missing truth particles in WWW events

[Jenny]

I've been generating p p > w w w events in Madgraph where the w's all go to lepton+neutrino. I've showered the events in pythia (via madgraph interface) and then run Dephes 3.0.9. When I look at the Delphes output file, a few out of 10k events have only 5 leptons at parton level or only 2 bosons. The parton level lhe file in Madgraph looks correct. I've output the particle ID's for a couple example events below. I'm looking for three W's and 6 leptons with status 3:

3 W's, 5 leptons:
status: 3 PID: 21
status: 3 PID: 2
status: 3 PID: -1
status: 3 PID: 2
status: 3 PID: 24
status: 3 PID: 25
status: 3 PID: -13
status: 3 PID: 14
status: 3 PID: 24
status: 3 PID: -24
status: 3 PID: -11
status: 3 PID: 13
status: 3 PID: -14
Three W 24 24 -24, three charged leptons -13 -11 13, but only two neutrinos 14, -14. You should have a neutrino with PID 12.

Example 2, again with a missing lepton:
status: 3 PID: 2
status: 3 PID: -1
status: 3 PID: 2
status: 3 PID: -1
status: 3 PID: 24
status: 3 PID: 25
status: 3 PID: -13
status: 3 PID: 14
status: 3 PID: 24
status: 3 PID: -24
status: 3 PID: -11
status: 3 PID: 12
status: 3 PID: -14
Three W 24, 24,-24, two charged leptons -13 -11, three neutrinos 12 14 -14. You should have another charged lepton with PID 13.

Example 3, missing boson:
status: 3 PID: 21
status: 3 PID: 4
status: 3 PID: -3
status: 3 PID: 25
status: 3 PID: -11
status: 3 PID: 12
status: 3 PID: 24
status: 3 PID: -24
status: 3 PID: -13
status: 3 PID: 14
status: 3 PID: 11
status: 3 PID: -12
status: 2 PID: 25
status: 1 PID: -11
status: 1 PID: 12
status: 2 PID: 24
status: 2 PID: -24
status: 2 PID: -13
status: 2 PID: 14
status: 1 PID: 11

[Michele Selvaggi]

Hi,

let me ask you, just to be sure, do the same events have different entries in the corresponding madgraph lhe file?
Are you sure Pythia is not modifying MadGraph status 3 particles?

Michele

[Pavel Demin]

Could you, please print all the particles for one of the events in a format more or less like

Index   Status   PID    M1   M2   D1  D2
0       3        21	-1   -1   -1  -1

This will help us to understand what happens with missing particles.

[Pavel Demin]

In the detector card developed by the Snowmass group, the StatusPidFilter module is configure to filter out some of the MC truth particles.

The detector cards from the examples directory don't use the StatusPidFilter module.