Dear colleagues:

   Find below some minutes from today's meeting.

Carlos

----------------
Online: Charles, Malek, Pierre, Carlos.

- nDVCS proposal: Discussion on Malek's latest estimate of DVCS^2 with VGG
  model. Some issues raised on how could both the imaginary and real part
  of the DVCS amplitude be very small and, nevertheless, obtain a very
  large DVCS^2. This seems suspicious at this point and Malek is going to
  investigate further. Notice that at this point Malek is only including
  the 1st and 3rd terms of equation 66 in Belitsky's paper and neglecting
  the 2nd and 4th terms. To include the 2nd and 4th terms, we need the
  imaginary part of CFF Etilde which is not provided at this moment in the
  VGG code (I'll contact M. Guidal). Malek can at least include the first
  2 terms within the 2nd term (those not depending on Etilde), i.e. assume
  Etilde=0, but include _all_ terms depending on H, Htilde and E.

  General agreement on the need of two beam energies to separate the
DVCS^2 term regardless of VGG calculation (we cannot based our physics
results on the predictions of a model).

  Malek will continue working on the proposal by estimating the error bars
on the extraction of each coefficient when using two beam energies. For
the acceptance at 4.8 GeV he will, at least for the moment, use the same
simulation at 6 GeV and correct by hand the difference in the HRS momentum
bite. Other option is to use Pierre's fast simulation (B**h). Ideally (and
later), Franck would produce a Geant simulation at 4.8 GeV.

- nDVCS paper: Malek asked about showing Simonetta's prediction in the
  nDVCS paper. Pierre preferred not to. According to him, VGG model is
  shown to motivate the JuJd sensitivity whereas in Simonetta's model JuJd
  is fixed (and somehow taken from the lattice). Charles had not read
  Simonetta's paper and had not yet an opinion. I myself had no strong
  opinion either.

- Funding: Kees has a "small but non-negligible" chance of getting money
  to buy 100 PbF2 blocks beginning of August. Charles has asked Kees to
  ask Sirish for the specs of the previous order. No reply yet. Charles
  may contact Sirish directly. If JLab is buying the crystals, the request
  for a quote must be done by JLab. Charles will follow up on it.

  Side comment: Charles have asked Javier Gomez to be the physics liaison
for E07-007. No answer yet.

- pi0 analysis/paper: Pierre is still working on kin2 results. We will put
  the paper on hold for some more time.

- Some discussion on (prospective) students about timing and possible
  assignments. Also, Charles will probably send out a postdoc ad soon.


NEXT MEETING: Tuesday 7/31 at 10h/16h. Please join!
====================================================


On Mon, 23 Jul 2007, Carlos Munoz Camacho wrote:

>
> Dear colleagues:
>
>   Let's meet on Tuesday at 10h/16h for our "regular" DVCS meeting. On the
> menu:
>
> - nDVCS proposal
> - nDVCS paper
> - pi0 (analysis + paper status)
> - Funding
> - FEL tests and proposal
> - Any Other Business
>
>
> Carlos