heavy flavor and charged hadron flow measurement using silicon vertex detector at phenix hiroshi...

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:STAR

0-40%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

B3

B2

B1

B0

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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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

layer3

Used clusters were in these region

was measured in this region(Δη=0.5)

BBC South BBC North

Δη=0.5

centrality[%]0 10050


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VTX 0.5-η slice



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 　


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




v2 :

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VTX 0.5-η slice



0

centrality[%] 0

0.05

0.1

0.15-3.0 -2.0 -1.0 1.0 2.0 3.0

η


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


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

heavy flavor and charged hadron flow measurement using silicon vertex detector at phenix hiroshi...

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