>
> Hi Boss, will the lunch be provided? :)
I believe so. I can cook some beforehand if that makes you feel better
> seriously, the things I got asked about this morning at meeting.
>
> 1. in terms of the errors between 32 and 45 deg runs. turns out with 45(or
> 47 or whatever in that neighborhood), errors on T20 are only marginally
> better than with 32 deg. we are talking about +-0.15 vs +-0.14 type of
> difference.
Well, from genya I got a quite different answer. Do not plan to solve this
over email
> 3. a spin angle profile as seen by ed elastic. please see the attatched
> plot. the black curve is the "scaled to 32 deg" profile. It takes the 47
> degree profile, scaled the tangent of angle at any point by
> tan(32)/tan(47). the purple data points are spin angle measured from ed
> elastic by cutting the target length into intervals. the division of the
> -20 to 20cm range is such that each interval contains roughly equal
> counts. data seem to want to dip more. I say we should let a actual survey
> speak.
Well, if I could fit the black data I could do a weighted integral with
the cell density
> To beat on actual survey, I still believe the field mapping is THE right
> way to control spin angle. T20 measurement or whatever measurement from data
> should be taken only to monitor and/or confirm the survey result and to
> make sure that problems would be quickly spotted if there were any
> problems, such as a shorted coil, which motivated the T20 spin angle
> measurement ealier in 2004 anyway.
Exactly. Even if you know the "average spin angle", so what ? You still
have to do an event by event correction eventually, which is z dependent.
I think I somehow overlooked this and let the discussion grow.
And I also think it yields on the systematic error discussion. The
estimation based on the error bar on the average angle may not mean much.
It is more instructive to redo the analysis changing the spin angle
profile in some fashion (with this map, you could systematically shift
the field profiles +- 5 gauss up or down, which still is close to 1%
variation and is comparable to the size one of your purple error bar).
> About the event by event correction of spin angle. it is done in ed
> elasitc channel with the "fudged" angle profile. All the programs and
> infrastructures are constructed months ago, the one single missing
> piece is the map.
thanks, we all agree I think. Now, what is the Pzz profile from your
data ?
> Chi
>
> On Wed, 19 Jan 2005, Tancredi Botto wrote:
>
> >
> > Following today's discussion I suggest an agenda for our meeting with
> > D. Philips next week, assuming we have regular blast meeting at 9.00.
> >
> > Maybe D. Philips talk could be anticipated to 13.30 to suit Richard
> > travel needs. Let me know what you think.
> >
> >
> > 10.30 AM: Overview BLAST detector, BLAST spin dependent eep asymmetries vs
> > pmiss
> > 10.45 VZ: GEn measurament
> >
> > 11.00 CZ: BLAST T20 measurament, and discussion of its normalization
> >
> > 12.00 Lunch (Bates library)
> >
> > 14.00 D. Philips talk
> >
> > 15.00 General discussion
> >
> > --
> > ________________________________________________________________________________
> > Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
> > research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >
> >
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