[G12] GFlux

Eugene Pasyuk pasyuk at jlab.org
Fri Mar 28 16:13:28 EDT 2014 

The other thing is to make sure when you select your events and match them to the tagger you use tagger hits with status 7 or 15 only. 

-Eugene 

----- Original Message -----

> From: "Eugene Pasyuk" <pasyuk at jlab.org>
> To: "Michael C. Kunkel" <mkunkel at jlab.org>
> Cc: "g12" <g12 at jlab.org>, "Johann Goetz" <theodore.goetz at gmail.com>
> Sent: Friday, March 28, 2014 4:04:41 PM
> Subject: Re: [G12] GFlux

> The way to figure out is to look at the flux and yield and normalized
> yield per E-bin, that is the finest binning. If they are consistent,
> the the problem is in re-binning procedure. If they are not, then we
> have to look further. Technically speaking there is not unusual that
> you may have holes on photon spectrum, that would just indicate that
> some of the counters are dead.

> -Eugene

> ----- Original Message -----

> > From: "Michael C. Kunkel" <mkunkel at jlab.org>
> 
> > To: "Eugene Pasyuk" <pasyuk at jlab.org>, "Johann Goetz"
> > <theodore.goetz at gmail.com>
> 
> > Cc: "g12" <g12 at jlab.org>
> 
> > Sent: Friday, March 28, 2014 3:55:45 PM
> 
> > Subject: Re: [G12] GFlux
> 

> > Greetings,
> 

> > I am wondering where we are at with the flux issue?
> 
> > Meaning, what is going on with the flux in the 3.5 GeV region?
> 

> > I feel that the flux is in error for a few reasons.
> 
> > First when I bin flux in 15 MeV, I see 0 flux at 3.515 - 3.53.
> 
> > Second, when I bin flux in 50 MeV binning I see a drop in flux at
> > 3.5
> > MeV
> 
> > Here is the output
> 
> > //
> 
> > 3.45 3.5 1.06825209003e+12
> 
> > 3.5 3.55 470202243457.0
> 
> > 3.55 3.6 1.69234003548e+12
> 
> > //
> 

> > Third reason is that if you look at my attached pdf, I show the pi0
> > cross section for various energies, if you were to go to compare
> > the
> > cross sections around 3.5 GeV to the neighboring Egamma bins, you
> > will notice a sizable discrepancy. See G12_XSection_ALL.pdf
> 

> > Fourth reason, if I were to compare the pi0 cross section in unit
> > of
> > dsigma/dt and compare it other experiments at 4 and 5 GeV, our
> > cross
> > section is off by a factor of 2, see t_vs_dsigdt_Compare.pdf
> 

> > In order for any g12 papers to be published, we need verification
> > of
> > cross sections, which as of this moment I do not believe we have.
> 

> > BR
> 
> > MK
> 

> > On 3/25/14 10:16 PM, Eugene Pasyuk wrote:
> 

> > > This is not quite correct, especially when bins are small and
> > > comparable with the width of E-bin.
> > 
> 
> > > Just imagine, You energy bin is 3.000-3.015 GeV. E-bin let's say
> > > covers 3.0121-3.0181 GeV. The center of E-bin will be 3.01505
> > > GeV.
> > > When you enter this into the histogram it will fall to
> > > 3.015-3.030
> > > bin then. However, this E-bin should be split between two
> > > adjacent
> > > bins in new binning scheme. There are two possible ways of doing
> > > this. Either randomize energy within the width of the E-bin
> > > before
> > > you enter it to th ehistogram, or split it between adjacent bins
> > > using weight which depends on how the bin boundary splits E-bin
> > > and
> > > have two entries to the histogram with sum of the weights equal
> > > one.
> > > You can imagine, if the bin width is chosen to be less than the
> > > widths of E-bin, then you will get completely empty bins in
> > > resulting histogram.
> > 
> 

> > > -Eugene
> > 
> 

> > > ----- Original Message -----
> > 
> 

> > > > From: "Johann Goetz" <theodore.goetz at gmail.com>
> > > 
> > 
> 
> > > > To: "Eugene Pasyuk" <pasyuk at jlab.org>
> > > 
> > 
> 
> > > > Sent: Tuesday, March 25, 2014 9:12:49 PM
> > > 
> > 
> 
> > > > Subject: Re: [G12] GFlux
> > > 
> > 
> 

> > > > I consider the beam energy to be the center of the energy
> > > > paddle
> > > > and
> > > > fill the histogram at that energy with the number if counts in
> > > > the
> > > > gflux file. Is that wrong?
> > > 
> > 
> 
> > > > On Mar 25, 2014 5:59 PM, "Eugene Pasyuk" < pasyuk at jlab.org >
> > > > wrote:
> > > 
> > 
> 

> > > > > I see four numbers in each row in this file. I figured the
> > > > > first
> > > > > one
> > > > > is E-bin number. What are the other three? I guess the second
> > > > > and
> > > > > the fourth are some energies. What is the third number which
> > > > > is
> > > > > integer and varies a lot.
> > > > 
> > > 
> > 
> 
> > > > > When you say you "histogram" does it mean you take one fixed
> > > > > number
> > > > > for each E-bin (beam centroid?) and put it in the histogram,
> > > > > or
> > > > > something else?
> > > > 
> > > 
> > 
> 

> > > > > -Eugene
> > > > 
> > > 
> > 
> 

> > > > > > From: "Johann Goetz" < theodore.goetz at gmail.com >
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > To: "g12" < g12 at jlab.org >
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > Sent: Tuesday, March 25, 2014 5:40:42 PM
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > Subject: Re: [G12] GFlux
> > > > > 
> > > > 
> > > 
> > 
> 

> > > > > > The output of gflux includes a file that has the energies
> > > > > > of
> > > > > > the
> > > > > > individual energy paddles and the counts. These files are
> > > > > > then
> > > > > > used
> > > > > > to fill a histogram in the g12-gflux script where the range
> > > > > > and
> > > > > > bins
> > > > > > are specified on the command line. The energies are
> > > > > > slightly
> > > > > > "corrected" to the ones found in the following file:
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > /group/clas/parms/pcor/g12/tagger_energies.dat
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > But, the correction is very small and averaged over the
> > > > > > whole
> > > > > > run
> > > > > > period (i.e. not one a run-by-run basis).
> > > > > 
> > > > 
> > > 
> > 
> 

> > > > > > And before you ask, the the summing of the flux is valid to
> > > > > > at
> > > > > > least
> > > > > > 4 figures - probably 5.
> > > > > 
> > > > 
> > > 
> > 
> 

> > > > > > -- Johann
> > > > > 
> > > > 
> > > 
> > 
> 

> > > > > > On Tue, Mar 25, 2014 at 4:28 PM, Michael C. Kunkel <
> > > > > > mkunkel at jlab.org
> > > > > > > wrote:
> > > > > 
> > > > 
> > > 
> > 
> 

> > > > > > > Greetings,
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 

> > > > > > > If the data shows a hole at beam energies, how does the
> > > > > > > gflux
> > > > > > > for
> > > > > > > this
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > > energy have events?
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > > Below is a table of Gflux for 15MeV binning, which is to
> > > > > > > fine
> > > > > > > for
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > > analysis but great for illustrating this question.
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 

> > > > > > > Also, notice the 0 entries at 3.5 GeV, and low events in
> > > > > > > neighbors.
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > > FORMAT: Emin:Emax:Flux
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 

> > > > > > > _______________________________________________
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 
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> > > > 
> > > 
> > 
> 
> > > > > > > G12 at jlab.org
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 
> > > > > > > https://mailman.jlab.org/mailman/listinfo/g12
> > > > > > 
> > > > > 
> > > > 
> > > 
> > 
> 

> > > > > > _______________________________________________
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> 
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> > > 
> > 
> 

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> > 
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