Dear Dr. Schietinger,

Congratulations on your talk on the EDM proposal at PSI ..... very interesting.  Thank goodness 
someone is taking the muon g-2 discrepancy seriously.  As you indicate, a tilt of 2 mR in the 
precession plane would explain our result and an EDM this size would be sensational.  But the 
theorists have often been wrong before. At your slower velocity the vertical EDM precession 
would be 1/600 of the g-2 frequency ....... and this could well be detectable , especially with 
the frozen spin technique.

If you find this EDM, those who refuse to acknowledge that we have a discrepancy will be the 
first to claim "we saw it first" ! !

Here are a few comments on your proposed experiment, which may be useful.

* The best data statistically comes from about 2 lifetimes and the value falls slowly beyond 
  that.  So it would pay you to take data for 3 lifetimes, maybe a little more.  That is 10 
  microsec or more. So you should allow 10 microsec or more between injections.

* Your magnet has a huge fringing field and this will make it difficult to inject.  Also the 
  proposed injection by horizontal resonance is exceedingly tricky and the phase space 
  acceptance for injection will probably be microscopic.  Have you considered a racetrack 
  storage ring, with strong focusing and 2 or 3 straight sections??  (2 is usually unstable).  
  There is of course no need to measure the field accurately; it is calibrated by g-2.  The 
  straights will dilute the average field, but you can compensate by increasing the field in 
  the bends.  Then you can use the straights for injection with a rather standard kicker.

* Yes, the orbit period is about 10 ns, so the kicker will have to turn off very fast; but 
  this might be do-able, as the energy required is quite low.  Volts x amps is of order 
  (energy stored in the magnet)/(fall time).  If you inject mu+ and mu-, clockwise and 
  anticlockwise, in alternate pulses, you would give the kickers more time to recover.

* Then you could store more muons and also might inject several muons on each fill.

* Note that Orlov has determined that the radial E field must coincide with the bending field, 
  otherwise you can get errors.

* A huge advantage of this "table top" apparatus is that it can be mechanically solid and very 
  stable, so the vertical component of the E-field (if any) can be kept constant.  Drift of 
  the electric field angle relative to the direction of the magnetic field is one of the major 
  concerns in this type of experiment.

Hoping these remarks may be of interest, and wishing you every success in your experiment .......... Francis

-- 
Francis Farley
8 Chemin de Saint Pierre
06620 Le Bar sur Loup
France

Tel:   33-(0)4 93 42 45 12

email:  fjmfarley@neuf.fr

Everything will be all right in the end.
If it's not all right, it's not the end.