WARNING: Decay MadGraph: without corresponding particle in core process found.

Hi,

You want to do:
generate p p > ZD, (ZD > FD1 FD1, (FD1 > FD2 gammaD, gammaD > mu+ mu-))

All the others example are technically not valid for your syntax since the above syntax assumes that the particles is onshell.
So you can not decay a particle to themself (at least one of the two will be off-shell)

Cheers,

Olivier

Thank you for your response, Oliver!

I'm still having a hard time generating events.

When I try:

generate p p > gammaD, (gammaD > FD1 FD1, (FD1 > FD2 gammaD, gammaD > mu+ mu-))

or:

generate p p > ZD, (ZD > FD1 FD1, (FD1 > FD2 ZD, ZD > mu+ mu-))

I get this error:

Zero result detected: No Phase Space. Please check particle masses.

Can you tell me what the problem is here?

--------------------------------------------------------------------------
These are my particles:

F[7] == { ClassName -> Fd1,
          SelfConjugate -> True,
      Mass -> {MFd1, 30.},
          Width -> {WFd1,1.00000000e-05},
          PDG -> 5000521,
          TeX -> Subscript[X,d1],
          FullName -> "Dirac DM" },

F[8] == { ClassName -> Fd2,
          SelfConjugate -> True,
      Mass -> {MFd2, 4.},
          Width -> 0,
          PDG -> 5000522,
          TeX -> Subscript[X,d2],
          FullName -> "Dirac DM" },

V[7] == { ClassName -> gammaD,
      SelfConjugate -> True,
      Mass -> {MgammaD, 10.},
          Width -> {WgammaD, 1.00000000e-05},
          PDG -> 5000001,
          TeX -> Subscript[gamma,D],
          FullName -> "gammaD" },

V[8] == { ClassName -> ZD,
      SelfConjugate -> True,
      Mass -> {MZD, 90.},
          Width -> {WZD, 2.},
          PDG -> 5000002,
          TeX -> Subscript[Z,D],
          FullName -> "ZD" }

};

------------------------------------------------------------------------
Thank you,

This is an impossible on shell decay. A particle cannot decay into himself

Cheers

Olivier

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________________________________
From: <email address hidden> on behalf of mehdirahmani <email address hidden>
Sent: Tuesday, April 9, 2019 4:17 PM
To: Olivier Mattelaer
Subject: Re: [Question #680128]: WARNING: Decay MadGraph: without corresponding particle in core process found.

Question #680128 on MadGraph5_aMC@NLO changed:
https://answers.launchpad.net/mg5amcnlo/+question/680128

Status: Answered => Open

mehdirahmani is still having a problem:
Thank you for your response, Oliver!

I'm still having a hard time generating events.

When I try:

generate p p > gammaD, (gammaD > FD1 FD1, (FD1 > FD2 gammaD, gammaD >
mu+ mu-))

or:

generate p p > ZD, (ZD > FD1 FD1, (FD1 > FD2 ZD, ZD > mu+ mu-))

I get this error:

Zero result detected: No Phase Space. Please check particle masses.

Can you tell me what the problem is here?

--------------------------------------------------------------------------
These are my particles:

F[7] == { ClassName -> Fd1,
SelfConjugate -> True,
Mass -> {MFd1, 30.},
Width -> {WFd1,1.00000000e-05},
PDG -> 5000521,
TeX -> Subscript[X,d1],
FullName -> "Dirac DM" },

F[8] == { ClassName -> Fd2,
SelfConjugate -> True,
Mass -> {MFd2, 4.},
Width -> 0,
PDG -> 5000522,
TeX -> Subscript[X,d2],
FullName -> "Dirac DM" },

V[7] == { ClassName -> gammaD,
SelfConjugate -> True,
Mass -> {MgammaD, 10.},
Width -> {WgammaD, 1.00000000e-05},
PDG -> 5000001,
TeX -> Subscript[gamma,D],
FullName -> "gammaD" },

V[8] == { ClassName -> ZD,
SelfConjugate -> True,
Mass -> {MZD, 90.},
Width -> {WZD, 2.},
PDG -> 5000002,
TeX -> Subscript[Z,D],
FullName -> "ZD" }

};

------------------------------------------------------------------------
Thank you,

--
You received this question notification because you are an answer
contact for MadGraph5_aMC@NLO.

Doesn't the syntax that you proposed in response #1 allow for second gammaDs to be off-shell? (which is what I tried)

If not, what syntax would ensure that one of the two gammaDs is off-shell and let my events to be generated?

Thank you,

Hi,

Instead of

A > B C , C > D E
You should ask
A > B D E
When you want C to be off she’ll

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________________________________
From: <email address hidden> on behalf of mehdirahmani <email address hidden>
Sent: Tuesday, April 9, 2019 5:08 PM
To: Olivier Mattelaer
Subject: Re: [Question #680128]: WARNING: Decay MadGraph: without corresponding particle in core process found.

Question #680128 on MadGraph5_aMC@NLO changed:
https://answers.launchpad.net/mg5amcnlo/+question/680128

Status: Answered => Open

mehdirahmani is still having a problem:
Doesn't the syntax that you proposed in response #1 allow for second
gammaDs to be off-shell? (which is what I tried)

If not, what syntax would ensure that one of the two gammaDs is off-
shell and let my events to be generated?

Thank you,

--
You received this question notification because you are an answer
contact for MadGraph5_aMC@NLO.

Hi Oliver,
Thank you for your suggestion.
I have produced some plots with below syntax, using madanalysis:

generate p p > ZD, (ZD > FD1 FD1, (FD1 > FD2 mu+ mu-)) by using madanalysis

It seems that the the FD2s are not interstate particles any more and the mu+ mu- 's mother is FD1 and not ZD. How can I ensure that the mu+ mu- s decay from ZDs?

Thank you,

correction to last message:

I have produced some events by using the below syntax in madgraph:

generate p p > ZD, (ZD > FD1 FD1, (FD1 > FD2 mu+ mu-))

when I plot them using madanalysis, It seems that the the FD2s are not interstate particles any more and the mu+ mu- 's mother is FD1 and not ZD.
How can I ensure that the mu+ mu- s decay from ZDs?

Also there is no sign of off-shell ZDs in the lhe file.

Thank you,

The mother information only contains onshell particles so the information from ma5 makes sense.
And does not mean that Xs is not present.

We have a faq on that point.

Cheers

Olivier

Olivier Mattelaer suggests this article as an answer to your question:
FAQ #2173: “Intermediate Boson missing from events in LHE output file”.