The	  Study	  Of	  Direct	  Photon	  Azimuthal	  Anisotropy	  At	  RHIC-­‐PHENIX	  Experiment	Sanshiro	  Mizuno	  for	  PHENIX	  collabora7on	  University	  of	  Tsukuba,	  RIKEN	  30pTR-­‐10	  What	  is	  Azimuthal	  Anisotropy?	
1X
d3 N
E 3 / [1 + 2⌫n cos{n(dpn=1⌫n =< cos{n(n )}]n )} >

Event	  Plane(Φn)	  :	  	  The	  base	  direc7on	  for	  expansion	  vn	  :	  strength	  of	  anisotropy	  Azimuthal	  anisotropy	  is	  rela7ve	  devia7on	  of	  the	  number	  of	  emiJed	  	  par7cle	  between	  in	  and	  out	  of	  plane.	  	  It	  is	  strongly	  related	  to	  iniPal	  geometry	  and	  η/s	  of	  QGP.	  
Expansion	  makes	  anisotropy	  in	  momentum	  space.	  
2014/03/30	

JPS	  @	  University	  of	  Tokai	

2	Higher	  Order	  Anisotropy	
Φ3	1X
d3 N
E 3 / [1 + 2⌫n cos{n(dpn=1⌫n =< cos{n(n )}]n )} >

Φ2	 Event	  Plane(Φn)	  :	  	  The	  base	  direc7on	  for	  expansion	  vn	  :	  strength	  of	  anisotropy	  Ini7al	  geometry	  is	  deformed	  because	  of	  sta7s7cs	  ﬂuctua7on.	  
It	  makes	  higher	  order	  azimuthal	  anisotropy.	  	  It	  is	  important	  to	  constrain	  ini7al	  geometry	  calcula7ng	  model	  and	  	  η/s	  of	  QGP.	  
2014/03/30	

JPS	  @	  University	  of	  Tokai	

3	What	  is	  Direct	  Photon?	
Direct	  photon	  is	  all	  photons	  except	  ones	  from	  hadron	  decay.	  
l PenetraPng	  QGP	  without	  scaXering	  l Created	  from	  various	  sources	  Direct	  photon	
prompt	  	  photon	

thermal	  	  photon	parton	  	  Jet	  fragmentaPon	
energy	  loss	

photon	  from	  hadron	  decay	2014/03/30	

Inclusive	  photon	
JPS	  @	  University	  of	  Tokai	

4	Direct	  Photon	  Azimuthal	  Anisotropy	
It	  is	  expected	  that	  the	  photon	  sources	  are	  iden7ﬁed	  by	  azimuthal	  	  anisotropy	  measurement	  (ini7al	  geometry	  dependence).	  	  Jet	  • prompt	  :	  v2~0	  • Jet	  fragmentaPon	  :	  v2>0	  • parton	  energy	  loss	  :	  v2<0	  • thermal	  QGP	  :	  v2≥0	  • thermal	  HG	  :	  v2>0	  fragmentaPon	

Energy	  loss	

Superposi7on	  is	  measured.	  	  	  γdir.	  v2	  has	  been	  measured	  at	  PHENIX	  and	  ALICE.	  
2014/03/30	

JPS	  @	  University	  of	  Tokai	

5	Direct	  Photon	  v2	  P.R.L.	  109,	  122302(2012)	

pT[GeV/c]	

γdir.	  v2	  is	  close	  to	  0	  in	  high	  pT,	  which	  is	  consistent	  with	  expecta7on.	  
It	  has	  strong	  v2	  as	  one	  of	  hadron	  in	  low	  pT.	  	  ALICE	  also	  measure	  γdir.	  v2	  and	  it	  is	  found	  that	  it	  has	  similar	  trend.	  
2014/03/30	

JPS	  @	  University	  of	  Tokai	

6	DeviaPon	  of	  Temperature	  Tγ	  =	  233±14±19	  MeV	  is	  observed	  by	  direct	  	  photon	  spectrum.	  
It	  is	  much	  higher	  than	  Thad	  =	  100-­‐120	  MeV	  	  which	  is	  freeze-­‐out	  temperature.	  

Tγ	  >>	  Thad	  	  	  
Azimuthal	  anisotropy	  is	  created	  from	  	  ini7al	  geometry	  deforma7on.	  
It	  is	  needed	  the	  enough	  expansion	  7me	  	  to	  have	  large	  v2.	  
Tγ	  ~	  Thad	  2014/03/30	

JPS	  @	  University	  of	  Tokai	

γdir.	  v2	pT(GeV/c)	

7	

UnderesPmaPon	  for	  γdir.	  v2	  γdir.	  v2	P.R.C	  77,024909(2008)	

Model	  calcula7on	  is	  	  underes7mated	  for	  v2	  	  while	  spectra	  is	  well	  	  PHENIX	  Jet-­‐QGP	  described.	  
prompt-­‐frag.	  	  Thermal	  QGP	  Addi7onal	  component	  	  QGP+prompt+HG	   is	  needed	  to	  describe	  	  experiment	  results.	  	  • Strong	  magnePc	  ﬁeld	  • Blue	  shic	  pT(GeV/c)	

2014/03/30	

JPS	  @	  University	  of	  Tokai	

8	What	  makes	  large	  v2?	  

B	

MagnePc	  Field	  eﬀect	  2nd	  of	  Event	  Plane	  is	  strongly	  correlated	  	  with	  Reac7on	  Plane	  while	  3rd	  is	  not.	  
v2	  is	  strong	  :	  v3	  is	  weak	  	  ~B?R.P.

Blue	  shic	  eﬀect	  Observed	  temperature	  is	  aﬀected	  by	  	  sﬂow	  and	  it	  is	  overes7mated.	  
1+ < >
v2	  and	  v3	  are	  strong	  Tobs ⇠ Treal
1 < >	  	  <β>	  :	  average	  expansion	  	  v3	  measurement	  helps	  to	  understand.	 velocity	
2014/03/30	

JPS	  @	  University	  of	  Tokai	

9	Analysis	  ﬂow	ü π0	  and	  γinc.	  vn	  measurement	  	  ü γdec.	  vn	  simula7on	  It	  is	  simulated	  from	  π0	  vn.	  	  ü γdir.	  vn	  calcula7on	

Rdir.
⌫n =⌫ninc.
R⌫ndec.

413

R = N inc. /N dec.

Rγ	2

10

5

10

15pT(GeV/c)

2014/03/30	

JPS	  @	  University	  of	  Tokai	

10	Summary	
Direct	  photon	  is	  powerful	  tools	  to	  study	  QGP.	  
Azimuthal	  anisotropy	  is	  related	  with	  ini7al	  geometry.	  
Higher	  order	  is	  thought	  to	  be	  more	  important.	  	  Direct	  photon	  v2	  has	  been	  measured	  at	  PHENIX	  and	  ALICE.	  
It	  is	  found	  that	  it	  has	  as	  strong	  v2	  as	  hadron,	  but	  it	  is	  not	  yet	  	  understood.	  
Model	  calcula7on	  is	  underes7mated.	  	  	  Direct	  photon	  v3	  is	  expected	  to	  help	  understanding.	  
Measurement	  is	  ongoing.	  
2014/03/30	

JPS	  @	  University	  of	  Tokai	

11	

2014/03/30	

JPS	  @	  University	  of	  Tokai	

12	

BACK	  UP	2014/03/30	

JPS	  @	  University	  of	  Tokai	

13	2nd	  and	  3rd	  of	  Event	  Plane	  correlaPon	  < cos {6(A3B2 )} >It	  is	  known	  that	  they	  have	  	  weak	  correla7on.	  	  It	  is	  considered	  that	  3rd	  	  order	  of	  Event	  Plane	  is	  	  deﬁned	  as	  a	  deforma7on	  	  of	  ini7al	  geometry.	

Centrality	  (%)	2014/03/30	

JPS	  @	  University	  of	  Tokai	

14	Event	  Plane	⌫n =< cos{n(n )} >The	  angles	  of	  par7cle	  emission	  and	  Event	  Plane	  are	  measured	  by	  	  diﬀerent	  detectors	  in	  order	  to	  auto-­‐correla7on	  (e.g.	  Jet).	  
Event	  Plane	  is	  determined	  as	  a	  strong	  direc7on	  of	  ﬂow.	

Qx =< wi cos(n i ) >Qy =< wi sin(n i ) >n = atan2(Qy , Qx )/n2014/03/30	

i	  :	  direc7on	  of	  detector	  wi	  :	  weight	

JPS	  @	  University	  of	  Tokai	

15	

QGP	  temperature	  measurement	
Direct	  photon	  at	  low	  pT	  provides	  	  temperature	  of	  QGP.	  	  Teﬀ	  =	  233	  ±	  14	  ±	  19	  MeV	  (Min.	  Bias.)	  Tini	  =	  300~600	  MeV	  	  Teﬀ(LHC)	  =	  304±51	  MeV	  (2.76TeV,0-­‐40%)	  	  	  T	  =	  170MeV	  (Lalce	  QCD)	  T	  =	  100-­‐120MeV	  (hadron	  freeze-­‐out)	  	  The	  photon	  from	  hot	  maJer	  is	  observed.	  

2014/03/30	

JPS	  @	  University	  of	  Tokai	

16	γdir.	  is	  not	  suppressed	  	RAA =evt 2(1/NAA)d NAA /dpT dyinel ⇥ d2
< Ncoll > / pp
pp /dpT dy

Hadron	  is	  	  suppressed.	

RAA	  of	  direct	  photon	  is	  consistent	  with	  unity	  in	  high	  pT.	  
This	  is	  consistent	  with	  the	  expecta7on	  that	  γdir.	  coming	  from	  ini7al	  	  scaJering	  is	  dominant.	  
JPS	  @	  University	  of	  Tokai	
2014/03/30	
17	

Measurement	  of	  higher	  order	  vn	

P.R.L.	  107,	  252301(2011)	

v2	  	  v3	  	  v4	v3	  and	  v4	  have	  weak	  centrality	  dependence	  while	  v2	  has	  strong.	  
It	  indicates	  v3	  and	  v4	  are	  created	  by	  the	  ini7al	  geometry	  deforma7on.	  
2014/03/30	

JPS	  @	  University	  of	  Tokai	

18	PID	  vn	  measurement	
200 GeV Au+Au 0-50%v2{Φ2}

0.2

π+πK+K
pp

0.15

Vn

0.2

PHENIX Preliminaryv3{Φ3}x1.5

0.2

v4{Φ4}x1.50.2

 -

0.15

0.15

0.15

0.1

0.1

0.1

0.1

0.05

0.05

0.05

0.05

0000:pT0v4{Φ2}x5.0

correlated sys. of π±123401234012340

1234

pT [GeV/c]vn	  has	  mass	  and	  meson/baryon	  dependence.	  
Higher	  harmonics	  are	  created	  from	  ini7al	  geometry	  deforma7on,	  	  they	  are	  aﬀected	  by	  the	  eﬀect	  of	  QGP	  expansion.	  
2014/03/30	

JPS	  @	  University	  of	  Tokai	

19	KET	  scaling	  for	  PID	  vn	200 GeV Au+Au 0-50%

0.1 v {Φ }/n22q0.1 v {Φ }/n x1.5
44q0.1 v {Φ }/n x5.0
42q0.08  

0.08

0.08

0.06

0.06

0.06

0.040.04

0.04

0.04

0.02

0.02

0.02

0.02

0000π+π-0.08

V n/nqPHENIX Preliminary

0.1 v {Φ }/n x1.5
33qK+Kpp0.06-

:KET correlated sys. of π±-0.02

00.5

1

1.5-0.02
2 00.5

11.5-0.02
2 00.5

11.5-0.02
2 00.5

11.5

2KET/nq [GeV]

Meson	  is	  scaled	  well,	  while	  proton	  isn’t	  scaled.	
2014/03/30	

JPS	  @	  University	  of	  Tokai	

20	γdir.	  measurement	  by	  ALICE	 arXiv:1212.3995v2	v2	

Similar	  trend	  with	  RHIC-­‐PHENIX	  is	  observed	  by	  LHC-­‐ALICE.	

2014/03/30	

JPS	  @	  University	  of	  Tokai	

21	Strong	  magnePc	  ﬁeld	  eﬀect	arXiv:1206.1334v2	

B	

Strong	  magne7c	  ﬁeld	  is	  thought	  to	  aﬀect	  photon	  emit	  angle.	  
It	  is	  created	  in	  perpendicular	  direc7on	  to	  Reac7on	  Plane.	
2014/03/30	

JPS	  @	  University	  of	  Tokai	

22	Quark	  annihilaPon	  eﬀect	

Late	  state	  photon	  produc7on	  with	  q-­‐q	  annihila7on	  eﬀect	  seems	  	  to	  work	  well.	
JPS	  @	  University	  of	  Tokai	
2014/03/30	
23	arXiv:1308.2440v2	

Measured	  temperature	  is	  shioed	  from	  real	  temperature	  due	  to	  ﬂow	  eﬀect.	  

2014/03/30	

JPS	  @	  University	  of	  Tokai	

24	Thermal	  photon	  v2	

P.R.L.	  96,202302(2006)	

Much	  smaller	  than	  PHENIX	  direct	  photon	  v2.	

2014/03/30	

JPS	  @	  University	  of	  Tokai	

25	PHENIX	  detector	
CNT	  coverage	  |η|<0.35	  φ	  :	  180	  	  • Tracking	  detector	  DC,	  PC1,	  PC2,	  PC3	  • par7cle	  iden7ﬁca7on	  RICH,	  TOF,	  AGEL,	  EMCal	  EMCal	  is	  used	  to	  detect	  photon.	  
PC3	  is	  used	  to	  remove	  charged	  par7cle.	  	  Event	  Plane	  is	  measured	  by	  RxN	  detector.	  
2014/03/30	

JPS	  @	  University	  of	  Tokai	

26	Check	  to	  be	  consistent	  with	  π±	  v3	  	0-10 %

0.1

0.1

10-20 %

0.1

20-30 %

0.1

30-50 %

π0 ν3
π± ν3
0.05

0.05

0.05

E.P.RxN

Au+Au(|η|=1.0-2.8)

sNN=200GeV

0002

40pT (GeV/c)

0.05

 
02

40pT (GeV/c)

0240pT (GeV/c)

24pT (GeV/c)π0	  v3	  is	  measured	  up	  to	  4.0	  GeV/c	  with	  several	  centrali7es.	  
It	  is	  conﬁrmed	  to	  be	  consistent	  with	  π±	  v3.	  	  Decay	  photon	  vn	  is	  simulated	  from	  π0	  and	  the	  other	  meson	  v3.	
2014/03/30	

JPS	  @	  University	  of	  Tokai	

27	PHENIX	  CNT	  DETECTORS	  IN	  SIDE	  VIEW	• BBC(3.1<|η|<3.8)	  • MPC(3.1<|η|<3.8)	  • RxN(1.0<|η|<2.8)	  Event	  are	  classiﬁed	  by	  these	  detectors.	  
Event	  Plane	  are	  measured	  by	  these	  detectors.	

2014/03/30	

JPS	  @	  University	  of	  Tokai	

28	Event	  Plane	  calculaPon	

2nd	  Event	  Plane	  correlaPon	
RxN(In)S&N	  RxN(Out)S&N	  RxN(In+Out)S&N	

Centrality[%]	
2014/03/30	

ReacPon	  Plane	  detector(RxN)	  Inner	  	  :	  1.5	  <	  |η|	  <	  2.8	  Outer	  :	  1.0	  <	  |η|	  <	  1.5	  2nd	  Event	  Plane	  resoluPon	

Res{Ψn}	

<cos{n(Ψn,A-­‐Ψn,B)}>	

Event	  Plane	  is	  calculated	  by	  three	  steps.	  
1.	  gain	  correcPon	  2.	  re-­‐centering	  3.	  ﬂaXening	  JPS	  @	  University	  of	  Tokai	

RxN(In)S+N	  RxN(Out)S+N	  RxN(In+Out)S+N	
Centrality[%]	

29	120
1001000.8800(c)2040

spectra+v4	  0.88060 0(d)0.1 0.1

2040600.1	  0.05

0.05 0.05

00.05

0 00204060002040

sn

spectra+v4(Ψ2)	

sn	  geometrical	  anisotropy	ρn	  velocity	  ρnanisotropy	

0.1

ρ0140

1.2
1.2(b)
v2spectra+v+spectra
v3+spectra 2	  140 PHENIX	  Preliminary	v4	  +spectra
v4spectra+v{Φ 2}+spectra3	1 1201<ρ0>	  average	  velocity	

Tf	  Tf [MeV]temperature	

(a)

60

Centrality %ρn	  behavior	  is	  similar	  to	  centrality	  dependence	  of	  charged	  par7cle	  vn.	  
s3	  and	  s4	  are	  smaller	  than	  s2	  but	  not	  zero	  in	  non-­‐central.	

2014/03/30	

JPS	  @	  University	  of	  Tokai	

30	

B	

It	  is	  es7mated	  about	  1017[Gauss].	  	  It	  related	  to	  photon	  produc7on	  angle??	

2014/03/30	

JPS	  @	  University	  of	  Tokai	31