Search for macroscopic CP violating forces using a neutron EDM spectrometer
A. P. Serebrov, O. Zimmer+, P. Geltenbort+, A. K. Fomin, S. N. Ivanov, E. A. Kolomensky, I. A. Krasnoshekova, M. S. Lasakov, V. M. Lobashev, A. N. Pirozhkov, V. E. Varlamov, A. V. Vasiliev, O. M. Zherebtsov, E. B. Aleksandrov*, S. P. Dmitriev*, N. A. Dovator*
Petersburg Nuclear Physics Institute RAS, 188300 Gatchina, Leningrad District, Russia
+Institut Laue Langevin, BP 156, 38042 Grenoble, France
*Ioffe Physico-Technical Institute RAS, 194021 St. Petersburg, Russia
Abstract
The search for CP violating forces between nucleons in the
so-called axion window of force ranges λ between 2•10-5 m
and 0.02 m is
interesting because only little experimental information is available there.
Axion-like particles would induce a pseudo-magnetic field for neutrons close
to bulk matter. A laboratory search investigates neutron spin precession
close to a heavy mirror using ultracold neutrons in a magnetic resonance
spectrometer. From the absence of a shift of the magnetic resonance we
established new constraints on the coupling strength of axion-like particles
in terms of the product gsgp of scalar and pseudo-scalar dimensionless
constants, as a function of the force range
λ, [cm2]
(C.L.95
For 0.1 cm < λ < 1 cm previous limits are
improved by 4 to 5 orders of magnitude.