Jet Substructure

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* Colour singlet heavy objects, two body decay (W,Z,H...) ===
* Colour singlet heavy objects, two body decay (W,Z,H...) ===
** [http://www.slac.stanford.edu/spires/find/hep/www?irn=7662955 Butterworth+] W/Z+higgs (Cambridge/Aachen)
** [http://www.slac.stanford.edu/spires/find/hep/www?irn=7662955 Butterworth+] W/Z+higgs (Cambridge/Aachen)
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** ttbar higgs [http://cms.cern.ch/iCMS/jsp/openfile.jsp?type=TS&year=2007&files=TS2007_001.pdf CMS study] No substructure used yet...
+
** [http://www.slac.stanford.edu/spires/find/hep/www?irn=4825381 Butterworth+] WW (kT y scales)
 +
** The above analysis was carried out with a full detector simulation in the WW scattering chapter (p1769) of [http://www.slac.stanford.edu/spires/find/hep/www?irn=8103593 this big ATLAS paper].
 +
** ttH [http://cms.cern.ch/iCMS/jsp/openfile.jsp?type=TS&year=2007&files=TS2007_001.pdf CMS study] No substructure used yet...
 +
** ttH Atlas (Reference, Simon?)
* Colour singlet heavy objects, three body decay (Neutralino,...) ===
* Colour singlet heavy objects, three body decay (Neutralino,...) ===
 +
** [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0906.0728 Butterworth+] neutralinos (kT yscales and Cambridge/Aachen)
 +
** ATLAS public note (SUSY09) on [http://cdsweb.cern.ch/record/1177832 neutralinos from subjet structure]
 +
** [http://www.slac.stanford.edu/spires/find/hep/www?eprint=hep-ph/0702150 Butterworth+] W,Z,H in SUSY cascades (kT y scale again)
* Coloured heavy objects (top,...) ===
* Coloured heavy objects (top,...) ===
** [http://www.slac.stanford.edu/spires/find/hep/www?key=7777973 Kaplan+] top tagging
** [http://www.slac.stanford.edu/spires/find/hep/www?key=7777973 Kaplan+] top tagging
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** [http://indico.cern.ch/materialDisplay.py?contribId=23&materialId=slides&confId=46139 Schwartz talk] (May 18, 2009)
+
** [http://indico.cern.ch/materialDisplay.py?contribId=23&materialId=slides&confId=46139 Schwartz talk] on top-tagging(May 18, 2009)
 +
** [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0810.0934 Almeida+] and [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0807.0234 Almeida+] top event shapes
== MC issues ==
== MC issues ==
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POWHEG in Higgs decays. Dead cones etc. ''Keith Hamilton, Giacinto Piacquadio, Matt Schwartz, Leif? to produce a short summary of the effects implemented in different MCs.''
POWHEG in Higgs decays. Dead cones etc. ''Keith Hamilton, Giacinto Piacquadio, Matt Schwartz, Leif? to produce a short summary of the effects implemented in different MCs.''
-
Keith's slides on Dead Zones to link here.
+
* Keith's slides on Dead Zones to link here.
 +
* [http://www.slac.stanford.edu/spires/find/hep/www?eprint=hep-ph/0612236 Hamilton+] Showers for top decay
'''How sensitive are the various subjet methods to the above differences?'''
'''How sensitive are the various subjet methods to the above differences?'''
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Constituents = final state particles, or pre-clustered final state particles, or towers, or topoclusters...
Constituents = final state particles, or pre-clustered final state particles, or towers, or topoclusters...
-
== Incomplete set of jet substructure references ==
+
== Miscellaneous References ==
  * [http://www.slac.stanford.edu/spires/find/hep/www?irn=2836785 Seymour+] clustering (kT algorithm)
  * [http://www.slac.stanford.edu/spires/find/hep/www?irn=2836785 Seymour+] clustering (kT algorithm)
-
* [http://www.slac.stanford.edu/spires/find/hep/www?irn=4825381 Butterworth+] WW (kT y scales)
 
-
* The above analysis was carried out with a full detector simulation in the WW scattering chapter (p1769) of [http://www.slac.stanford.edu/spires/find/hep/www?irn=8103593 this big ATLAS paper].
 
-
* [http://www.slac.stanford.edu/spires/find/hep/www?eprint=hep-ph/0702150 Butterworth+] W,Z,H in SUSY cascades (kT y scale again)
 
  * [http://www.slac.stanford.edu/spires/find/hep/www?irn=3590534 Dokshitzer+] clustering
  * [http://www.slac.stanford.edu/spires/find/hep/www?irn=3590534 Dokshitzer+] clustering
-
* [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0810.0934 Almeida+] and [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0807.0234 Almeida+] top event shapes
 
-
* [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0906.0728 Butterworth+] neutralinos (kT yscales and Cambridge/Aachen)
 
-
* ATLAS public note (SUSY09) on [http://cdsweb.cern.ch/record/1177832 neutralinos from subjet structure]
 
  * [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0903.5081 S. Ellis+] jet pruning, using top as an example
  * [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0903.5081 S. Ellis+] jet pruning, using top as an example
  * [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0903.0392 Krohn+] variable R
  * [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0903.0392 Krohn+] variable R
  * Top ID using kT y scales [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0802.3715 this Les Houches report] (p106)
  * Top ID using kT y scales [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0802.3715 this Les Houches report] (p106)
  * [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0803.0883 Bahr+] Herwig++ manual (includes heavy particle decays)
  * [http://www.slac.stanford.edu/spires/find/hep/www?eprint=arXiv:0803.0883 Bahr+] Herwig++ manual (includes heavy particle decays)
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* [http://www.slac.stanford.edu/spires/find/hep/www?eprint=hep-ph/0612236 Hamilton+] Showers for top decay
 

Revision as of 12:02, 12 June 2009

Back to Tools_and_Monte_Carlo_Session_1_(SM)#Jet_Physics.

Boosted hadronic decays of massive particles (W,Z,Top,H,BSM..., with session 2) and jet mass/shape studies with QCD jets in early data.

Interested parties (Session 1)

Matt Schwartz, Giacinto Piacquadio, Mario Campanelli, Paulo Francvilla, Jon Butterworth, Peter Loch, Ezio Maina, Leif Lonnblad, Keith Hamilton, Simon Dean, Rohini Godbole, ...

Examine/discuss the different regions of validity for calculations of variables like jet mass, jet width, subjet multiplicity, using e.g. (N)LO ME, PS, matched and resummed calculations etc... (see also A Collection of Matching Benchmarks). Review, compare, critique literature, think about future ideas.

Recent preprint on Zbb and Wbb at NLO.

Contents

Types of object one might use substructure on

QCD jets (quark gluon separation)

  • Wjj provides a sample of quark jets at LHC?
  • SUSY cascades are rich in quark jets. Could use quark ID to simplify decay chains.

Heavy objects

  • Substructure tagging minireview. (Schwartz...)
  • Colour singlet heavy objects, two body decay (W,Z,H...) ===
    • Butterworth+ W/Z+higgs (Cambridge/Aachen)
    • Butterworth+ WW (kT y scales)
    • The above analysis was carried out with a full detector simulation in the WW scattering chapter (p1769) of this big ATLAS paper.
    • ttH CMS study No substructure used yet...
    • ttH Atlas (Reference, Simon?)

MC issues

Differences in heavy object decays; different parton showers, matrix element corrections in some MC, not in others; in Herwig, Herwig++, pythia, sherpa. POWHEG improvement soon. See talk from Carlo Oleari Friday afternoon for some discussion of MC@NLO and POWHEG in Higgs decays. Dead cones etc. Keith Hamilton, Giacinto Piacquadio, Matt Schwartz, Leif? to produce a short summary of the effects implemented in different MCs.

  • Keith's slides on Dead Zones to link here.
* Hamilton+ Showers for top decay

How sensitive are the various subjet methods to the above differences?

Would be nice to have some truth level comparisons, of simple variables (jet mass etc) and also of some of the various boosted decay methods (esp top?) if possible.

Detector issues

Pile-up, calorimeter noise, granularity.

Slides from Peter Loch to be linked here.

Studies from GP.

Proposed cuts for studying this (highest priority ones in bold):

  • pT cut on constituents (MeV) 0,100,500,1000,2000.
  • QCD jets in pT bins between 17,35,70,140,280,560,1120 GeV. Look at the leading jet. Radipity +/- 5.
  • Pile-up. 0,4,8,16-20 interactions per signal event (Poisson). (Think about doing this as a function of number vertices in full sim).
  • Jet algorithms. Use Anti-kT R=0.4, R=0.6. And also C/A, kT etc where appropriate, and also studies of using e.g. C/A to recluster anti-kT jets




Find the jet first, then cut on constituents, or cut on constituents first then find the jet?

Constituents = final state particles, or pre-clustered final state particles, or towers, or topoclusters...

Miscellaneous References

* Seymour+ clustering (kT algorithm)
* Dokshitzer+ clustering
* S. Ellis+ jet pruning, using top as an example
* Krohn+ variable R
* Top ID using kT y scales this Les Houches report (p106)
* Bahr+ Herwig++ manual (includes heavy particle decays)
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