CryoEDM - The neutron Electric Dipole Moment experimental searches

          *** Instrument decommisionned in 2015 ***

It is a cryogenic experiment to search for the Electric Dipole Moment (EDM) of the neutron. The upper limit has been reduced by eight orders of magnitude in 50 years and the ILL recently sat the current experimental limit to |dn| < 2.9 x 10-26 e cm (90% CL). The CryoEDM project aims to a precision of 10-28 e cm.


The goal of CryoEDM is the measurement the neutron EDM to an unprecedented accuracy. Why is this important ?

CP violation is believed to be responsible for the baryon asymmetry of the Universe but the CP violation found in the Standard Model is many orders of magnitude too small to account for the observed baryon asymmetry. Extensions to the Standard Model of the electroweak interaction, such as additional Higgs fields, right-handed currents or supersymmetric partners typically give rise to dipole contributions which are of order 10-26 to 10-28 e cm.

Experimental measurements of particle EDMs, and in particular that of the neutron, are providing some of the strongest additional constraints on these theories.

A view of the cryoEDM instrument

The CryoEDM project aims to measure the neutron EDM to an unprecedented precision of 10-28 To achieve this, several parameters that determine the measurements sensitivity have been improved, the main characteristics is that it is operating entirely in a cryogenic environment.