Fundamental Physics with Ultracold Neutrons at LANL
ORAL · Invited
Abstract
The DOE nuclear physics program at Los Alamos left a legacy of experimental facilities at Los Alamos Neutron Science Center LANSCE. This enables important applied work such as that at the proton radiography facility as well as enabling the development of a facility using ultra cold neutrons (UCN) for studies of neutron beta decay among other topics. This began with experiments studying the science of UCN production in solid deuterium.[1] These results led to the development and construction of the most intense UCN source in the world at Los Alamos Neutron Science Center.[2] Experiments performed using this source are providing sensitive tests of the unitarily of the top row CKM matrix by providing the most precise measurement of the neutron lifetime[3] and important measurements of the A0 parameter in neutron beta decay.[4] New experiments are underway to measure the neutron electric dipole moments, the neutron lifetime and A0 all to precisions that exceed current measurements and that will provide stringent tests of the standard model of particle physics. Work is underway to boost the source output by a factor of ten to enable world leading precision for all these experiments. The development and status of this program will be presented.
1. Morris, C., et al., Measurements of ultracold-neutron lifetimes in solid deuterium. Physical review letters, 2002. 89(27): p. 272501.
2. Ito, T.M., et al., Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment. Physical Review C, 2018. 97(1): p. 012501.
3. Musedinovic, R., et al., Measurement of the free neutron lifetime in a magneto-gravitational trap with in situ detection. Physical Review C, 2025. 111(4): p. 045501.
4. Brown, M.-P., et al., New result for the neutron β-asymmetry parameter A 0 from UCNA. Physical Review C, 2018. 97(3): p. 035505.
1. Morris, C., et al., Measurements of ultracold-neutron lifetimes in solid deuterium. Physical review letters, 2002. 89(27): p. 272501.
2. Ito, T.M., et al., Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment. Physical Review C, 2018. 97(1): p. 012501.
3. Musedinovic, R., et al., Measurement of the free neutron lifetime in a magneto-gravitational trap with in situ detection. Physical Review C, 2025. 111(4): p. 045501.
4. Brown, M.-P., et al., New result for the neutron β-asymmetry parameter A 0 from UCNA. Physical Review C, 2018. 97(3): p. 035505.
*This work was supported by the U.S. Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001) and by the Los Alamos LDRD program.
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Presenters
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Christopher Lee Morris
- Los Alamos National Laboratory (LANL)