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[CLOSED] Delta from Krivoruchenko [message #12703] Fri, 07 October 2011 10:47 Go to next message
Ingo Froehlich is currently offline  Ingo Froehlich
Messages: 167
Registered: March 2004
Location: IKF - Frankfurt
first-grade participant
From: *dip.t-dialin.net
Dear all,

please update to v5.38.2. In the previous version, the Krivoruchenko model was not enabled by using the following command:

makeDistributionManager()->Exec("dalitz_mod: krivoruchenko");

It is very important to check the output of the reaction, it should print:

[D+_krivoruchenko] dgdm from Krivoruchenko {/}

some more word to the calculation of branching ratios. By default, Pluto does not calculate the branching ratio, but takes as a weight 1/N_ev * BR, where BR is the static branching ratio. This leads of course to incorrect results at the pole, if the branching ratio shows a large mass-dependency.

The only way to let Pluto calculate the branching ratio, is the "Monte-Carlo-Integration method". In this case one has to use a flat dilepton mass generator:

makeDistributionManager()->Exec("dalitz_mod: static_br_thresh=0.100 ; flat_generator");

By using this, the another model is added:

[D+_generator_p_dilepton] Dilepton generator {/generator}

I attached below a macro which uses this method.

Toggle Spoiler


The result is shown below:

index.php?t=getfile&id=6656&private=0

and this is the branching ratio which I obtain:

index.php?t=getfile&id=6657&private=0


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--
Ingo Froehlich
IKF - University of Frankfurt
069-798-47027, FAX: -47024

[Updated on: Wed, 22 May 2013 12:37]

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Re: Delta from Krivoruchenko [message #12708 is a reply to message #12703] Tue, 11 October 2011 13:51 Go to previous messageGo to next message
Adrian Dybczak is currently offline  Adrian Dybczak
Messages: 8
Registered: January 2007
Location: Cracow Poland
occasional visitor
From: *if.uj.edu.pl
As we can see BR ratio in the pole is OK.
Also dGamma/dM is working fine.


I put distributions of Delta mass drawed for 1mln generated events directly from this macro (not in Log Scale).

index.php?t=getfile&id=6670&private=0

This looks nice.


But for mas of (proton e+ e-) one can see

index.php?t=getfile&id=6666&private=0

Question is: How large should be statistic to get smooth shape of Dalta tail? Because 1 mln is not enough as we can see.

By the way i thought that main goal to use flat gen was to make tail smoother. Do we have reversed result?






e+e- invariant mass looks quite smoothly.

index.php?t=getfile&id=6665&private=0
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  • Attachment: D_mass.png
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[Updated on: Tue, 11 October 2011 17:17]

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Re: Delta from Krivoruchenko [message #12711 is a reply to message #12708] Tue, 11 October 2011 18:28 Go to previous messageGo to next message
Ingo Froehlich is currently offline  Ingo Froehlich
Messages: 167
Registered: March 2004
Location: IKF - Frankfurt
first-grade participant
From: *dip.t-dialin.net
Dear Adrian,

thank you for this observation. I understand now much clearer what you mean when talking about fluctuations.

I think they source of the fluctuation is as follows: the pure Delta does not have the large tails. When you use the intrinsic calculation of the branching ratio (this is what we do when you want to have the correct b.r. at pole), I have to disable the explicit mass-dependent partial decay width, i.e. the tail at large masses is also disabled.

This means we strongly enhance the remaining tails. You can see this also in my plot, where I have plotted the mass-dependent branching ratio. So it is not a matter of statistics.

The only way to avoid this is to go back to the "classical" method (no flat di-electron generator). But in this case, as you know, the weight is fixed to 1/N_ev * "static branching ratio". This means you have to correct the old histogram such that it overlays with the new one, than you have a correction factor.

If I think more about it, there could be one solution, this is a "box-like" Delta generator together with the weight of the shape. But I never tested this and it is one additional source of complication.







--
Ingo Froehlich
IKF - University of Frankfurt
069-798-47027, FAX: -47024
Re: Delta from Krivoruchenko [message #12712 is a reply to message #12711] Wed, 12 October 2011 18:46 Go to previous messageGo to next message
Adrian Dybczak is currently offline  Adrian Dybczak
Messages: 8
Registered: January 2007
Location: Cracow Poland
occasional visitor
From: *if.uj.edu.pl
Hi Ingo

I have discussed with Piotr and conclusion is that fluctuations are acceptable if correction of this means lot of work. One can plot M_inv_pepem with smaller number of bins. This is not problem.
Re: Delta from Krivoruchenko [message #12726 is a reply to message #12712] Wed, 19 October 2011 10:54 Go to previous messageGo to next message
Piotr Salabura is currently offline  Piotr Salabura
Messages: 220
Registered: June 2004
Location: Institute of Physics Jagi...
first-grade participant
From: *if.uj.edu.pl
Here I post document written by Beatrice which summarize differences in descriptions of Delta Dalitz decays by various models which exist on the market. In _Pluto we use Krivoruchenko/Martemayenov which is eq. to Zetenyi/Wolf (if use constant form-factors)

Piotr


Salabura Piotr
Institute of Physics
Jagiellonian University
salabura@if.uj.edu.pl
Re: Delta from Krivoruchenko [message #12738 is a reply to message #12703] Thu, 20 October 2011 09:17 Go to previous messageGo to next message
Malgorzata Gumberidze is currently offline  Malgorzata Gumberidze
Messages: 98
Registered: June 2005
continuous participant
From: *gsi.de
I have made similar studies for the pp@2.2.

For the pluto cocktail which is included into the
draft of the publication we were using pluto version v5.36
and PDecayManager. In the plot below you can see mass
dependent branching ratio for the Delta+ in channel
pp->pD+.

the color meaning is following:

Pluto v5_36 with DecayManager, not working Krivoruchenko, no flat generator

PLEASE notice that there is mistake in the label in plot, it is v5.36 and not v5.26


Pluto v5_38.2 with PReaction and all flags switch on:

makeDistributionManager()->Exec("elementary");
makeDistributionManager()->Exec("dalitz_mod: krivoruchenko");
makeDistributionManager()->Exec("dalitz_mod:static_br_thresh=0.100 ; flat_generator");


In case of the BLACK normalization comes for free using weights. RED curve is normalize in a way that at pole this ration is 4.15e-5.

index.php?t=getfile&id=6703&private=0


mass dependance of the BR in both calculations are very similar.
That means if the DecayManager spectra are scaled such that average BR is 5.9e-5 (as obtain with the recommnded procedure from the Forum) then the resulting Delta contribution to the dilepton mass spectrum should be fine.

same investigation for the rho0 will follow

gosia


[Updated on: Thu, 20 October 2011 10:29]

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rho BR [message #12741 is a reply to message #12738] Thu, 20 October 2011 10:27 Go to previous messageGo to next message
Malgorzata Gumberidze is currently offline  Malgorzata Gumberidze
Messages: 98
Registered: June 2005
continuous participant
From: *gsi.de
Please find here now plot which is showing mass dependent BR for the rho0.

In similar way as before:

For the pluto cocktail which is included into the
draft of the publication we were using pluto version v5.37
and PDecayManager. This version is different then for Delta
but it is due to some futures in case of rho0 which were in previous version, and were not correct.

In the plot below you can see mass
dependent branching ratio for the Delta+ in channel
pp->pprho0.

In case of the BLACK normalization comes for free using weights. RED curve is normalize in a
way that at pole BR is the same like for BLACK one.

index.php?t=getfile&id=6704&private=0

Please notice also that in this case the BR at pole is not
correct, but maybe i do something wrong, so please ingo have
a look into my macro.

gosia

Re: Delta from Krivoruchenko [message #12743 is a reply to message #12703] Mon, 24 October 2011 11:22 Go to previous messageGo to next message
Tetyana Galatyuk is currently offline  Tetyana Galatyuk
Messages: 106
Registered: July 2004
Location: GSI, Darmstadt
continuous participant
From: *gsi.de
Dear all,

to complete the story, I have prepared
few plots for p+p at Ekin=1.25 GeV.

Figure bellow shows the mass dependent
branching ratio of Delta estimated by dividing
pp->pDelta+->pppi0 by pp->pDelta+->ppe+e-

index.php?t=getfile&id=6707&private=0


The next point which was checked concerns the following issue:
Ingo wrote:
>please update to v5.38.2. In the previous version,
>the Krivoruchenko model was not enabled by using
>the following command:
>makeDistributionManager()->Exec("dalitz_mod: krivoruchenko");


Bellow you can find a figure which shows the
Delta+ mass distribution in channel pp->pD+->ppe+e-
for two versions of Pluto. Indeed, the Krivoruchenko
model was not enable in the Pluto versions < v5.38.2!
index.php?t=getfile&id=6708&private=0

Finally, you can see the influence on invariant
e+e- mass spectrum:
index.php?t=getfile&id=6711&private=0

[Updated on: Mon, 24 October 2011 17:37]

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Re: Delta from Krivoruchenko [message #12750 is a reply to message #12743] Tue, 25 October 2011 19:59 Go to previous message
Anar Rustamov is currently offline  Anar Rustamov
Messages: 136
Registered: June 2005
Location: GSI
first-grade participant
From: *dip.t-dialin.net
There is also Delta and Rho Branching ratios from my simulation.
Note:
I use PYTHIA output both for the Delta and Rho.
Then I decay Delta inside PLUTO, while Rho I decay myself within VMD;

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  • Attachment: rhoMass.png
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  • Attachment: RhoBr.png
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