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Heavy Flavor and Charged Hadron Flow measurement using Silicon Vertex Detector at PHENIX

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. Heavy Flavor( c,b ) in Heavy Ion Collisions. Mainly created at initial hard scattering

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Heavy Flavor and Charged Hadron Flow measurement using Silicon Vertex Detector at PHENIX

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  1. 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

  2. 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 PRL 98 172301 • Previous PHENIX HF result • Surprising result - RAA is suppressed ( c,b -> e) - Non zero v2 ( c,b -> e ) • But the result is mixture of c and b -Separating c and b is needed

  3. η dependence of v1,v2,v3 Phys.Rev. C77 054901 AuAu200GeV Phys.Rev.Lett. 101 252301 • v1 as function of η:STAR 10-40% AuAu 200GeV • v2,v3 as function of η:STAR • - v2:Blue data point • - v3:Red data point • - |η|<1v2,v3 Flat distribution 0-40% η η NN2012:STAR AuAu200GeV 3

  4. Silicon Vertex Detector (VTX) • 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 dN/dη CNT:|η|<0.35 VTX:|η|<1.2 MPC:3.1<|η|<3.7 BBC:3.0<|η|<3.9 SMD/ZDC η 5 -1.2 1.2 -5

  5. VTX Track Reconstruction There are two types of tracking 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 B3 B2 B1 VTX B0 Central Arm DcTrack DC+PC • Central Arms + VTX tracking - Central Arms track is associated with the VTX clusters(charged particle hits) - High momentum resolution - |η|<0.35 - Measurement DCA RICH TOF EMCAL

  6. Separating c and b using DCA • Measure DCA to separate c and b components of heavy flavor spectra. DCA corresponds to the life time. • D and B mesons travel before semi-leptonic decay to electron e Side View of VTX Lifetime (ct) D0 : 125 mm B0 : 464 mm DCA D Au Au B e • We know the shape of each component from PYHIA simulation. • By simultaneous fitting of DCA distribution, each component can be separated statistically.

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

  8. v2、v3 andEvent Plane resolution • 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

  9. Analysis Method : Event PlaneMethod y Event Plane(The angle a lot of the particles are emitted in) x The angle the particles are emitted in Event Plane with elliptic moment

  10. Analysis Method : Event PlaneMethod φ 2π 0.2 0.1 0.1 0 η 1.2 3.0 3.9 -1.2 -3.0 -3.9 0 CNT+VTX tracks (CNT tracks was associated with stand-alone track of VTX) or VTX standalone tracks 0 Track reconstruction centrality[%]/10 BBC North BBC South VTX CNT Event Plane measurement BBC South/North/South + North

  11. v2,v3: pT dependence (CNT+VTX tracks) PHENIX • v2 and v3 of charged hadron has reduced background by application of • DCA cut < 200um. • v2are consistent with previous measurements of p0 v2 in high pT region. • Extend to high pTregion for v3. • Good agreement with previous data in low pT region. • A non-zero v3 is still observed in high pT region. PHENIX

  12. v2:pT dependence(VTX standalone tracks) Au+Au √SNN= 200GeV • 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] Consistent with previous PHENIX previous result pT<1[GeV/c]

  13. 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] Au+Au √SNN= 200GeV Consistent with PHOBOS result within systematic errorbar

  14. Event Plane Resolution: η dependence • SVX 0.5η slice EP resolution : 12 EP |η|<3 BBC BBC Raw EP Correlation SMD SMD SVX EP Resolution 2 3 7 8 12 1 4 5 6 9 10 11 SMD/BBC EP Resolution layer3 η • EP resolution reflects amplitudes of vnin sub-events and their Multiplicity layer2 layer1 -3 -2 -1 1 3 2 0 layer0

  15. EP Resolution : • Similar to v1 distribution • Depend on SMD Plane: SMD S> SMD SN > SMD N

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

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

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

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

  20. Summary • Heavy Flavor • Separate c and b in pp collision • Charged Hadron v2 ,v3 • pTdependence|η|<0.35 : Consistent with previous result • pTdependence |η|<1.5 : Consistent with previous result below 1 [GeV/c] • η dependence : Consistent with PHOBOS result • EventPlane 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

  21. v2 : Au+Au √SNN= 200GeV layer3 layer2 layer1 VTXcluster(charged particle hit) layer0 100 0 50 VTX 0.5-η slice centrality[%] Δη=0.5 Z was measured in this region(Δη=0.5) 0 Used clusters were in these region BBC South BBC North

  22. v2 : Au+Au √SNN= 200GeV VTXcluster(charged particle hit) 100 0 50 VTX 0.5-η slice centrality[%] I divided VTX into 12 parts by 0.5η slice. η coordinate layer3 layer2 -1.0 -2.0 3.0 1.0 η -3.0 2.0 0 layer1 layer0

  23. v2 : Au+Au √SNN= 200GeV VTXcluster(charged particle hit) 100 0 50 VTX 0.5-η slice centrality[%] 2 3 7 8 12 1 4 5 6 9 10 11 layer3 layer2 η layer1 -3.0 -1.0 1.0 -2.0 3.0 2.0 0 layer0 I calculated correlation between BBC NS and these region.

  24. v2 : Au+Au √SNN= 200GeV VTXcluster(charged particle hit) 100 0 50 VTX 0.5-η slice centrality[%] η -3.0 -2.0 2.0 -1.0 0 1.0 3.0 0.15 0.1 0.05 0 centrality[%]

  25. v2: • η dependence of v2 usingcluster(charged particle hit) - no BGsubtraction and no pt selection EP measurement region(0.5<η<1) performance plot Au+Au √SNN= 200GeV η • v2 around EP measurement region is higher than v2 in other region - Non floweffect is seen - Non flow effect seems to be asymmetry. We should separate Mid-rapidityside : Δη=1.5 , Forward rapidityside : Δη=1

  26. v2: 0<|η|<0.5 0.5<|η|<1 1<|η|<1.5 1.5<|η|<2 Au+Au √SNN= 200GeV performance plot η • v２using EP measured in other rapidity region( Black:η<0, Red:η>0) In other EP measurement regions, v2 distributions also look asymmetry.

  27. EP Resolution : BBC Psi2, Psi3

  28. EP Resolution : SMD Psi1, Psi2

  29. dN/dη

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