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JetUserperspective

User perspectives on "Jet documentation"

I've found a rather comprehensive coverage of the theoretical topics related to the jet descriptions (also thanks to the Run II jet physics), but I have several comments on how a user is suppose to use these jets:

Section: "Jets and ParticleJets" on Jet Analysis wiki.

Make links to Doxi or some other source of the information when "Jet" class is first mentioned (for the release 14) For the release 13, make also links to the "ParticleJet" class

Section: "Default jet collections" on Jet Analysis wiki.

The item: "Input type". If possible, make a link to the additional source of the information on "calorimeter towers at EM scale " and "topological clusters".

As a user, I would like to see recommendations about on what jet types should be used in certain situations ( towers vs topo, H1 calib vs LC). Which are better understood? What are possible drawbacks etc? Here I was left in complete darkness.

Finally, I would like to see examples on how a user can access a particular container with jet collections from an AOD file (truth, reconstructed), and what jet variables are available for the end user. This could be a link to some page or some other tutorial.

Section "Configuration of Jet algorithms" on Jet Analysis wiki

I'm not totally satisfied with this section: When I was reading this, I always had the question "how can I do all of this?". I want to see links to examples or descriptions of the following situations:

1) I'm building a jet filter, and I want to run a (KT, or Cone etc..) jet algorithm in my code using truth particle information. How can I do this? I want to see a generic line of the code which can be included to my analysis, like

Some_Jet_Algorithm::Some_Name algorithm( input collection )

Also, I would like to see an output from this algorithm, i.e. it would be good to illustrate how can I build a loop over all jet entries and print out some elementary output, like ET, Eta, Px, Py, Pz.

Then I want to see how can I customize the input parameters for a particular jet algorithm, how can I change the type of the algorithm, how can I change input collection.

A few specific examples are absolutely necessary.

2) The same for the reconstructed level (AOD or ESD) when I run over AOD/ESD files. I want to see a generic line of a code which shows how can I rerun my jet algorithm, how can I change the type of the algorithm. More importantly, what should I do to change the input . For example, for AOD, I would like to use "cluster" as input, or "MC truth list" or "tracks". For ESD, I also want to use "cells".

I found a bit disturbing the last page which says that it is difficult to reproduce AOD-build-in jets when I rerun the algorithm. This is difficult even for true-level particles? I do not see any technical reasons why I cannot reproduce true-level jets as long as the hadronic-final state at ATLAS is well defined in terms of the lifetime. Do we have such understanding?

Again, there should be a link to a few lines of the code which illustrate how can I access the output information from a jet algorithm and how to loop over jets and print several most important characteristics (PT, Eta, etc).

Obviously, I would like to see how can I customized a particular jet algorithm via the athena option.py file.

Also, I would like to find some other details, like which particles end up in a particular jet.

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Major updates:
-- SergeiChekanov - 16 Apr 2008

%RESPONSIBLE% SergeiChekanov
%REVIEW% Never reviewed