Wednesday 19 November 2008

Speaker: Maurits van der Grinten   (RAL)

Title: CryoEDM, a cryogenic experiment to search for the electric dipole moment of the neutron

Abstract: The search for the electric dipole moment (EDM) of the neutron plays a prominent role in
particle physics because of its direct bearing on CP and T violation: a non-zero value of the neutron
EDM would be evidence of CP and T violation. The neutron EDM is of particular interest because it is
very sensitive to CP violation beyond the Standard Model. The region that is probed by past experiments
is already putting tight constraints on models such as Supersymmetry, additional Higgs fields and
Left-Right symmetric models. 

We have constructed CryoEDM, an experiment designed to measure the neutron EDM to a precision of
10-28 e cm. The main characteristic is that it is operating entirely in a cryogenic environment, at
temperatures of 0.5K within superfluid helium. Ultracold neutrons are produced in a superthermal source
and stored within the superfluid in a storage cell which is held in a magnetic and electric field. NMR
measurements are carried out to look for any shifts in the neutron Larmor precession frequency
associated with the electric field. Low temperature SQUID magnetometry is used to monitor the magnetic
field.

I will report on the current status of the project that is now being commissioned and give an outlook
on the future exploitation of the instrument.