Jet	  azimuthal	  distribu0ons	  with	  high	  pT	  neutral	  pion	  triggers	  in	  pp	  collisions	  √s	  =	  	  7	  TeV	  from	  LHC-­‐ALICE	  	  	  	University	  of	  Tsukuba	  Daisuke	  Watanabe	  	2014/09/29	

1	

Outline	• Physics	  mo0va0on	  of	  π0-­‐jet	  correla0ons	  • A	  large	  Ion	  Collider	  Experiment	  (ALICE)	  • Analysis	  procedure	  • Results	  	  • Next	  step	  :	  Pb-­‐Pb	  analysis	  • Summary	  	2014/09/29	

2	

ICE DCal Addendum to the EMCal TDR

June 20100Physics	  mo0va0on	  of	  π -­‐jet	  correla0on	

(CERN-­‐LHCC-­‐2010-­‐011,	  ALICE-­‐TDR-­‐014-­‐ADD-­‐1)	

(Nucl.	  Phys.	  A839,	  255c)	

• Can	  II.2
control	  path	  length	  by	  tagging	  	  recoil	  jet	  centralwith	  triggered	  	  and	  changing	  Figure
Hadron+jet
correlations
ina200GeV
Au+Auπcollisions(M. pT	  for	  π 	  • High	  (STARpT	  of	  π0	  Collaboration)-­‐>	  longer	  path	  length	  Ploskon
2009).of	  recoiling	  jets	  00• Direct	  measurement	  of	  path	  length	  dependence	  of	  “jet”	  quenching,	  not	  by	  hadron	  • pp	  analysis	  is	  an	  important	  baseline	  for	  PbPb	  analysis	  2014/09/29	

II.3 DCal Physics

3	A	  Large	  Ion	  Collider	  Experiment	  (ALICE)	
Photon	  iden0ﬁca0on	  EMCal	  :	  Pb-­‐scin0llator	  calorimeter	  |η|	  <	  0.7,	  Δφ	  =	  110°	

Tracking	  ITS	  :	  Silicon	  tracker	  TPC	  :	  Time	  projec0on	  chamber	  |η|	  <	  0.9,	  Δφ	  =	  360°	
• Data	  set	  -­‐ pp	  collisions	  at	  √s	  =	  7	  TeV	  with	  EMCal	  triggered	  events	  	  -­‐ Number	  of	  events	  :	  10	  M	2014/09/29	

4	

Jet*Reconstruc2on*(FASTJET)

sequential clustering algorithms       jet	  reconstruc0on	  (FASTJET)	
$ p =Charged	  1 k algorithm
T&FastJet:
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2 p ΔRn(k ti ,k tj ) 2 % p = 0 Cambridge/Aachen algorithm
R &$ p = 1 k algorithm
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T' p = −1 2 panti-k
T &2 p ΔRdij = min(k ti ,k tj ) 2 % p = 0 Cambridge/Aachen algorithm
R &f Jet Findinganti-kT algorithm' p = −1
arXiv:0802.1189v2
2icle distance : dij
m distanceProcedure: d =k 2p
of Jet Finding
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ij or diB) particle distance : dij
1. Calculate	  par0cle	  distance	  :	  dij	  st combine
particles
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If	  dibthe	  andis	  scluster
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[hep-pn] (2008)

KT jet Cone jet

arXiv:0802.1189v2[hep-pn] (2008)

KT

largerthan	  thantthreshold	  	  	  	  	  	  	  	  	  	  	  	  momentum	  larger	  hreshold	  	  callthe	  theccluster
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2014/09/29	

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5	

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455
456

NLM = 1 (2 cases), NLM= 2 and12,
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12	

Back	  up	

2014/09/29	

13	

Charged	  par0cle	  jets	  spectra	  and	  full	  jet	  RAA	Systematic uncertainty added quadraticallyCorrected spectrum
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2014/09/29	

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