Ok, forgot one thing:
-Eugene provided energy loss parametrizations for protons and residual
kinematic corrections from ep elastic scattering, all results are in a
ready-to-use code in the file KCORR.info (see meeting_060517 directory)
Regards,
Michael
On Sat, 20 May 2006, Michael Kohl wrote:
> Hi,
>
> below are the minutes of the analysis meeting from Wednesday 2006/05/17:
>
> Minutes:
> -Adrian has analyzed hPz vs. spin angle based on Hoehler form factors
> and v3_4_18, left/right sector equal hPz happens at 48.3 degrees in
> contrast to 47.5 degrees from Chris.
> -This was found for the lowest Q2bin, while Chris' estimate of the
> spin angle is for the entire Q2 distribution assuming Hoehler and a
> flat profile (correct, Chris?)
> -Extracted GE/GM from super ratio using hPz and th_s from first Q2
> bin. FF ratio as such quite similar to Hoehler ratio. Fourth Q2 point
> sits above Hoehler in AS's extraction, but below it in CC's
> -Needs to extract GE/GM by determining <th>_yield for each Q2bin in
> order to account for profile (like Chris).
> -Suggested to repeat spin angle extraction extended to first three
> bins, or to entire dataset and compare with the corresponding results
> from Chris to resolve observed discrepancy
> -Error analysis for theta_spin?
> -Spin angle from asymmetry at lowest Q2bin <th>_yield=48.3 corresponds
> to a nominal angle theta_nominal=49.3 degrees using Doug's profile,
> very consistent with Chi, but at odd with Chris.
>
> -Chi's latest extraction of <th>_yield from ed elastic asymmetries is
> 48.0 deg, effect of profile is <dth>_yield=-1.35 deg, corresponding
> to theta_nominal of 49.35 deg. Previous extraction was
> <th>_yield=47.7+-0.45, corresponding to theta_nominal=49.15+-0.45.
> This result would globally shift the maps of July 2004 by 0.8
> degrees, Jan2005 by 1.0 and of Jun2005 by 1.6 degrees to larger
> angles.
> So, the latest new extraction is so far consistent with the old
> although we need to wait for another recrunch iteration to obtain the
> final number. The error (+-0.45 deg) will not change. It consists of
> 0.42(stat), 0.12(recon), 0.01(false asymmetry), and 0.10(theo),
> i.e. is dominated by statistics
> -Extraction of theta from ed elastic not yet final, requires recrunch
> with data quality (timing calib) sufficient to use same cuts in Chi's
> analysis.
> -Previous attempt to provide such a recrunch (v3_4_19) with static
> timing failed for some reason, either timing really changed during
> the 2005 run, or timing calib was not as static as thought,
> investigating ...
> -Will recrunch 2005 deuterium data with static timing calib until mid
> next week, this would allow Chi to push the analysis button, get an
> appropriate event selection and extract <th>_yield for 47 degrees
>
> -Spin angle for 32degree setting can be considered final:
> From asymmetries: <th>_yield = 31.40 +- 0.43
> Av. profile effect on ed sample: <dth>_yield = -2.72
> "Nominal" spin angle at z=0: theta_nominal = 34.12 +- 0.43
> The uncertainty for theta_nominal is identical with the one from the
> asymmetry result and consists of 0.35(stat), 0.20(recon), 0.10(false
> asymmetry), and 0.10(theo), i.e. is dominated by statistics
>
> -People analyzing 32 degree data should use above theta_nominal along
> with Doug's averaged profile.
> This result would globally shift the maps of Jan2005 by 0.1 and of
> Jun2005 by 0.7 degrees to larger angles.
>
> 32 degrees setting:
> channel <th>_yield <dth>_yield theta_nominal(z=0) Comment
> d(e,e'd) 31.3(calc) -2.79(calc) 34.09(map) Jan2005 map
> 30.7(calc) -2.65(calc) 33.35(map) Jun2005 map
> ===================================================
> 31.4(asym) -2.79 34.19(calc) Jan2005 + 0.1
> -2.65 34.05(calc) Jun2005 + 0.7
> -2.72(av.) ->34.12(calc) DH's profile
> 31.7(old)
>
> ----------------------------------------------------------------
>
> d(e,e'n) 32.03(calc) -2.27(left) 34.12(ed) DH
> 31.88(calc) -2.42(right) 34.12(ed) DH
>
> ----------------------------------------------------------------
>
> 47 degrees setting: STILL TO BE UPDATED
> channel <th>_yield <dth>_yield theta_nominal(z=0)
> d(e,e'd) 47.0(calc) -1.5 (calc) 48.5 (map) Jul2004 map
> 46.8(calc) -1.22(calc) 48.02(map) Jan2005 map
> 46.2(calc) -1.32(calc) 47.52(map) Jun2005 map
> ===================================================
> 47.7(asym) -1.5 49.2 (calc) Jul2004 + 0.7
> (old) -1.22 48.92(calc) Jan2005 + 0.9
> -1.32 49.02(calc) Jun2005 + 1.5
> -1.35(av.) ->49.05(calc) DH's profile
>
> PRELIMINARY UPDATE:
> 46.8(calc) -1.22(calc) 48.02(map) Jan2005 map
> ===================================================
> 48.0(asym) -1.35(av.) ->49.35(calc) DH's profile
> ----------------------------------------------------------------
>
> Chris: no errors yet
> p(e,e'p) 45.8(asym) -0.8(calc) 46.6(calc) DH's profile???
> 47.5(old)
>
> Adrian: no errors yet
> p(e,e'p) 48.3(asym) -1.0(calc) 49.3(calc) DH's profile
>
>
> -Sasha Ilychev from Belarus likely to attend collaboration meeting on
> July 14, 2006 and to visit Bates for ~10 days. To arrive ~Tuesday
> before and to stay until ~Thursday thereafter.
> -Task is to implement Polrad (inclusive channel) properly into dgen,
> and also the code for exclusive pion production.
> -Relevant people should be prepared to spend a maximum amount of time
> with Sasha (Tavi,Yuan,Aki,Vitaliy,Michael,Doug,Renee,etc.)
>
> -No meeting on 5/24, next meeting instead on 5/31!
>
> Best regards,
>
> Michael
>
>
>
> +-------------------------------------+--------------------------+
> | Office: | Home: |
> |-------------------------------------|--------------------------|
> | Dr. Michael Kohl | Michael Kohl |
> | Laboratory for Nuclear Science | 5 Ibbetson Street |
> | MIT-Bates Linear Accelerator Center | Somerville, MA 02143 |
> | Middleton, MA 01949 | U.S.A. |
> | U.S.A. | |
> | - - - - - - - - - - - - | - - - - - - - - -|
> | Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de |
> | Work: +1-617-253-9207 | Home: +1-617-629-3147 |
> | Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 |
> | http://blast.lns.mit.edu | |
> +-------------------------------------+--------------------------+
>
>
>
>
>
>
> -d(e,e'p): kinematic corrections (AD)
> +Shows for each Q2bin comparisons of measured and simulated electron
> momentum. Differences are up to 2%, at the margin of the
> resolution. Pattern of deviations vs. Q2 is sector-symmetric
> +Note that definition of Q2 in q.e. scattering depends on two
> variables.
> +Shows comparison data/MC for quasifree (pm<0.15) events, expect
> events to be close to the elastic ridge in a p_e-vs-th_e plot,
> attribute deviation to either wrong th_e or p_e or both. Magnitude
> of deviation rather points to momentum (would require several degs.)
> +Parametrizes momentum corrections based on quasifree events
> (pm<0.15) as scale factor with linear dependence in Q2, plots
> measured minus expected electron momentum for entire q.e. event
> sample after applying this correction. Finds remaining deviations of
> ~7-10 MeV.
> +Comparison is new 2004 recrunch v3_4_17 with an older MC which uses
> old geometry however we're looking at physical variables here
> +New MC still has the problem of disappearing yield at small
> angles. There seems to be a dependence on computer architecture
> (=initialization problem?)
>
> Suggestions:
> +Should apply corrections from ep elastic (Eugene's) to see how well
> they work
> +New MC should make use of spin angle profile
> +Adam: could you also evaluate the target yield-weighted average for
> given spin angle maps, for the d(e,e'p) event sample (see
> discussion on spin angle in separate email)
>
> -Spin angle:
> +No estimate yet of the error of the average spin angle extracted
> from ep elastic asymmetries.
> +Strong dependence on reconstruction likely explains large shift of
> the spin angle recently reported
> +Remember, in the hPz-vs-th_s plot, the two straights for the two
> sectors are almost collinear, while the slopes of the two crossing
> straights in the corresponding Pzz-vs-th_s plot from ed elastic
> have opposite signs, making ed elastic much more robust in
> determining the spin angle against changes in reconstruction.
> +For extraction of form factor ratio, needs to account for profile in
> extraction of observables, use "nominal" spin angle determined by
> Chi (on "average" vs. "nominal" see separate message)
> +Shows target z-distribution of ep elastic yield broken down in
> Q2bins. Not all bins are distributed as naively expected, pointing
> to residual reconstruction errors
> +Shows the same with spin angle profile overlayed and the resulting
> yield-weighted average for each Q2bin. The latter does not(!) vary
> much (<0.2deg) around the yield-weighted average of the entire data
> sample, but note that the z coordinate reconstructed from data may
> not fully reflect reality.
> +Suggestion: Does this negligible variation of yield-weighted
> averages for various Q2bins also hold for MC-generated ep elastic
> target-z yield distributions?
>
> Best regards,
>
> Michael
>
>
> +-------------------------------------+--------------------------+
> | Office: | Home: |
> |-------------------------------------|--------------------------|
> | Dr. Michael Kohl | Michael Kohl |
> | Laboratory for Nuclear Science | 5 Ibbetson Street |
> | MIT-Bates Linear Accelerator Center | Somerville, MA 02143 |
> | Middleton, MA 01949 | U.S.A. |
> | U.S.A. | |
> | - - - - - - - - - - - - | - - - - - - - - -|
> | Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de |
> | Work: +1-617-253-9207 | Home: +1-617-629-3147 |
> | Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 |
> | http://blast.lns.mit.edu | |
> +-------------------------------------+--------------------------+
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
+-------------------------------------+--------------------------+
| Office: | Home: |
|-------------------------------------|--------------------------|
| Dr. Michael Kohl | Michael Kohl |
| Laboratory for Nuclear Science | 5 Ibbetson Street |
| MIT-Bates Linear Accelerator Center | Somerville, MA 02143 |
| Middleton, MA 01949 | U.S.A. |
| U.S.A. | |
| - - - - - - - - - - - - | - - - - - - - - -|
| Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de |
| Work: +1-617-253-9207 | Home: +1-617-629-3147 |
| Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 |
| http://blast.lns.mit.edu | |
+-------------------------------------+--------------------------+
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