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2015:groups:sm:qg [2015/06/04 17:06]
jesse.thaler [Basic Plan]
2015:groups:sm:qg [2015/06/06 17:33]
philippe.gras
Line 6: Line 6:
   * Jon Butterworth   * Jon Butterworth
   * Mario Campanelli   * Mario Campanelli
-  * Marat Freytsis+  * Marat Freytsis ​<​freytsis@physics.harvard.edu>​
   * Peter Loch <​loch@physics.arizona.edu>​   * Peter Loch <​loch@physics.arizona.edu>​
-  * Deepak Kar +  * Deepak Kar <​deepak.kar@cern.ch>​ 
-  * Andrzej Siodmok+  * Simon Plätzer 
 +  * Andrzej Siodmok ​<​andrzej@cern.ch>​
   * Peter Skands <​peter.skands@monash.edu>​   * Peter Skands <​peter.skands@monash.edu>​
   * Dave Soper   * Dave Soper
Line 15: Line 16:
   * Frank Tackmann   * Frank Tackmann
   * Jesse Thaler <​jthaler@mit.edu>​   * Jesse Thaler <​jthaler@mit.edu>​
 +  * Philippe Gras <​philippe.gras@cern.ch>​
   * ...   * ...
  
Line 141: Line 143:
   * Question: ​ Sum over particles (angularity-style) vs. sum over pairs (ECF-style)   * Question: ​ Sum over particles (angularity-style) vs. sum over pairs (ECF-style)
     * Answer: ​ Sum over particles (angularity-style)     * Answer: ​ Sum over particles (angularity-style)
 +  * Question: ​ Plot linear or log scale?
 +    * Answer: ​ Do both if it makes sense, better for angularities to have log scale.
  
 ==== Supplemental Jet Shapes ==== ==== Supplemental Jet Shapes ====
Line 160: Line 164:
  
   * Rivet analysis in place which computes from a HepMC event sample the various generalised angularity distributions.   * Rivet analysis in place which computes from a HepMC event sample the various generalised angularity distributions.
 +  * Processes to consider:
 +    * mu+mu- -> spin1 -> q qbar  take photons
 +    * mu+mu- -> spin0 -> g g  take Higgs
 +    * for tests of universality: ​ mu+mu- -> spin0 -> q qbar
 +  * Energies
 +    * Q=sqrt{s} = 50, 200, 800 GeV
 +    * Optionally: ​ Q = 100, 400 GeV
 +  * Jet definition:
 +    * ee-antikt [genkt, p=-1], WTA_modp recomb scheme
 +    * R = 0.3, 0.6, 0.9
 +  * Add thrust from thrust hemispheres for anticipated analytic comparisons
 +  * Add multiplicity (event-wide) in bins of thrust:
 +     * T < 5 GeV/sqrt(S)
 +     * 5 GeV/sqrt(S) < T < 0.1
 +     * 0.1 < T < 0.2
 +     * 0.2 < T
 +
 +==== Preliminary plots for meeting on Thursday ====
 +
 +{{:​2015:​groups:​sm:​ga_10_20.pdf|}}
 +{{:​2015:​groups:​sm:​ga_10_10.pdf|}}
 +{{:​2015:​groups:​sm:​ga_10_05.pdf|}}
 +{{:​2015:​groups:​sm:​ga_00_00.pdf|}}
 +{{:​2015:​groups:​sm:​ga_20_00.pdf|}}
  
 ==== Questions ==== ==== Questions ====
  
   * Is discrimination power (e.g. for width) coming from the hadronization regime?   * Is discrimination power (e.g. for width) coming from the hadronization regime?
-  ​+    ​Possibility: ​ Isolate hadronization regime (thrust ~ LambdaQCD/​Q) and shower regime (thrust ~ 0.1-0.2) and optionally hard jet regime (thrust >~ 0.25). ​ Study scaling of, e.g., multiplicity as a function of Q in each of these regimes. 
 +  * By testing pythia vs. herwig, can we test string vs. cluster hadronization?​ 
 +  * Is there jet radius dependence?​ 
 +  * Does matching help in controlling quark/gluon uncertainties?​ 
 +  * Universality/​process dependence of conclusions?​ 
 +    * Related to whether the discrimination power comes from the core or the periphery of jet. 
 ===== Next Les Houches Study (for after LH) ===== ===== Next Les Houches Study (for after LH) =====
  
   * Above study at hadron colliders, using dijets, W/Z/gamma + j, and maybe t tbar samples   * Above study at hadron colliders, using dijets, W/Z/gamma + j, and maybe t tbar samples
  
-===== Preliminary plots for meeting on Thursday ​=====+===== Analytic Les Houches Study? ​=====
  
-{{:2015:​groups:​sm:​ga_10_20.pdf|}} +  * Analytic predictions known/​available/​straightforward for
-{{:2015:​groups:​sm:​ga_10_10.pdf|}} +    * Quark thrustN^3LL' + N^3L0 
-{{:2015:​groups:​sm:​ga_10_05.pdf|}} +    * Gluon thrustN^2LL' + N^2L0 
-{{:2015:​groups:​sm:​ga_00_00.pdf|}} +    * ang (kappa =1) ​NLL'​ 
-{{:​2015:​groups:​sm:​ga_20_00.pdf|}}+  * Can we do useful quark/gluon study from analytic results?
  
 ===== Notes from Tuesday Meeting ===== ===== Notes from Tuesday Meeting =====
Line 377: Line 411:
  
 </​code>​ </​code>​
 +
 +===== Notes for Jesse for Preparing Summary Talk =====
 +
 +  * Quark is more of an adjective than a noun.
 +  * Pseudo-quark? ​ (That language doesn'​t go over very well.)
 +
 +==== What is a Quark Jet? ====
 +
 +(From ill-defined to well-defined)
 +
 +  * A quark parton
 +  * A Born-level quark parton
 +  * The initiating quark parton in a final state shower
 +  * An eikonal line with baryon number 1/3 and carrying triplet color charge
 +  * A quark operator that appears in a hard matrix element in the context of a factorization theorem.
 +  * A parton-level jet object that has been tagged as a quark using a soft-safe flavored jet algorithm (automatically collinear safe if you sum constituent flavors).
 +  * A phase space region (as defined by an unambiguous hadronic fiducial cross section measurement) that yields an enriched sample of quarks (as interpreted by some suitable, though fundamentally ambiguous, criterion).  ​
 +  ​
 +(Sometimes people think we care about the top of the list while we are really focused entirely on the bottom.)
2015/groups/sm/qg.txt · Last modified: 2015/07/14 08:27 by philippe.gras