MT_MET(e-) vs MT(e- met)

Bug #1782140 reported by Michael Baker
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
MadAnalysis 5
High
Unassigned

Bug Description

Hi,

In Madanalysis 1.6, should I expect a difference between

plot MT_MET(e-)

and

plot MT(e- met)

? My reading of https://answers.launchpad.net/madanalysis5/+question/271286 suggests they should be the same, but they do not give the same plot for me.

Many thanks,

Michael

Revision history for this message
Benjamin Fuks (fuks) wrote :

Hi Michael,

We are on this. Please be patient.

Cheers,

B>

Benjamin Fuks (fuks)
Changed in madanalysis5:
status: New → In Progress
importance: Undecided → High
Revision history for this message
Eric Conte (eric-conte) wrote :

Hi Michael,

In fact, your two command lines use two different formula.

1. For the plot "plot MT(e- met)", we made the vector sum of the 4-momenta and we use the definition:
Mt^2 = E^2 - pz^2 = m^2 + px^2 + py^2 [PDG2018, (47.39)]

2. For the plot "plot MT_MT(e-), we use the formula:
MT^2 = (sum ET^2) - (sum PT^2) [PDG2018, (47.50)]

For system with MET, only the second command line is correct. The first command line gives you a wrong definition of the MT. We will add a warning message for warn people if they use the first command line.

Cheers,
Eric

Revision history for this message
Michael Baker (michaelbaker) wrote :

Hi Eric,

Great, thanks for clearing that up!

Best,

Mike

Benjamin Fuks (fuks)
Changed in madanalysis5:
status: In Progress → Fix Committed
milestone: none → v1.7
Benjamin Fuks (fuks)
Changed in madanalysis5:
status: Fix Committed → Fix Released
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