MadGraph5_aMC@NLO

Madgraph fails to produce specified number of events and madanalysis cards

Asked by Shubhani Jain

Hi

I have been trying to get some events for bg > tw h process. I am using 2hdmtII_nlo model for the generation and then defining some multiparticles:

MG5_aMC>import model 2HDMtII_NLO
INFO: Change particles name to pass to MG5 convention
Kept definitions of multiparticles p / j / l+ / l- / vl / vl~ unchanged
Defined multiparticle all = g ghg ghg~ u c d s u~ c~ d~ s~ a gha gha~ ve vm vt e- mu- ta- ve~ vm~ vt~ e+ mu+ ta+ t b t~ b~ z w+ ghz ghwp ghwm h+ h1 h2 h3 w- ghz~ ghwp~ ghwm~ h-
MG5_aMC>define ws = w+ w-
Defined multiparticle ws = w+ w-
MG5_aMC>define ts = t t~
Defined multiparticle ts = t t~
MG5_aMC>define nu = ve vm ve~ vm
Defined multiparticle nu = ve vm ve~
MG5_aMC>define bs = b b~
Defined multiparticle bs = b b~
MG5_aMC>define l = e+ mu+ e- mu-
Defined multiparticle l = e- mu- e+ mu+
MG5_aMC>generate bs g > ts ws h1 , ( ts > bs ws , ws > l nu ) , ( ws > j j ) , ( h1 > z z , z > l+ l- , z > l+ l- )

I am specifying the number of events to be 10k but only get 5580 events, not sure what is going wrong there.

Another thing is madanalysis fails to generate both parton level and hadron level cards:
WARNING: MadAnalysis5 failed to write a parton-level default analysis card for this process.
WARNING: Therefore, parton-level default analysis with MadAnalysis5 will be empty.
WARNING: MadAnalysis5 failed to write a hadron-level default analysis card for this process.
WARNING: Therefore, hadron-level default analysis with MadAnalysis5 will be empty.

I used to get aleast parton level card before, but now even that is not being done. I am using 3.3.1 version.

Regards
Shubhani

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Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

What is the mass of h1 and the mass of Z in your model.

If those are at SM value, then the process that you ask for does not make sense (you ask an onshell h1 to decay to two onshell Z)
and then this is likely the main reason why you fail to reach your number of event (but more importantly the distribution will be wrong).

Assuming SM value, that process has actually two contribution, one where the h1 is onshell and one were the two Z are onshell.
So which one of the two do you want?

Olivier

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Shubhani Jain (s2697661) said : 		#2

Hi Olivier

I am using:
23 9.118760e+01 # MZ
25 1.250000e+02 # mh1

I want h1 to be on-shell as I just want to decay h1 >z z. Would it be better to have these decay chain mad spin with mad spin mode none?

Also what could be the reason behind mad analysis not producing the parton level and hardon level cards?

Thanks
Shubhani

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Olivier Mattelaer (olivier-mattelaer) said : 		#3

so if you want the have h1 onshell and (technically one) the Z offshell, then you should use the syntax:

generate bs g > ts ws h1 , ( ts > bs ws , ws > l nu ) , ws > j j , h1 > z > l+ l- l+ l-

For MA5, the reason is likely that it fails to understand your process definition.
Your process definition is certainly not the simplest one to handle since you do have a lot of decays in sequence and a lot of multi-particle involved and ambiguous decay (two W decaying differently at two different part of your decay).

For this reason MA5 is unable to provide a default card for that process.

Maybe one work-around is to avoid the usage of multi-particles like ws, bs ts
and use "add process" for those? But as I'm not an author of MA5, I can not really comment on that.

Cheers,

Olivier

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Shubhani Jain (s2697661) said : 		#4

Hi Olivier

Thanks for this.

I can actually try to not use so many multi-particle definitions. I did found a small mistake in my definition of nu where I was missing vm~ after correcting that ma5 does give me parton level card but not hadron level one. For add process syntax:

generate b g > t ws h1 , (t > w+ b , w+ > l+ vl), (ws > j j ), h1 > z > l+ l- l+ l-
add process b~ g > t~ ws h1 , (t~ > w- b~ , w- > l- vl~), (ws > j j ), h1 > z > l+ l- l+ l-

would this be correct or there will be a repetition of diagrams?

Regards
Shubhani

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Olivier Mattelaer (olivier-mattelaer) said : 		#5

Since your initial state is different, you can not have double counting.

Cheers,

Olivier

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Shubhani Jain (s2697661) said : 		#6

Thanks, I think I will stick with not using multiple multi-particle definition and use the above mentioned syntax.

Regards
Shubhani