Comparison of ultracold neutron sources for fundamental physics measurements

Ultracold neutrons (UCNs) are key for precision studies of fundamental parameters of the neutron and in searches for new CP violating processes or exotic interactions beyond the Standard Model of particle physics. The most prominent example is the search for a permanent electric dipole moment of the neutron (nEDM). We have performed an experimental comparison of the leading UCN sources currently operating. We have used a 'standard' UCN storage bottle with a volume of 32 liters, comparable in size to nEDM experiments, which allows us to compare the UCN density available at a given beam port.Comment: 20 pages, 30 Figure

Search for an electric charge of the neutron

International audienceThe electrical neutrality of the neutron is linked to the electric charge quantization. It is not understood yet if the electric charge is quantized or not. Since the discovery of the neutron, many attempts have been made to measure its electric charge qn directly and indirectly. We present a method to search for a possible qn by means of an optical setup using ultracold neutrons. In a first run, a statistical sensitivity of δqn=2.4×10-20  e/day is achieved. Possible improvements to increase this sensitivity down to δqn≈1×10-21  e/day are found and discussed