While the international nEDM collaboration at the Paul Scherrer Institut (PSI) took data in 2017 that covered a considerable fraction of the parameter space of claimed potential signals of ...hypothetical neutron (n) to mirror-neutron (n′) transitions, it could not test all claimed signal regions at various mirror magnetic fields. Therefore, a new study of n−n′ oscillations using stored ultracold neutrons (UCNs) is underway at PSI, considerably expanding the reach in parameter space of mirror magnetic fields (B′) and oscillation time constants (τnn′). The new apparatus is designed to test for the anomalous loss of stored ultracold neutrons as a function of an applied magnetic field. The experiment is distinguished from its predecessors by its very large storage vessel (1.47 m3), enhancing its statistical sensitivity. In a test experiment in 2020 we have demonstrated the capabilities of our apparatus. However, the full analysis of our recent data is still pending. Based on already demonstrated performance, we will reach sensitivity to oscillation times τnn′/cos(β) well above a hundred seconds, with β being the angle between B′ and the applied magnetic field B. The scan of B will allow the finding or the comprehensive exclusion of potential signals reported in the analysis of previous experiments and suggested to be consistent with neutron to mirror-neutron oscillations.
The pulsed neutron beam EDM experiment Chanel, Estelle; Hodge, Zachary; Ries, Dieter ...
EPJ Web of Conferences,
2019, Letnik:
219
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
We report on the Beam EDM experiment, which aims to employ a pulsed cold neutron beam to search for an electric dipole moment instead of the established use of storable ultracold neutrons. We present ...a brief overview of the basic measurement concept and the current status of our proof-of-principle Ramsey apparatus.
Zusammenfassung
Warum blieb nach dem Urknall nur Materie übrig? Dies ist eine der großen ungelösten Fragen der Physik. Eine mutmaßliche Ursache könnte eine starke Verletzung der sogenannten ...CP‐Symmetrie gewesen sein. Nach allgemeinen Prinzipien der Teilchenphysik müsste diese allerdings zu einem messbaren elektrischen Dipolmoment (EDM) von Elementarteilchen führen. Neutronen sind für die Suche nach EDMs besonders gut geeignet. Neue präzisere Daten lieferte jetzt das nEDM‐Experiment am Paul Scherrer Institut. Es senkte den Grenzwert für ein EDM von Neutronen erheblich. Der neue Messwert verschärft somit die Bedingungen für neue Theorien, die das Standardmodell erweitern. Der im Aufbau befindliche Nachfolger n2EDM soll 2022 in Betrieb gehen und als Ziel das Neutronen‐EDM zehnfach genauer bestimmen.
Warum blieb nach dem Urknall keine Antimaterie übrig? Dies ist eine der großen ungelösten Fragen der Physik. Eine mutmaßliche Ursache könnte eine starke Verletzung der sogenannten CP‐Symmetrie gewesen sein. Nach allgemeinen Prinzipien der Teilchenphysik müsste diese allerdings zu einem messbaren elektrischen Dipolmoment von Elementarteilchen führen. Neutronen sind für eine solche Messung besonders gut geeignet, erfordern aber hochempfindliche Präzisionsexperimente.
We report on a search for dark matter axion-like particles (ALPs) using a Ramsey-type apparatus for cold neutrons. A hypothetical ALP-gluon-coupling would manifest in a neutron electric dipole moment ...signal oscillating in time. Twenty-four hours of data have been analyzed in a frequency range from 23 $\mu$Hz to 1 kHz, and no significant oscillating signal has been found. The usage of present dark-matter models allows to constrain the coupling of ALPs to gluons in the mass range from $10^{-19}$ to $4 \times 10^{-12}$ eV. The best limit of $C_G$/$f_a m_a = 2.7 \times 10^{13}$ GeV$^{-2}$ (95% C.L.) is reached in the mass range from $2 \times 10^{-17}$ to $2 \times 10^{-14}$ eV.
Zusammenfassung
Warum blieb nach dem Urknall nur Materie übrig? Dies ist eine der großen ungelösten Fragen der Physik. Eine mutmaßliche Ursache könnte eine starke Verletzung der sogenannten ...CP‐Symmetrie gewesen sein. Nach allgemeinen Prinzipien der Teilchenphysik müsste diese allerdings zu einem messbaren elektrischen Dipolmoment (EDM) von Elementarteilchen führen. Neutronen sind für die Suche nach EDMs besonders gut geeignet. Neue präzisere Daten lieferte jetzt das nEDM‐Experiment am Paul Scherrer Institut. Es senkte den Grenzwert für ein EDM von Neutronen erheblich. Der neue Messwert verschärft somit die Bedingungen für neue Theorien, die das Standardmodell erweitern. Der im Aufbau befindliche Nachfolger n2EDM soll 2022 in Betrieb gehen und als Ziel das Neutronen‐EDM zehnfach genauer bestimmen.
A variety of experiments investigating properties of neutrons can be performed at pulsed reactor neutron sources like the research reactor TRIGA Mainz. A typical problem faced by these experiments is ...the non-availability of a reliable facility-provided trigger signal in coincidence with the neutron production. Here we present the design and implementation of a neutron pulse detector that provides a coincident trigger signal for experimental timing with a relative precision of 4.5 ms.
We report on a search for dark matter axion-like particles (ALPs) using a Ramsey-type apparatus for cold neutrons. A hypothetical ALP-gluon-coupling would manifest in a neutron electric dipole moment ...signal oscillating in time. Twenty-four hours of data have been analyzed in a frequency range from 23 \(\mu\)Hz to 1 kHz, and no significant oscillating signal has been found. The usage of present dark-matter models allows to constrain the coupling of ALPs to gluons in the mass range from \(10^{-19}\) to \(4 \times 10^{-12}\) eV. The best limit of \(C_G\)/\(f_a m_a = 2.7 \times 10^{13}\) GeV\(^{-2}\) (95% C.L.) is reached in the mass range from \(2 \times 10^{-17}\) to \(2 \times 10^{-14}\) eV.
The performance of the upgraded solid deuterium ultracold neutron source at the pulsed reactor TRIGA Mainz is described. The current configuration stage comprises the installation of a He liquefier ...to run UCN experiments over long-term periods, the use of stainless steel neutron guides with improved transmission as well as sputter-coated non-magnetic \(^{58}\)NiMo alloy at the inside walls of the thermal bridge and the converter cup. The UCN yield was measured in a `standard' UCN storage bottle (stainless steel) with a volume of 32 litres outside the biological shield at the experimental area yielding UCN densities of 8.5 /cm\(^3\); an increase by a factor of 3.5 compared to the former setup. The measured UCN storage curve is in good agreement with the predictions from a Monte Carlo simulation developed to model the source. The growth and formation of the solid deuterium converter during freeze-out are affected by the ortho/para ratio of the H\(_2\) premoderator.
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