1 | Note on the implementation of the CMS Iterative Plugin |
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2 | |
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3 | The code is initially the CMSSW implementation in |
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4 | CMSIterativeConeAlgorithm.cc in /CMSSW/RecoJets/JetAlgorithms |
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5 | (more precisely, Revision 14 of the cc file) |
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6 | |
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7 | To avoid importing too many files from CMSSW, we did a couple of |
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8 | modifications starting from the CMSIterativeConeAlgorithm file: |
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9 | |
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10 | - directly used the FastJet PseudoJet instead of the InputItem |
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11 | present initially. Note that access to the info then has to be done |
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12 | using . instead of -> which implies a few small modifications here |
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13 | and there. |
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14 | |
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15 | - added a small piece of code to compute Et. That peice of code is |
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16 | the same as tracked down in the CMS code. It comes from the Root |
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17 | Lorentzvector, more precisely, the PxPyPzE4D implementation. |
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18 | |
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19 | - The ordering in Et, NumericSafeGreaterByEt, is imported from |
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20 | EtComparator.h in PhysicsTools/Utilities/ |
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21 | |
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22 | - The DeltaR2 computation is imported from DeltaR.cc and DeltaPhi.cc |
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23 | in CMSSW/DataFormats/Math |
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24 | |
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25 | - finally, instead of the ProtoJet construction, we use the |
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26 | ClusterSequence-compatible clustering. That one follows the line of |
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27 | what is done in the SISCone plugin. Note that ve've checked in the |
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28 | CMSSZ code that the protojet is indeed reconstructed using E-scheme |
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29 | recombination (while the stability test is done using Et-scheme) |
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30 | |
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31 | Finally, we want to thank Andreas Oehler for pointing us to the CMS |
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32 | code. |
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