Heavy Flavor and Charged Hadron Flow measurement using Silicon Vertex Detector at PHENIX Hiroshi Nakagomi for the SVX Group and the PHENIX Collaboration Univ. of Tsukuba/RIKEN 2013/06/23 1

Heavy Flavor(c,b) in Heavy Ion Collisions  Mainly created at initial hard scattering  Traverse and interact with the hot and dense medium. Good probe to study hot and dense medium  Previous PHENIX HF result - R AA is suppressed ( c,b -> e) - Non zero v 2 ( c,b -> e ) Surprising result But the result is mixture of c and b -Separating c and b is needed PRL

η dependence of v 1, v 2,v 3  v 1 as function of η:STAR 0-40% AuAu 200GeV Phys.Rev.Lett η 3 η Phys.Rev. C AuAu200GeV 10-40% NN2012:STAR AuAu200GeV 3  v 2,v 3 as function of η:STAR - v 2 :Blue data point - v 3 :Red data point - |η|<1v 2, v 3 Flat distribution

Silicon Vertex Detector (VTX) 4  Silicon Vertex detector was installed from run 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

VTX Track Reconstruction 5 VTX DC+PC RICH 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|< Measurement DCA There are two types of tracking

Separating c and b using DCA Lifetime (c  ) D 0 : 125  m B 0 : 464  m DCA Au D 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. 6

b->e/(c->e+b->e) in pp collision  Separate b->e, c->e  Consistent with previous PHENIX result and FONLL calculation 7

v 2 、 v 3 and Event Plane resolution 8  p T /η dependence of v 2, v 3 - CNT- SVX track |η|< 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 9 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

10 BBC South/North/South + North centrality[%]/ CNT+VTX tracks (CNT tracks was associated with stand-alone track of VTX) or VTX standalone tracks Track reconstruction Event Plane measurement η BBC North BBC South φ 2π 0 VTX CNT Analysis Method : Event Plane Method

v 2 and v 3 of charged hadron has reduced background by application of DCA cut < 200um. v 2 are consistent with previous measurements of  0 v 2 in high p T region. 11 PHENIX v 2,v 3 : p T dependence (CNT+VTX tracks) PHENIX Extend to high p T region for v 3. Good agreement with previous data in low p T region. A non-zero v 3 is still observed in high p T region.

v 2 :p T dependence(VTX standalone tracks) 12  Comparison with previous PHENIX result (PRL ) v 2 using CNT tracks and v 2 using VTX standalone tracks - Standalone tracks p T region is 0.25<pt<1[GeV/c] Au+Au √S NN = 200GeV Consistent with previous PHENIX previous result p T <1[GeV/c]

v 2 : η dependence(standalone tracks)  Comparison to PHOBOS v 2 - PHOBOS : centrality 25-60%, p t > 0[GeV/c] - PHENIX : centrality 20-60%, 0.25<p t < 1[GeV/c] 13 Au+Au √S NN = 200GeV Consistent with PHOBOS result within systematic errorbar

Event Plane Resolution: η dependence SVX 0.5η slice EP resolution : 12 EP |η|<3  EP resolution reflects amplitudes of v n in sub-events and their Multiplicity layer0 layer1 layer2 layer η BBC SMD BBC SVX EP Resolution Raw EP Correlation SMD/BBC EP Resolution 14

EP Resolution : Similar to v 1 distribution Depend on SMD Plane: SMD S> SMD SN > SMD N 15

Strong centrality dependence At η=0, Multiplicity is high. Triangular shape No EP selection dependence EP Resolution : 16

At Mid-rapidity, data points are minus value, - Momentum Conservation The data points become plus value at the rapidity EP is measured, - Non flow effect EP Resolution : η>0 η<0 17

Similar to Psi2 Correlation using SMD The data points become lager at the rapidity EP is measured - Non flow Effect EP Resolution : 18

Similar to Psi2 Correlation – Symmetry distribution Weak Centrality dependence like v3 EP Resolution : 19

Summary 20  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 v 2, v 3 p T dependence|η|<0.35 : Consistent with previous result p T dependence |η|<1.5 : Consistent with previous result below 1 [GeV/c] η dependence : Consistent with PHOBOS result

v 2 : 21 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[%] Au+Au √S NN = 200GeV

22 VTX 0.5-η slice VTX cluster(charged particle hit) centrality[%] I divided VTX into 12 parts by 0.5η slice layer0 layer1 layer2 layer3 η η coordinate Au+Au √S NN = 200GeV v 2 :

layer0 layer1 layer2 layer η I calculated correlation between BBC NS and these region. 23 VTX 0.5-η slice VTX cluster(charged particle hit) centrality[%] Au+Au √S NN = 200GeV v 2 :

24 VTX 0.5-η slice VTX cluster(charged particle hit) centrality[%] centrality[%] η Au+Au √S NN = 200GeV v 2 :

v2:v2: 25  η dependence of v 2 using cluster(charged particle hit) - no BG subtraction and no p t selection  v 2 around EP measurement region is higher than v 2 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 √S NN = 200GeV performance plot

η v2:v2: 26 0<|η|<0.50.5<|η|<1 1<|η|< <|η|<2 Au+Au √S NN = 200GeV  v ２ using EP measured in other rapidity region( Black:η 0) In other EP measurement regions, v 2 distributions also look asymmetry. performance plot

EP Resolution : BBC Psi2, Psi3 27

EP Resolution : SMD Psi1, Psi2 28

29 dN/dη