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Dalitz Decays of higher resonances. [message #12713]

Wed, 12 October 2011 18:54

Adrian Dybczak
Messages: 8
Registered: January 2007
Location: Cracow Poland

occasional visitor

From: *if.uj.edu.pl

Dear Ingo

I tried to simulate Dalitz decay of higher resonances. I used macros prepared (mixed) by my self.
One can find it in attachment.
In this topic i propose to focus on one resonance N1520+ which is example.

After several tests i redeclared N1535 resonance in macro without using names from pluto. This was only way to get "proper" result.
Names in macro

AddAlias("N1520+","N_star(1520)+");

Names in PLUTO

AddAlias("ND13+","N*(1520)+");

So there is no conflict.

What i wanted to check was:
1/. BR value for Dalitz Decay
2/. is dGamma/dM (Zetenyi/Wolf model) working.

Ad 1/. I drawed M_inv_pee from pp->pN1520->ppe+e- reaction

index.php?t=getfile&id=6672&private=0

Then i drawed invariant mass of npi+ from pp->pN1520->pnpi+ reaction.

index.php?t=getfile&id=6673&private=0

BR_NPi = 0.55 ; Clebsch_Gordan coeff. = 2/3.

so 4.048e-2/(0.55*0.66) = 0.11

now getting 5.36e-6/0.11 = 4.8e-5

What was assumed in macro as 5.0e-5

Ad 2/. dGamma/dM was only check via looking on display hile processing and various value of weight.

By the way below one can find distribution of weight.

index.php?t=getfile&id=6674&private=0

It looks slightly different from D1232 weight distribution.

Ingo could you check this macro or provide new one which can be uses to simulate Dalitz Decay for N1520+ without any redelaration?

Attachment: reaction.C
(Size: 5.82KB, Downloaded 439 times)
Attachment: m_inv_pee.png
(Size: 10.16KB, Downloaded 825 times)
Attachment: m_inv_npip.png
(Size: 11.65KB, Downloaded 902 times)
Attachment: weight.png
(Size: 10.24KB, Downloaded 928 times)

[Updated on: Wed, 12 October 2011 20:16]

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Re: Dalitz Decays of higher resonances. [message #12714 is a reply to message #12713]

Thu, 13 October 2011 07:52

Ingo Froehlich
Messages: 167
Registered: March 2004
Location: IKF - Frankfurt

first-grade participant

From: *dip.t-dialin.net

Adrian Dybczak wrote on Wed, 12 October 2011 18:54

After several tests i redeclared N1535 resonance in macro without using names from pluto. This was only way to get "proper" result.

What was wrong with the build-in version in "dalitz_mod"? It would be important for me to know this.

Adrian Dybczak wrote on Wed, 12 October 2011 18:54

now getting 5.36e-6/0.11 = 4.8e-5
What was assumed in macro as 5.0e-5

Remember: What you declare in Pluto is the static branching ratio. What you see in the histogram is the weight directly coming from the model (basically the coupling constant), this we can see here:

my_reaction->Do("_w = _w * {N1520+_dalitz}->GetBR([N1520+]->M());");

what is done here is to fold the weight with the mass-dependent branching ratio. This was (originally) implemented to feed the Pythia rho into Pluto in order to change the shape.

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

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Re: Dalitz Decays of higher resonances. [message #12715 is a reply to message #12714]

Thu, 13 October 2011 16:26

Adrian Dybczak
Messages: 8
Registered: January 2007
Location: Cracow Poland

occasional visitor

From: *if.uj.edu.pl

Hi Ingo

In the same way as previosly i made several test.
I used same macro as you send me to simulate D+ but this time ND13+ (N*1520) was simulated (macro in attachment).
Here are results:

Mass of Delta
index.php?t=getfile&id=6675&private=0

Mass of pee
index.php?t=getfile&id=6676&private=0

Ratio means BR

index.php?t=getfile&id=6677&private=0

One can see that:
- shapes are ok
- BR ratio in pole is same as expected (0.0051/137=3.7e-5)

Commend

[ND13+_dalitz] dgdm from Zetenyi/Wolf {/}

is displayed while processing but weight is constant

index.php?t=getfile&id=6678&private=0

Does it means that dGamma/dM working or not?

Attachment: mass_Delta.png
(Size: 8.90KB, Downloaded 520 times)
Attachment: mass_pee.png
(Size: 8.74KB, Downloaded 507 times)
Attachment: ratio.png
(Size: 9.24KB, Downloaded 461 times)
Attachment: weight.png
(Size: 9.31KB, Downloaded 511 times)
Attachment: test_elementary_adrian.C
(Size: 1.93KB, Downloaded 275 times)

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Re: Dalitz Decays of higher resonances. [message #12716 is a reply to message #12715]

Thu, 13 October 2011 17:36

Ingo Froehlich
Messages: 167
Registered: March 2004
Location: IKF - Frankfurt

first-grade participant

From: *x-matter.uni-frankfurt.de

You are absolutely right, there was no flat electron generator enabled. The reason is that the new decays were not recognized as Dalitz-Decays (hardcoded in PData.h).

I did the following changes in PData.h (IsDalitz):

      int d = makeStaticData()->GetParticleBaryon(id) &&  // Delta0 Dalitz decay?
	  ((makeStaticData()->IsParticle(i1,"dilepton") && 
	    makeStaticData()->GetParticleBaryon(i2)) || 
	   (makeStaticData()->GetParticleBaryon(i1) && 
	    makeStaticData()->IsParticle(i2,"dilepton")));

      return (pseudo&&eeg) || (pseudo&&mumug) || 
	  (vector&&eepi) || (vector&&mumupi)
	  || D0 || Dp || pn || NS0 || NSp || d;

now it should print:

Info in <PDalitzModPlugin::ExecCommand>: Model <NS11+_dalitz> uses dGamma/dM for the branching ratio
Info in <PDalitzModPlugin::ExecCommand>: Model <NP110_dalitz> uses dGamma/dM for the branching ratio
Info in <PDalitzModPlugin::ExecCommand>: Model <ND130_dalitz> uses dGamma/dM for the branching ratio
Info in <PDalitzModPlugin::ExecCommand>: Model <NS110_dalitz> uses dGamma/dM for the branching ratio

and:

[ND13+_generator_p_dilepton] Dilepton generator {/generator}

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

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Re: Dalitz Decays of higher resonances. [message #12717 is a reply to message #12716]

Thu, 13 October 2011 21:24

Adrian Dybczak
Messages: 8
Registered: January 2007
Location: Cracow Poland

occasional visitor

From: *if.uj.edu.pl

So i apply changes and it works!

Please see pictures below.
index.php?t=getfile&id=6680&private=0

All comments were displayed hile processing.
Weight is changing (see below).

index.php?t=getfile&id=6682&private=0

Now BR is 5e-5 in pole. Shouldn`t be 3.7-5 as before?

Attachment: mass_comparison.png
(Size: 11.02KB, Downloaded 505 times)
Attachment: ratio.png
(Size: 9.25KB, Downloaded 508 times)
Attachment: weight.png
(Size: 11.65KB, Downloaded 516 times)

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Re: Dalitz Decays of higher resonances. [message #12718 is a reply to message #12717]

Thu, 13 October 2011 22:50

Ingo Froehlich
Messages: 167
Registered: March 2004
Location: IKF - Frankfurt

first-grade participant

From: *dip.t-dialin.net

Adrian Dybczak wrote on Thu, 13 October 2011 21:24

Now BR is 5e-5 in pole. Shouldn`t be 3.7-5 as before?

Hard to say. It directly comes from the model (i.e. the coupling constant). Maybe we have to check it against a calculation using the equations from the paper

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

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