Using Fastjet in Pythia to plot distribution of particles

[Sandeep Hundal]

I am using fastjet in pythia8.I am studying jet formation in pp collisions.I need to plot distribution of transverse momentum of fastest particle in fastest jet formed in 1000 events simulated.But i don't know how to access particle properties after jet formation.Like if I want to know the fastest particle out of the particles which have formed that jet ,I am not able to access it.Can anybdy explain ?
Thanks

 

[mfb]

The fastest particle? That is an unusual quantity.

The quickstart has an example how to access the jet constituents.

 

[ChrisVer]

by fastest you mean the one with the highest pt? (would make more sense at least from my experience)

 

[Sandeep Hundal]

yes ,here fastest means with highest pt

 

[Sandeep Hundal]

The fastest particle? That is an unusual quantity.

The quickstart has an example how to access the jet constituents.

It worked
Thanks

 

[Sandeep Hundal]

How can we access lowest pt particle(constituent) of sub leading jet ?

 

[Vanadium 50]

Does Section 3.5 of the manual not cover that?

 

[mfb]

The functions shown in the quickstart example are sufficient for this as well.

 

[Sandeep Hundal]

yes,It worked now.Actually in some of the events,only less than 2 jets were formed.so It gave an error.Now I have imposed the condition to select only those events that have more than 1 jet.Now the question is -is that possible that in some events no jet formed even after clustering in pythia using fastjet?
Thanks .Your guidance is helping me a lot :)

 

[mfb]

It depends on the events simulated, but in general: sure. Not every pp collision produces particles high-energetic enough to be included in jets. Some don't produce particles in the detector at all.

 

[ChrisVer]

Now the question is -is that possible that in some events no jet formed even after clustering in pythia using fastjet?

Hmmm, I would like to know what you define as a jet? Would a muon give you a jet?
As jets I was imagining objects of grouped clusters (which are grouped cells), that satisfy certain quality criteria (some energy thresholds and so on). Those are formed only for signals recorded in the calorimeter (so objects that are recoed from the calorimeter won't be called jets?).
Then are you referring to the jets that come from the hard scattering process?

 

[Sandeep Hundal]

yes,I am referring to the jets that come from hard scattering processes after fragmentation and hadronization.

 

[ChrisVer]

So ignoring the pileup jets, the process: $qq\to W \to \mu \nu$ wouldn't necessarily give you a "jet" in your event.