[Frost] One more thing on tagger sag
Sungkyun Park
sp06k at fsu.edu
Mon Jun 28 16:57:44 EDT 2010
Michael,
I make histogram to check the tagger sag condition in FROST data.
I have used all runs in the period 3 (E_e = 1.645 GeV) to make a histogram in the following web:
http://hadron.physics.fsu.edu/~skpark/research/research_jun2810.html
In the first sag position, there are some vibrations but the second sag do not have any sag.
How do you think?
After copying runs in the period 7 (E_e = 2.478 GeV) , I will make the same histogram like the upper one.
I will start the momentum correction using the data of the CH2 target in the period 7 (E_e = 2.478 GeV).
For this, I define new binning of phi, theta, momentum like :
http://hadron.physics.fsu.edu/~skpark/research/research_jun1510_FROST.html
The main reason which I define like the upper web is the number of events.
Now I use the data of the topology gamma p -> p pi+ pi- for momentum correction. However their number of events are very small per run. Thus I reduce the number of binning for the good gaussian fitting.
You also start the momentum correction for FROST soon. If we can use the same binning , we can share our results together. Can I know your opinion about my binning?
I will start the momentum correction after copying all runs of the period7 to FSU.
Best wishes
Sungkyun Park
Florida state University
----- Original Message -----
From: Michael Dugger <dugger at jlab.org>
Date: Wednesday, June 16, 2010 6:10 pm
Subject: One more thing on tagger sag
To: Sungkyun Park <sp06k at fsu.edu>
Cc: frost at jlab.org
>
> Sungkyun,
>
> For g1c, the local minima for the tagger sag correction happened at
> roughly 0.42 E_e and 0.74 E_e (where E_e = 3.115 GeV). This would
> correspond to local minima being at about 0.69 GeV and 1.21 GeV for
> your
> data (E_e = 1.645 GeV). Your binning in photon energy is not as
> fine as
> what we have used in the past, but it looks like you have local
> minima at
> about 1.25 GeV, and there is not enough bins or statistics to see
> if there
> is a local minima at ~0.7 GeV. Is it possible for you to increase
> the
> statistics and bin finer in photon energy?
>
> When I did the g8b photon energy correction, I had to use the
> entire
> amorphous set to get the needed statistics.
>
> Another thing to consider:
> It might be best to use data from the 2.478 GeV set. This will give
> you a wider range of the tagger when using the reaction gamma p ->
> p pi+
> pi-. Also, your momentum corrections will have a better range of
> validity
> if you use the 2.478 GeV data set.
>
> -Michael
>
> On Wed, 16 Jun 2010, Sungkyun Park wrote:
>
> > Michael,
> >
> > I find some mistakes in my last updated plots. When I project
> histograms, I used the wrong plots.
> > I make the same histograms like before again after correcting
> my mistakes:
> >
> http://hadron.physics.fsu.edu/~skpark/research/research_jun1410.html>
> > I also start to look the momentum correction for FROST.
> > We can share some idea together. To do this, we need to fix the
> bins range.
> >
> > I mean g8b used the definition of the following bins.
> >
> > proton
> >
> > * ? 1 - 7, 10 degrees each bin
> > * ? 1 - 18, 20 degrees each bin
> > * momentum
> > mom01 = [0.2 - 0.45], mom02 = [0.45 - 0.7], mom03=[0.7 -
> 0.95], mom04=[0.95 - 1.2], mom05=[1.2 -1.45], mom06=[1.45 - ]
> >
> > pion
> >
> > * ? 1 - 14, 10 degrees each bin
> > * ? 1 - 18, 20 degrees each bin
> > * momentum
> > mom01=[0.05 - 0.3],mom02=[0.3 - 0.55],mom03=[ 0.55 -
> 0.8],mom04=[0.8 - 1.05],mom05=[1.05 - 1.3],mom06=[1.3 -
> 1.55],mom07=[1.55 - 1.80],mom08=[1.80 - ]
> >
> > we need to decide to use the same bin distribution of g8b or
> another group or make our bins.
> > I have one suggestion about the bin distribution for FROST
> >
> >
> http://hadron.physics.fsu.edu/~skpark/research/research_jun1510.html>
> > Let me know your idea.
> >
> > Best wishes
> > Sungkyun Park
> > Florida State University
> >
> > ----- Original Message -----
> > From: dugger at jlab.org
> > Date: Monday, June 14, 2010 10:39 pm
> > Subject: Re: [Frost] tagger sag
> > To: Sungkyun Park <sp06k at fsu.edu>
> > Cc: dugger at jlab.org, frost at jlab.org
> >
> >> Sungkyun,
> >>
> >> I am sorry.
> >>
> >> I did not understand what was shown.
> >>
> >> At first glance, it looks like the tagger sag is correctly dealt
> >> with. The
> >> error bars are still a bit large. If I read your CH2 (eloss
> corrected)>> plot correctly, it looks like the energies are within
> +/- 0.5%.
> >> There is
> >> not enough photon energy bins to see if there is the 3 bump
> structure.>>
> >> If we assume that the tagger sag has been dealt with, then the next
> >> thingis to find the momentum corrections.
> >>
> >> I got an email from Brian Vernarsky today. He stated that he is
> >> ready to
> >> start looking at the energy and momentum corrections for g9. He has
> >> hiscode working for g1c. With any luck we should get some
> >> correction factors
> >> for g9 soon.
> >>
> >> I apologize for the confusion.
> >>
> >> Sincerely,
> >> Michael
> >>
> >>
> >>
> >>
> >>
> >>> Hi Michael,
> >>>
> >>>> Unless the photon pulls are better than you have previously
> >> reported, the
> >>>> energy differences shown can not be taken as accurate. This
> >> means that
> >> I do not know what to say regarding your most recent plots.
> >>>
> >>> I do not understand why you say about the photon pull with my
> >> yesterday's
> >>> plots.
> >>> I do not use any kinematic fitting term in my yesterday's plots.
> >> I only
> >> follow your suggestion to check if the tagger sag is correctly
> >> includedin g9a.
> >>> Thus, I make histograms with [E_calculated -
> >> E_measured]/E_measured and
> >> enough statistics to get
> >>> the numbers to the 0.1 % level.
> >>>
> >>> My understanding is that the kinematic fitter need to have
> >> momentum as
> >> the
> >>> initial value and it correct momentum using energy conservation.
> >> In this
> >> case, the initial energy is very important factor.
> >>>
> >>> Before kinematic fitting, the momentum can be corrected by using
> >> severalcorrection. now I used eloss correction and will use
> >> momentum correction
> >> for g9a.
> >>>
> >>> Unfortunately, after applying the eloss correction, the pull
> >> distribution
> >>> in butanol target is still very bad.
> >>> I am not sure if our eloss package correct momentum and to
> check the
> >> effect of our eloss package, I make the plot with the ratio of the
> >> calculated photon E to measured photon E.
> >>>
> >>> If in my yesterday' plot, we can not check the problem of the
> tagger>> sag,
> >>> what do I make to check them?
> >>> It is also important to check if we have the problem of the
> >> tagger sag now.
> >>> I think in the current status, we can not use the result of the
> >> kinematic
> >>> fitting.
> >>>
> >>> How do you think that I add the code to correct the tagger sag
> >> from g8b
> >> in
> >>> my analysis code and I make some plots to compare?
> >>>
> >>> Sung
> >>> Florida State University
> >>>
> >>>> Chuck had stated that the pull parameters are going to give you
> >> moremeaningful information than the corrected energy. He should
> >> know. Why
> >> don't you do as he suggested, and show the center of the photon
> pulls>> as a
> >>>> function of photon energy?
> >>>> Of course you are free to feel confident in the corrected
> values of
> >> thephoton energy given by your kinematic fitter. It is up to you to
> >> find out
> >>>> how best to make the photon pull parameters more reasonable. I
> >> wouldconcentrate on the easiest thing first: Make the Carbon and
> CH2>> targetshave reasonable pulls, and then work on the Butanol
> target.>> Thatis just
> >>>> me. It is your analysis.
> >>>> Happy hunting.
> >>>> Best wishes,
> >>>> Michael
> >>>>> Hi Dugger,
> >>>>>
> >>>>> I have made more updated histograms.
> >>>>> The y-axis value has [E_calculated - E_measured] /
> >> [E_measured] The
> >> x-axis has [E_measured] or Z-vertex.
> >>>>> You can check my results in the following web:
> >>>>>
> >>>>> http://www.jlab.org/Hall-B/secure/g9/sungkyun/6-14-10.html
> >>>>>
> >>>>> I am sure that after applying the recent updated eloss
> >>>> correction, the
> >>>>> ratio of {E(cal. photon) - E(cal. photon)} to E(cal. photon) has
> >>>> been> located near zero more. I think the current eloss is
> >> improved more.>
> >>>>> I do not know about the tagger sag. After eloss correction,
> there>>>> are> still structure. that is, In the low energy,
> measured photon
> >> energy is
> >>>>> bigger than calculated photon energy. However, the difference is
> >>>> very> small when we compare them with the histogram which are
> made>> before eloss.
> >>>>> Do you think the reason of this difference is the tagger sag?
> >>>>>
> >>>>> Sung
> >>>>>
> >>>>> Florida State University
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> ----- Original Message -----
> >>>>> From: Michael Dugger <dugger at jlab.org>
> >>>>> Date: Wednesday, June 9, 2010 4:34 pm
> >>>>> Subject: Re: [Frost] tagger sag
> >>>>> To: Sungkyun Park <sp06k at fsu.edu>
> >>>>> Cc: frost at jlab.org
> >>>>>
> >>>>>>
> >>>>>> Sung,
> >>>>>>
> >>>>>> I really hate to be a bother. From what I can tell, the plots
> >> youshow are
> >>>>>> from the kinematic fitter. The FSU kinematic fitter showed
> >> the exact
> >> same
> >>>>>> kind of agreement for g8b. I do not know why. There were many
> >> discussions regarding this. Please see
> >>>>>> http://www.jlab.org/~dugger/tmp/meanValues_048326.A10.gif
> >> (this plot
> >> goes
> >>>>>> along with the email I got from Charles Hanretty shown at the
> >> bottom of
> >>>>>> this email). Charles and I had the exact same conversations
> >>>>>> regarding the
> >>>>>> tagger sag for g8b.
> >>>>>>
> >>>>>> The pull parameters for the photon energy are a much better
> >> gauge of
> >> how
> >>>>>> well the measured photon energy compares to the calculated
> >> when using a
> >>>>>> kinematic fitter. A kinematic fitter can not be relied upon
> >> to give
> >> accurate results when the pulls are not close to optimal. This
> >> appears to
> >>>>>> very much the case for the calculated photon energy using the
> >> FSUkinematic fitter for g8b (and probably for g9a as well).
> >>>>>>
> >>>>>> You can see the difference in the pull parameters before and
> >> after the
> >>>>>> tagger sag correction for g8b data in Fig. 7 on page 8 of
> >>>>>> http://www1.jlab.org/ul/Physics/Hall-B/clas/public/2009-030.pdf
> >>>>>>
> >>>>>> Your photon pulls shown on your web page at:
> >>>>>> http://www.jlab.org/Hall-B/secure/g9/sungkyun/6-1-10.html
> >>>>>> Give the following parameters:
> >>>>>>
> >>>>>> Carbon->
> >>>>>> mean 0.122
> >>>>>> sigma 1.124
> >>>>>>
> >>>>>> CH2->
> >>>>>> mean 0.251
> >>>>>> sigma 1.235
> >>>>>>>>>>> For Chuck using g8b data:
> >>>>>>
> >>>>>> Before tagger sag correction->
> >>>>>> mean 0.3027
> >>>>>> sigma 1.219
> >>>>>>
> >>>>>> After tagger sag correction->
> >>>>>> mean 0.0049
> >>>>>> sigma 1.040
> >>>>>>
> >>>>>> At first glance, it looks entirely reasonable to suspect that
> >> youhave the
> >>>>>> same sort of photon energy problems that Chuck had.
> >>>>>>
> >>>>>> I also want to make it clear that the sag correction was
> >> supposed to be
> >>>>>> included in the g8b data and it was never determined what went
> >> wrong. Why
> >>>>>> should we assume that the tagger sag is fixed when it has not
> >> beenverified?
> >>>>>>
> >>>>>> One more thing that might be of interest: It appears that the
> >> [E_calculated - E_measured] is nearly perfect for the comparisons
> >> done by the kinematic fitter. However, it would be very surprising
> >> to get
> >>>>>> this same type of result from your most recent study at:
> >>>>>> http://www.jlab.org/Hall-B/secure/g9/sungkyun/6-9-10.html
> >>>>>>
> >>>>>> I only propose that you find out [E_calculated -
> >>>>>> E_measured]/E_measured using your most current study (without
> >> kinematic>> >> fitter) and include enough statistics to get the
> >> numbers to the 0.1%
> >>>>>> level. This would serve as a way to verify that the tagger
> >> sag is
> >> correctly included in g9a.
> >>>>>>
> >>>>>> No matter what, you are going to have to get your photon
> >> pulls to be
> >> much
> >>>>>> better before you can reliably use the kinematic fitter in your
> >> analysis.
> >>>>>> That is the price you pay for using such a powerful technique.
> >>>>>>
> >>>>>>
> >>>>>> ************************
> >>>>>> Date: Wed, 19 Aug 2009 15:18:41 -0400 (EDT)
> >>>>>> From: Charles Hanretty <hanretty at hadron.physics.fsu.edu>
> >>>>>> To: Michael Dugger <dugger at jlab.org>
> >>>>>> Subject: Re: E(true) and E(meas)
> >>>>>> Parts/Attachments:
> >>>>>> 1 Shown 161 lines Text
> >>>>>> 2 OK 12 KB Image
> >>>>>> ----------------------------------------
> >>>>>>
> >>>>>> Mike,
> > >> >> Attached is a plot I have of the mean values generated from
> >>>>>> just 1
> >>>>>> 1.3GeV file
> >>>>>> (cooked_048326.A10.B00). I fit each slice of the
> >>>>>> (Etrue/Emeas)vEmeas plot
> >>>>>> by using the function
> >>>>>> TH2::FitSlicesY (168 slices). Looking at this, one could see
> >> thesimilarity between this plot and
> >>>>>> the one you showed at the meeting. I've made this final plot
> >> (Etrue-Emeas v Emeas) but it does not look how I expect it to or
> >> want it
> >>>>>> to
> >>>>>> so I'm trying to figure out if I made an error somewhere.
> >> One thing to
> >>>>>> note
> >>>>>> is that the differences between Etrue and Emeas (for me) seem
> >> to be
> >> smaller
> >>>>>> than the differences you are dealing with. This might
> >> flatten out
> >> some of
> >>>>>> the bumps we're looking
> >>>>>> for. For example, your Etrue/Emeas v Emeas plot has a
> >>>>>> y-range of 0.95-1.05. I started off with this range but had
> >> a lot of
> >>>>>> empty
> >>>>>> space and therefore have changed my y-range to 0.998-1.002.
> >>>>>> Anyway, this
> >>>>>> is an update; there is
> >>>>>> still work to be done.
> >>>>>>
> >>>>>> -Chuck
> >>>>>> *************************************88
> >>>>>>
> >>>>>> -Michael
> >>>>>>
> >>>>>>
> >>>>>> On Wed, 9 Jun 2010, Sungkyun Park wrote:
> >>>>>>
> >>>>>>> Hi Michael,
> >>>>>>>
> >>>>>>> My understanding is that we do not worry about the problem
> >> of the
> >>>>>> tagger sag in FROST data.
> >>>>>>> When we make the cooking file, that problem is corrected.
> >>>>>>>
> >>>>>>> I make a same plot made at g8b.
> >>>>>>> The first plot is about E-id vs E{true photon beam} -
> >> E{measured>> >> photon beam}
> >>>>>>> The second plot is about E{measured photon beam} vs E{true
> >> photon>> >> beam} - E{measured photon beam}
> >>>>>>>
> >>>>>>> These plots are made in topology #gamma p -> p #pi+ #pi- (all
> >>>>>> detected) and the updated eloss correction is applied.
> >>>>>>> E{measured photon beam} is the initial photon energy.
> >>>>>>> E{true photon beam} is the photon energy after kinematic
> >> fitting.I used 0.05 as the confidence level cut. I used only a run
> >> 55570>> >> in period 3. The electron beam energy of period 3 is
> >> 1.645 GeV. So
> >> The energy range of E{measured photon beam} is from 0.33 GeV to
> 1.56>> GeV.
> >>>>>>> When we compare plots in CLAS-NOTE with plots attached with
> >> this>> >> email, FROST data do not have any problem of the
> tagger sag.
> >>>>>>>
> >>>>>>> Sung
> >>>>>>> Florida State University
> >>>>>>>
> >>>>>>>
> >>>>>>> ----- Original Message -----
> >>>>>>> From: Michael Dugger <dugger at jlab.org>
> >>>>>>> Date: Wednesday, June 9, 2010 1:04
> >>>>>>> Subject: [Frost] tagger sag
> >>>>>>> To: frost at jlab.org
> >>>>>>>
> >>>>>>>>
> >>>>>>>> Hi,
> >>>>>>>>
> >>>>>>>> I know that the study Sungkyun performed was to help
> >> verify the
> >> eloss
> >>>>>>>> momentum corrections, and I think that this is a reasonable
> >>>> way to
> >>>>>>>> look at
> >>>>>>>> his study. However, this sort of study is also very useful in
> >> determining
> >>>>>>>> the tagger sag. Since the eloss correction is not as
> >>>> pronounced for
> >>>>>>>> the
> >>>>>>>> Carbon and CH2 targets, these targets can give us a good
> >>>> picture on
> >>>>>>>> the
> >>>>>>>> tagger sag situation.
> >>>>>>>>
> >>>>>>>> If you look at the CLAS note:
> >>>>>>>> http://www1.jlab.org/ul/Physics/Hall-B/clas/public/2009-
> >> 030.pdf>> >> >>
> >>>>>>>> Fig. 5 on page 6 shows the tagger sag correction to be on the
> >>>> order>> >> of
> >>>>>>>> 0.5% for g1c data. For g8b data, the sag correction was
> >>>> between 0.2
> >>>>>>>> to
> >>>>>>>> 1.0% (Fig. 6 page 7). This means that we need to look for
> >> energyeffects
> >>>>>>>> on the order of 0.1% to be sure that the tagger sag is not an
> >>>>>> issue.>>
> >>>>>>>> For g8b it was found that the tagger sag correction was
> >>>> important>> >> in
> >>>>>>>> obtaining reasonable pulls for the FSU kinematic fitter (see
> >>>> table>> >> 1 on
> >>>>>>>> page 7).
> >>>>>>>>
> >>>>>>>> One way to get a better look at the energy study is to use:
> >> [E_calculated - E_measured]/E_measured
> >>>>>>>> instead of
> >>>>>>>> E_calculated/E_measured.
> >>>>>>>>
> >>>>>>>> Since Mike Williams used this sort of parametrization for g1c
> >>>> (and>> >> I
> >>>>>>>> did the same for g8b), we can more easily compare results
> >>>> between>> >> the
> >>>>>>>> different run periods to see if the shape of the energy
> >>>> correction>> >> distributions look similar. The tagger sag has a
> >> "signature" three
> >>>>>>>> bump
> >>>>>>>> pattern that should be clearly visible once we get to the
> >> 0.1%>> >> level.>>
> >>>>>>>> -Michael
> >>>>>>>> _______________________________________________
> >>>>>>>> Frost mailing list
> >>>>>>>> Frost at jlab.org
> >>>>>>>> https://mailman.jlab.org/mailman/listinfo/frost
> >>>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>
> >>>
> >>
> >>
> >>
> >>
> >>
> >
>
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