Periodic Reporting for period 4 - BEAM-EDM (Unique Method for a Neutron Electric Dipole Moment Search using a Pulsed Beam)
Reporting period: 2021-10-01 to 2022-09-30
The BEAM-EDM project encompasses the research and application of novel precision methods in the field of low energy particle physics. The goal of the program is to lead an independent and highly competitive experiment to search for a CP-symmetry violating neutron electric dipole moment (EDM), as well as for new exotic interactions, employing highly sensitive neutron and proton spin resonance techniques.
The measurement of the neutron EDM is considered to be one of the most important fundamental physics experiments at low energy. It represents a promising route for finding new physics beyond the standard model (SM) and describes an important mechanism to understand the observed large matter/antimatter asymmetry in our universe. The project will follow a novel concept, which plans to employ a pulsed neutron beam at high intensity, instead of the established use of storable ultracold neutrons. This complementary method provides the possibility to distinguish between the signal due to a neutron EDM and previously limiting systematic effects, and should lead to an improved result compared to the present best neutron EDM beam experiment. The findings of these investigations will form the cornerstone for the success of a full-scale experiment intended for the European Spallation Source in Sweden.
A second scientific campaign focusing on the search for exotic short-range interactions and associated light bosons will be addressed by employing nuclear spin precession techniques. This is a burgeoning field of research motivated by various extensions to the SM. The goal of this project, using neutrons and protons, is to search for additional interactions between ordinary particles mediated by new bosons and for so-called dark-matter axions.
Both topics describe ambitious and unique efforts. They use related techniques, address important questions in fundamental physics, and have the potential of substantial scientific impact.
Both objectives of the project have been fulfilled. The novel technique has been varified and a preliminary measurement of the neutron EDM has been performed at the European neutron source Institute Laue-Langevin. Also the second task was very successful and we have used out neutron setup to search fo so-called axion-like particles and we have set up a low field NMR / proton Ramsey setup to search for exotic interactions.
The measurement of the neutron EDM is considered to be one of the most important fundamental physics experiments at low energy. It represents a promising route for finding new physics beyond the standard model (SM) and describes an important mechanism to understand the observed large matter/antimatter asymmetry in our universe. The project will follow a novel concept, which plans to employ a pulsed neutron beam at high intensity, instead of the established use of storable ultracold neutrons. This complementary method provides the possibility to distinguish between the signal due to a neutron EDM and previously limiting systematic effects, and should lead to an improved result compared to the present best neutron EDM beam experiment. The findings of these investigations will form the cornerstone for the success of a full-scale experiment intended for the European Spallation Source in Sweden.
A second scientific campaign focusing on the search for exotic short-range interactions and associated light bosons will be addressed by employing nuclear spin precession techniques. This is a burgeoning field of research motivated by various extensions to the SM. The goal of this project, using neutrons and protons, is to search for additional interactions between ordinary particles mediated by new bosons and for so-called dark-matter axions.
Both topics describe ambitious and unique efforts. They use related techniques, address important questions in fundamental physics, and have the potential of substantial scientific impact.
Both objectives of the project have been fulfilled. The novel technique has been varified and a preliminary measurement of the neutron EDM has been performed at the European neutron source Institute Laue-Langevin. Also the second task was very successful and we have used out neutron setup to search fo so-called axion-like particles and we have set up a low field NMR / proton Ramsey setup to search for exotic interactions.
During the first period of the project, the experimental apparatus for the neutron beam electric dipole moment measurement has been build at the University of Bern. This includes many dedicated precision components and developments, which are necessary to conduct the challenging project. During that period, my group has performed three each several-weeks-long neutron beam times at the Paul Scherrer Institute (PSI, Switzerland) and the Institute Laue-Langevin (ILL, France). From the measured data we could obtain valuable results which lead to improvments of our apparatus. The beam times also contributed to the hands-on education of students, PhD students and PostDocs. In the third period of the project a 35 days long measurement campaign at the Institute Laue-Langevin has been performed, where we first fully demonstrated the BEAM-EDM measurement concept with the full apparatus. Moreover, we performed a dedicated physics experiments, namely the search for axion-like particles (dark matter candidates). In the same period we successuflly set up the low field NMR / proton Ramsey apparatus to search for exotic interactions. The final period of the project we started publishing our results in scietific journals.
All our goals of the project have been achieved by the end of the project.