung eines Mehrkammer-(Ko)Magnetometers mit 199Hg für eine neue Messung des Neutron EDM (Applicant Petzoldt, Gerd )
• Entwicklung externer und interner Magnetfelder für ein EDM Experiment (Applicant Fierlinger, Peter )
• Experimental set-up and first measurements of the neutron lifetime using PENeLOPE (Applicant Paul, Stephan )
• Gravitational induced phase effects are investigated in neutron interferometry for testing the validity of the Newtonian potential (Applicant Zawisky, Michael )
• Investigations of magnetic field related systematic effects on the measurements of the electric dipole moment of the neutron in the OILL-Experiment (Applicant Gutsmiedl, Erwin )
• Koordinatorprojekt (Applicant Paul, Stephan )
• Low-energy proton detection using silicon drift detectors, and precision measurements of the proton asymmetry in neutron decay (Applicant Zimmer, Oliver )
• Magnetometry at the fTesla-scale for neutron EDM experiments (Applicant Heil, Werner )
• Magnetometry at the fTesla-scale for neutron EDM experiments using a co-habiting Xenon magnetometer based on free spin precession (Applicant Heil, Werner )
• Measurement of the neutron lifetime using a hybrid magnetic trap for ultra-cold neutrons (Applicant Zimmer, Oliver )
• Messung des gebundenen Betazerfalls freier Neutronen (Applicant Paul, Stephan )
• Neutron polarisation and polarisation analysis with 10-4 accuracy and design of the beam line for PERC (Applicant Soldner, Torsten )
• Neutron polarizer for PERC (Applicant Märkisch, Bastian Martin )
• PERC, a clean, bright and versatile source of neutron decay products (Applicant Märkisch, Bastian Martin )
• Performance of phase II of the project: Construction and performance of an experiment to determine a possible electric charge of the free neutron with a sensitivity of gamma qn = 10-22qe. (Applicant Reich, Tobias )
• Polarized ultra-cold neutrons in the next generation measurement of the neutron EDM (Applicant Fierlinger, Peter )
• Precision field characterization for the next generation measurement of the neutron EDM (Applicant Fierlinger, Peter )
• Precision magnetometry (Applicant Bison, Georg )
• Precision measurement of proton recoil spectrum and proton asymmetry in neutron decay using the spectrometer aSPECT (ILL contribution) (Applicant Zimmer, Oliver )
• Probing the electric neutrality of the neutron (Applicant Durstberger-Rennhofer, Katharina )
• Proton spectroscopy with PERC for precision measurements of the angular correlation coefficient alpha in neutron beta-decay (Applicant Heil, Werner )
• Realization of a magnetically shielded environment for a new measurement of the electric dipole moment of the neutron at the FRM-II and investigations of magnetic field related systematic effects (Applicant Fierlinger, Peter )
• Test of Gravitation with Quantum Objects by an Application of Ramsey´s Method of separated Oscillating Fields to Gravitationally Induced Quantum Phaseshifts (Applicant Abele, Hartmut )
• The electric field in the neutron EDM experiment (Applicant Gutsmiedl, Erwin )

• Spokesperson: Professor Dr. Stephan Paul