Level 3 Jet Tool

Camille Champagne-Belanger, Chris Potter and Brigitte Vachon
McGill University

The Level 3 jet code is located primarily in the packages l3tCalUnpTool, l3tcalcluster and l3fjettools. The calorimeter unpacker package effects the calorimeter cell unpacking and hot cell killing. The clusterer does preliminary clustering of the calorimeter cells. The jet package uses calorimeter clusters to make jets by further clustering the calorimeter cells and applying quality cuts. For documentation of the latter two packages, see the l3fjettools documentation and the l3tcalcluster documentation, both written by Volker Buescher.

There are currently two tools in use for Level 3 jets, SCJET_8 and SC5JET_9_PV3. Both use the simple cone algorithm for clustering, the former with cone size 0.7 and the latter with cone size 0.5. The former has a minimum Et cut of 8 GeV while the latter has a minimum Et cut of 9 GeV. The latter also uses a primary vertex (from tracks with a minimum pt of 3 GeV), if one is found, to calculate eta and phi of the jet. For complete descriptions see

SCJET_8 (discontinued since trigger list global_CMT-15.20)
SC5JET_9_PV3

for the tool term reports. The calorimeter clusterer and unpacker tool term reports are also linked from these pages.

Completed code developments for RunIIb now in p19 and p20 include:

Implementation of Level 1 jet confirmation at Level 3. See Camille's most recent talks (here and here) and Section 2 of D0Note 5130 .
Removal of spurious jets seen in Run IIa. See D0Note 5092.

Certification studies for RunIIb Level 3 Jets:

Preliminary study in p19.L3.01. See D0Note 5130 v1.
Final study for RunIIb. See D0Note 5130 v2.

Other studies include:

Jet Energy Scale Correction at Level 3. See Section 6 of D0Note 5130 .
Electron Removal Filter. See Section 5 of D0Note 5130 .

Useful links:

Links to Camille's L3 talks and Chris' L3 talks.
The previous Level 3 Jets page, which includes p16 Level 3 jets certification and some useful (if slightly outdated) instructions on using TrigSim.
Current instructions for using TrigSim.
Helpful recipes from Kevin Chan on using offline reconstruction, TrigSim and TMBAnalyze. See the latter for getting the L3 offline chunk made with TrigSim into the CAF trees.
A description of the level3.sim file by Gustaaf Brooijmans.
Some instructions for using CVS from Daniela Bauer.
The offline Jet ID page and the offline Jet ID documentation.

Relevant D0 Notes:

D0Note 5130: Certification of Level 3 Jets for RunIIb.
D0Note 5092: The Rejection of Spurious Low ET Level 3 Jets Found in RunIIa [newly implemented in L3]
D0Note 4932: Improved L1 Confirmation [offline, newly implemented in L3]
D0Note 4919: Jet ID Optimization [offline reconstruction]
D0Note 4457: Jet Algorithms in the D0 Run II Software: Description and User's Guide [offline reconstruction]
D0Note 4146: Technical Description of the T42 Algorithm for the calorimeter noise suppression [offline, not implemented in L3]
D0Note 3687: NADA, A New Event by Event Hot Cell Killer [offline reconstruction, implemented in L3]

This page is maintained by Chris Potter (cpotter@physics.mcgill.ca). Last modified 6 April 2007.