Mother/Daughter Particles

[avikar]

Hi,

I was wondering about the mother/daughter particles in the particle branch. I made sure my Delphes card had
add Branch Delphes/allParticles Particle GenParticle
as mentioned in some previous tickets.
I printed out the first few particles in the particle branch (which had only 338 members), and I noticed a few things.

1. There are many of referenced particles that are above the the number of entries in the particle branch (all the numbers > 337).
2. Mothers and daughters are not consistent. For example, particles 7 + 8 both have particles 9 + 10 as daughters, yet particles 9 + 10 reference particles 5 + 6 respectively as their mothers. Similarly particle 13 lists particle 18 as a mother, yet particle 5 lists particle 13 as the daughter.

  	M1 	M2 	D1 	D2
0 	0 	0 	0 	0
1 	0 	0 	723 	0
2 	0 	0 	724 	0
3 	11 	0 	5 	6
4 	12 	12 	5 	6
5 	3 	4 	13 	13
6 	3 	4 	14 	14
7 	34 	34 	9 	10
8 	35 	0 	9 	10
9 	5 	5 	18 	18
10 	6 	6 	19 	19
11 	13 	13 	64 	64
12 	14 	14 	65 	65
13 	18 	18 	725 	725
14 	19 	19 	726 	726
15 	64 	64 	951 	952
16 	65 	65 	992 	993
17 	725 	0 	953 	954
18 	725 	0 	955 	955 

I've attached my card to this ticket, in case I'm making mistakes there.

Thanks very much!

[avikar]

Delphes Card

[Michele Selvaggi]

Hi,

could you please provide a small input file that produces this behaviour?

Michele

[avikar]

The root output file is here: ​https://www.dropbox.com/s/oatutxclh7r4wae/higgs_out2.root?dl=0, and the input promc file (I used DelphesProMC) is here: ​https://www.dropbox.com/s/4vr1dlagwio33l3/pythia8_higgs_1.promc?dl=0

Thanks!

[Pavel Demin]

Thanks for all the files. I've just build DelphesProMC with ProMC 1.6 and tried to run the following command:

./DelphesProMC cms_notau.tcl pythia8_higgs_1.root pythia8_higgs_1.promc

I've obtained the same inconsistent mother/daughter indices as in your first comment.

However, Delphes doesn't calculate the mother/daughter indices it obtains them from the ProMC library. You can find the code that gets the mother/daughter indices on lines 127-131 in readers/DelphesProMC.cpp:

https://cp3.irmp.ucl.ac.be/projects/delphes/browser/git/readers/DelphesProMC.cpp#L127

So, I'd say that something is wrong with the pythia8_higgs_1.promc file.