[Frost] tagger sag
Sungkyun Park
sp06k at fsu.edu
Wed Jun 16 16:53:41 EDT 2010
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
* θ 1 - 7, 10 degrees each bin
* π 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
* θ 1 - 14, 10 degrees each bin
* π 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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