Heavy Flavor and Charged Hadron Flow measurement using

Silicon Vertex Detector at PHENIX

Hiroshi Nakagomi for the SVX Groupand the PHENIX Collaboration

Univ. of Tsukuba/RIKEN2013/06/23

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Heavy Flavor(c,b) in Heavy Ion CollisionsMainly created at initial hard scatteringTraverse and interact with the hot and dense

medium.Good probe to study hot and dense medium

Previous PHENIX HF result

- RAA is suppressed ( c,b -> e) - Non zero v2 ( c,b -> e )

Surprising result

But the result is mixture of c and b -Separating c and b is needed

PRL 98 172301

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η dependence of v1,v2,v3

v1 as function of η:STAR0-40%

AuAu 200GeV

Phys.Rev.Lett. 101 252301

η3

η

Phys.Rev. C77 054901

AuAu200GeV10-40%

NN2012:STAR

AuAu200GeV

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v2,v3 as function of η:STAR - v2:Blue data point　 - v3:Red data point - |η|<1v2,v3 Flat distribution

Silicon Vertex Detector (VTX)

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Silicon Vertex detector was installed from run 2011 -Physics Motivation ・ Measurement of heavy flavor -Detector design ・ Barrel Type & 4 layers Inner 2 layers : pixel detector Outer 2 layers : strip detector ・ Δφ~2π ・ |η|<1.2

VTX:|η|<1.2

MPC:3.1<|η|<3.7

BBC:3.0<|η|<3.9

CNT:|η|<0.35

SMD/ZDC η

dN/dη

1.2-1.2 5-5

VTX Track Reconstruction

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VTX

DC+PCRICH

TOF EMCAL

Central Arm

DcTrack

B3B2B1B0

VTX

VTX Standalone Tracking - VTX can reconstruct charged particle tracks (require more than 3 hits on VTX) - Low momentum resolution - |η|<2.0 - Measurement Primary Vertex

Central Arms + VTX tracking - Central Arms track is associated with the VTX clusters(charged particle hits) - High momentum resolution - |η|<0.35 - Measurement DCA

There are two types of tracking

Separating c and b using DCA

Lifetime (ct) D0 : 125 mm B0 : 464 mm

DCA

AuAuD

B

e

e

Side View of VTX

We know the shape of each component from PYHIA simulation. By simultaneous fitting of DCA distribution, each component can be

separated statistically.

D and B mesons travel before semi-leptonic decay to electron

Measure DCA to separate c and b components of heavy flavor spectra. DCA corresponds to the life time.

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b->e/(c->e+b->e) in pp collision

Separate b->e , c->eConsistent with previous PHENIX result and FONLL calculation 7

v2 、v3 and Event Plane resolution

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pT/η dependence of v2, v3 - CNT- SVX track |η|<0.35 - standalone track |η|<1.5 η dependence of event plane resolution - Spectator vs Participant EP correlation - Participant vs Participant EP correlation

Analysis Method : Event Plane Method

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Event Plane(The angle a lot of the particles are emitted in)The angle the particles are emitted in

x

y

Event Plane with elliptic moment

10BBC South/North/South + North

centrality[%]/10

0

0.1

CNT+VTX tracks(CNT tracks was associated with stand-alone track of VTX) orVTX standalone tracks

Track reconstruction

Event Plane measurement

η

BBC

Nor

th

BBC

Sou

th

-1.2 1.2-3.9 -3.0 3.0 3.9

φ2π

0VT

X

CNT

0

0.1

0.2

Analysis Method : Event Plane Method

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• v2 and v3 of charged hadron has reduced background by application of

DCA cut < 200um.

• v2 are consistent with previous measurements of p0 v2 in high pT region.

PHENIX

v2,v3: pT dependence (CNT+VTX tracks)

PHENIX• Extend to high pT region for v3.

• Good agreement with previous data in low pT region.

• A non-zero v3 is still observed in high pT

region.

v2:pT dependence(VTX standalone tracks)

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Comparison with previous PHENIX result (PRL107.252301) v2

using CNT tracks and v2 using VTX standalone tracks - Standalone tracks pT region is 0.25<pt<1[GeV/c]

Au+Au √SNN= 200GeV

Consistent with previous PHENIX previous result pT<1[GeV/c]

v2: η dependence(standalone tracks)

Comparison to PHOBOS v2

- PHOBOS : centrality 25-60%, pt> 0[GeV/c] - PHENIX : centrality 20-60%, 0.25<pt< 1[GeV/c]

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Au+Au √SNN= 200GeV

Consistent with PHOBOS result within systematic errorbar

Event Plane Resolution: η dependenceSVX 0.5η slice EP resolution : 12 EP |η|<3

EP resolution reflects amplitudes of vn in sub-events and their Multiplicity

layer0layer1

layer2layer3

8 9 10 11 127654321

0-3 -2 -1 1 2 3ηBBC

SMDSMDBBC

SVX EP ResolutionRaw EP Correlation

SMD/BBC EP Resolution

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EP Resolution :

Similar to v1 distributionDepend on SMD Plane: SMD S> SMD SN > SMD N

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Strong centrality dependenceAt η=0, Multiplicity is high. Triangular shapeNo EP selection dependence

EP Resolution :

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At Mid-rapidity , data points are minus value , - Momentum ConservationThe data points become plus value at the rapidity EP is

measured , - Non flow effect

EP Resolution :

η>0

η<0

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Similar to Psi2 Correlation using SMDThe data points become lager at the rapidity

EP is measured - Non flow Effect

EP Resolution :

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Similar to Psi2 Correlation – Symmetry distribution Weak Centrality dependence like v3

EP Resolution :

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Summary

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Heavy Flavor Separate c and b in pp collision

Event Plane resolution (SVX 0.5 slice) Psi1 vs Psi1 - Spectator vs Participant : similar to v1 、 Depend on SMD( SMD S > SMD SN > SMD N) - Participant vs Participant : momentum conservation , non flow Psi1 vs Psi2 - Spectator vs Participant : similar to v2 Psi2 vs Psi2 - Similar to Psi2 resolution using SMD, non flow Psi3 vs Psi3 - Similar to Psi2 resolution distribution

Charged Hadron v2 ,v3

pT dependence|η|<0.35 : Consistent with previous result pT dependence |η|<1.5 : Consistent with previous result below 1 [GeV/c] η dependence : Consistent with PHOBOS result

v2 :

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VTX 0.5-η slice

VTX cluster(charged particle hit)

Z

0

layer0

layer1

layer2

layer3Used clusters were in these region

was measured in this region(Δη=0.5)

BBC South BBC North

Δη=0.5

centrality[%]0 10050

Au+Au √SNN= 200GeV

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VTX 0.5-η slice

VTX cluster(charged particle hit)

centrality[%]0 10050

I divided VTX into 12 parts by 0.5η slice.

0-3.0 -2.0 -1.0 1.0 2.0 3.0layer0

layer1layer2

layer3

η

η coordinate 　

Au+Au √SNN= 200GeV

v2 :

layer0layer1

layer2layer3

8 9 10 11 127654321

0-3.0 -2.0 -1.0 1.0 2.0 3.0 ηI calculated correlation between BBC NS and these region. 23

VTX 0.5-η slice

VTX cluster(charged particle hit)

centrality[%]0 10050

Au+Au √SNN= 200GeV

v2 :

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VTX 0.5-η slice

VTX cluster(charged particle hit)

centrality[%]0 10050

0

centrality[%] 0

0.05

0.1

0.15-3.0 -2.0 -1.0 1.0 2.0 3.0

η

Au+Au √SNN= 200GeV

v2 :

v2:

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η dependence of v2 using cluster(charged particle hit) - no BG subtraction and no pt selection v2 around EP measurement region is higher than v2 in other region - Non flow effect is seen - Non flow effect seems to be asymmetry. We should separate Mid-rapidity side : Δη=1.5 , Forward rapidity side : Δη=1 　

η

EP measurement region(0.5<η<1)

Au+Au √SNN= 200GeVperformance plot

η

v2:

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0<|η|<0.5 0.5<|η|<1 1<|η|<1.5 1.5<|η|<2

Au+Au √SNN= 200GeV

v ２ using EP measured in other rapidity region( Black:η<0, Red:η>0) In other EP measurement regions, v2 distributions also look asymmetry.

performance plot

EP Resolution : BBC Psi2, Psi3

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EP Resolution : SMD Psi1, Psi2

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dN/dη