Minutes of the analysis meeting on 10/18/2005

From: Michael Kohl (kohlm@blast05.lns.mit.edu)
Date: Wed Oct 19 2005 - 16:34:28 EDT


Hi,

in the meeting yesterday we
  - went through Eugene's plots from Monday night
  - talked about momentum resolution
  - talk briefly about maid2003
  - listened to Taylan's talk on GE/GM to be given at PANIC05

We concluded the day at UNH attending and celebrating Peter's successful
defense.

On Eugene's plots:
Things are really not conclusive if proper cuts are not applied. When one
wants to compare quasifree (e,e'n) yields from 2004 and 2005, good cuts
are needed for both datasets, and then yield ratios of charge-normalized
yields of 2004 versus 2005 are required in order to tell how the drop of
rates is manifest *quantitatively*.
It's good to see where "wholes" may be or may not be, but it needs to (and
can be) quantified. The same is true for the recent wire chamber plots.

One question has been originally if a possible "TOF-inefficiency", along
with the charge miscalibration for the 2005 runs before 15214, fully
accounts for the observed drop of yields.

We do not understand the large yield that the plots show for the last
dataset in 2004 (the blue one). Vitaliy's (e,e'n) rate monitor vs.
run number showed something different, much less exceptional.

On momentum resolution:
  - In e,e'n VZ sees a worse resolution (width of the quasielastic peak in
    the W-Spectrum towards higher Q2, exceeding the Fermi-broadening
  - Not confirmed by the elastic peak in ed-elastic (CZ), however the
    phase-space (or electron angle-momentum combination) in ed elastic is
    different from e,e'N quasielastic.
  - The worse resolution at higher Q2 should be apparent in ep elastic
    (Chris, Adrian?), which covers a similar region of angle and momenta
    compared to quasielastic. If people could comment ...

On Maid2003:
  - CZ and YX debugging implemented code
  - maid2003 code consistent with maid website
  - events presently generated according to cross section
  - suggested to use white generator instead according to pion
    production phase space. For the once generated event list, events can
    be weighted according to maid. maid2003 allows for a variation of
    input parameters such as switchjes for resonances. With the white
    generator effect of these input parameters can be convoluted with BLAST
    acceptance and studied in detail.

Regards,

    Michael

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On Wed, 19 Oct 2005, Eugene J. Geis wrote:

>>>> I sent this last night but never got it in my own inbox, so I was wondering if it got lost or filtered.
> Sorry if you've gotten it already.
>
> eugene
> ==============================================
>
> It seems as though there might be a bit of a falloff in the WireChambers in the
> left sector which might
> correspond to the region of TOF 6-9. I have 2 plots. One is labeled
> 2004_efficiency.pdf The other is
> 2005_inefficiency.pdf. They are plots of the wire chambers. They are 3D and
> are somewhat close to
> the geometry of the wire chambers (aside from a reflection through the BLAST x-y
> axis). The window in
> the 40-50 degree region in the WC is extremely obvious. The runs used in this
> analysis for 2005 are
> 14486-14493. The runs used for 2004 are 11487-11493. The height is the number
> of hits in cells
> that had tracks. the x and y are 0-35 for the 35 cells and 0-5 for the 6
> superlayers.
>
> Again, I think we can conclusively say that the wire chambers show a hole...
> maybe because of TOF
> inefficiency... The right side is consistent in both years' datasets.
>
> I've included one more postscript entitled 2004_left for a more obvious overhead
> view of the 3D plot.
> I hope these are understandable.
>
> eugene
>
> --------------------------------------------------------------------------
> Eugene Geis
> PhD Student, Physics Department, ASU
> Research Affiliate, MIT-Bates Laboratory of Nuclear Science
> eugene.geis@asu.edu
> --------------------------------------------------------------------------
> http://quickreaction.blogspot.com
> ----- End forwarded message -----
>
>
>
> --------------------------------------------------------------------------
> Eugene Geis
> PhD Student, Physics Department, ASU
> Research Affiliate, MIT-Bates Laboratory of Nuclear Science
> eugene.geis@asu.edu
> --------------------------------------------------------------------------
> http://quickreaction.blogspot.com
>



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