How to plot signal invariant mass plot in reconstruction mode?

Hi Kihong

By definition, reco mode accesses only reconstructed final state objects. Hence if you want to, say reconstruct a mediator’s four-vector, you are expected to setup a good selection strategy to end up with the final state particles that you want to see in your sample. If you like to have a comparisson type of analysis where you want to compare say reconstructed mass of y1 with its true mass, I suggest using LHE files without reconstruction and with [interstate] option e.g.

define y1 = < PDGID>
plot M (y1[1]) 0 50 1000 [interstate]

this will plot the “onshell” mass of y1. Note that I’m emphasizing “onshell” here because depending on your breit-weigner cut in mg5, some of your y1’s might be off-shell and not written in LHE file.

In reco mode, assuming that the decay products of y1 are expected to be most energetic FS, the simplest thing that you can do is

plot vM (l[1] l[2]) …

this will first combine the four vector of two leading leptons (I assumed that you are looking leptons in FS, it can be anything) and then plot the invariant mass of this combined 4-vector.

If you want to apply a parton-matching type of analysis in reco mode, you need to use expert mode.

cheers

—
Jack Y. Araz

> On Apr 24, 2021, at 2:45 PM, Kihong Park <email address hidden> wrote:
>
> [EXTERNAL EMAIL]
>
> Question #696738 on MadAnalysis 5 changed:
> https://answers.launchpad.net/madanalysis5/+question/696738
>
> Description changed to:
> Hello,
>
> I am stuck with reconsctruion mode analysis using MadAnalysis.
>
> My goal is to generate signal invariant mass plot using reconstruction mode using Delphes.
> To be more specific, I want to plot invariant mass of muon pair which are daughter particles of the specific mother particle.
> In my case, the mother particle is the dark photon (y1) of the 'simplified model' which is the BSM and it is used when generating events with MadGraph5.
>
> My question is, if MadAnalysis has the function to plot the Invariant mass of the daughter particles of a particular particle in the BSM model in reconstruction mode, please let me know that command.
> If not, could you please let me know the alternative methods?
>
> Thank you in advance.
>
> Kihong Park
>
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