1. Constraining interactions mediated by axion-like particles with ultracold neutrons
- Author
-
Afach S., Ban G., Bison G., Bodek K., Burghoff M., Daum M., Fertl M., Franke B., Grujic Z.D., Hélaine V., Kasprzak M., Kermaïdic Y., Kirch K., Knowles P., Koch H.-C., Komposch S., Kozela A., Krempel J., Lauss B., Lefort T., Lemière Y., Mtchedlishvili A., Naviliat-Cuncic O., Piegsa F.M., and Pignol G.
- Abstract
We report a new limit on a possible short range spin dependent interaction from the precise measurement of the ratio of Larmor precession frequencies of stored ultracold neutrons and Hg 199 atoms confined in the same volume. The measurement was performed in a ~ 1 µT vertical magnetic holding field with the apparatus searching for a permanent electric dipole moment of the neutron at the Paul Scherrer Institute. A possible coupling between freely precessing polarized neutron spins and unpolarized nucleons of the wall material can be investigated by searching for a tiny change of the precession frequencies of neutron and mercury spins. Such a frequency change can be interpreted as a consequence of a short range spin dependent interaction that could possibly be mediated by axions or axion like particles. The interaction strength is proportional to the \{CP\} violating product of scalar and pseudoscalar coupling constants g S g P . Our result confirms limits from complementary experiments with spin polarized nuclei in a model independent way. Limits from other neutron experiments are improved by up to two orders of magnitude in the interaction range of 10 - 6 lt; ? lt; 10 - 4 m .
- Published
- 2015