Afach, S. Ban, Gert Bison, Georg Bodek, K. Burghoff, M. Daum, M. Fertl, M. Franke, B. Grujić, Zoran D. Hélaine, V. Kasprzak, Malgorzata Kermaïdic, Y. Kirch, K. Knowles, Paul E. Koch, Hans-Christian Komposch, S. Kozela, A. Krempel, J. Lauss, B. Lefort, T. Lemière, Y. Mtchedlishvili, A. Naviliat-Cuncic, O. Piegsa, F. M. Pignol, G. Prashanth, P. N. Quéméner, G. Rebreyend, D. Ries, D. Roccia, S. Schmidt-Wellenburg, P. Schnabel, A. Severijns, N. Voigt, J. Weis, Antoine Wyszynski, G. Zejma, J. Zenner, J. Zsigmond, G. 2015-05-18 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 Hg199 atoms confined in the same volume. The measurement was performed in a ∼1μT 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 gSgP. 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<λ<10−4m. application/pdf https://folia.unifr.ch/global/documents/304321 https://folia.unifr.ch/documents/304321/files/wei_cim.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.physletb.2015.04.024 info:eu-repo/semantics/openAccess License undefined Physics Letters B. - 2015, vol. 745, p. 58–63 CP violation Short range spin dependent interaction Axion Axion like particle Ultracold neutrons Neutron electric dipole moment info:eu-repo/classification/udc/53 Constraining interactions mediated by axion-like particles with ultracold neutrons http://purl.org/coar/resource_type/c_6501