EPJ Web Conf.
Volume 219, 2019International Workshop on Particle Physics at Neutron Sources (PPNS 2018)
|Number of page(s)||9|
|Published online||12 December 2019|
Statistical sensitivity of the nEDM apparatus at PSI to n − n′ oscillations
1 University of Sussex, Brighton BN1 9RH, UK
2 Paul Scherrer Institute, 5232 Villigen, Switzerland
3 Marian Smoluchowski Institute of Physics, Jagiellonian University, 30-348 Kraków, Poland
4 Institute for Nuclear and Radiation Physics, KU Leuven, 3001 Heverlee, Belgium
5 Institute for Particle Physics and Astrophysics, ETH Zürich, 8093 Zürich, Switzerland
6 LPC Caen, ENSICAEN, Normandie Université, CNRS/IN2P3, 14000 Caen, France
7 Laboratoire de Physique Subatomique et de Cosmologie, 38000 Grenoble, France
8 University of Fribourg, 1700 Fribourg, Switzerland
9 Henryk Niedwodniczański Institute of Nuclear Physics, 31-342 Kraków, Poland
10 Laboratory for High Energy Physics and Albert Einstein Center for Fundamental Physics, University of Bern, 3012 Bern, Switzerland
11 Institut für Kernchemie, Johannes Gutenberg-Universität, 55128 Mainz, Germany
12 CSNSM, Université Paris Sud, CNRS/IN2P3, Université Paris Saclay, 91405 Orsay-Campus, France
13 Physikalisch Technische Bundesanstalt, 10587 Berlin, Germany
Published online: 12 December 2019
The neutron and its hypothetical mirror counterpart, a sterile state degenerate in mass, could spontaneously mix in a process much faster than the neutron β-decay. Two groups have performed a series of experiments in search of neutron – mirror-neutron (n − n′) oscillations. They reported no evidence, thereby setting stringent limits on the oscillation time τnn′. Later, these data sets have been further analyzed by Berezhiani et al.(2009–2017), and signals, compatible with n − n′ oscillations in the presence of mirror magnetic fields, have been reported. The Neutron Electric Dipole Moment Collaboration based at the Paul Scherrer Institute performed a new series of experiments to further test these signals. In this paper, we describe and motivate our choice of run configurations with an optimal filling time of 29 s, storage times of 180 s and 380 s, and applied magnetic fields of 10 μT and 20 μT. The choice of these run configurations ensures a reliable overlap in settings with the previous efforts and also improves the sensitivity to test the signals. We also elaborate on the technique of normalizing the neutron counts, making such a counting experiment at the ultra-cold neutron source at the Paul Scherrer Institute possible. Furthermore, the magnetic field characterization to meet the requirements of this n − n′ oscillation search is demonstrated. Finally, we show that this effort has a statistical sensitivity to n − n′ oscillations comparable to the current leading constraints for B′ = 0.
© The Authors, published by EDP Sciences, 2019
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