Non-photonic electron yields in p+p collisions at 200 GeV with reduced detector material in STAR

TAR Non-photonic electron yields in p+p collisions at 200 Gev with reduced detector material in Star > Introduction and motivation Electron identification Photonic background Current status and future plan Summary 2008 F Jin for star collaboration Shanghai Institute of Applied Physics, CAS BROOKHAUEN NATIONAL LABORATORY e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin Non-photonic electron yields in p+p collisions at 200 GeV with reduced detector material in STAR ➢ Introduction and motivation ➢ Electron identification ➢ Photonic background ➢ Current status and future plan ➢ Summary F. Jin for STAR Collaboration Shanghai Institute of Applied Physics, CAS 1

TAR Introduction and motivation Open charm K Total charm cross section 1)test perturbative QCd prediction 2)input the cross section to do model calculation -Radial and elliptic flow d)bulk Qcd medium properties density, the drag coefficient and viscosity 2)test light flavor thermalization -Energy loss D K T e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin 2 Open charm –Total charm cross section 1) test perturbative QCD prediction 2) input the cross section to do model calculation –Radial and elliptic flow 1) bulk QCD medium properties ( density, the drag coefficient and viscosity ) 2) test light flavor thermalization –Energy loss Introduction and Motivation

TAR Current status of charm measurement STAR (nucl-ex/0607012 400F STAR Preliminary O STAR D+H+e(Au+Au) STAR(PRL 94(2005)062301). exP/GFONLL STAR D+e(d+Au) 口 STAR D(Cu+Cu) PHENIX (hep-ex/0609010) △ PHENIX e(Au+Au) HENIX e(p+p) PHENIXμ(p+p) 3200 8 sys. error Color dipole 100 HSD PYTHIA 回图 Rapidity y STAR: Larger acceptance PhEnIX. Lower material STAR removed svt and ssd in run 8, low material (0.55%Xo) run to try to address the observed 0246810 discrepancy between STAR and p(EviC PHENIX e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin 3 STAR: Larger acceptance PHENIX: Lower material STAR removed SVT and SSD in run 8, low material (~0.55%X0 ) run to try to address the observed discrepancy between STAR and PHENIX. Current status of charm measurement

TAR STAR-TOF STAR Detector Data sam ple in Run vil: 口 5 trays out of 120 trays lme t Coverage:-190% TOF-TOF. e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin 4 ➢ 5 trays out of 120 trays ➢ Coverage: -190% STAR-TOF

TAR Event and track selection 1) Ensure good TOF hits delta Y <1.5(cm) 2)TOF acceptance 1<n<0 150 Ensure rapidity distribution o 100 electron similar as that of pion 0.6<y<0 4)Ensure good primary track VAVPD)-VA(TPC)K<6( cm) .100 E 0900 50100150200 Vz from VPD (cm) e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin 5 1) Ensure good TOF hits |deltaY|<1.5(cm) 2) TOF acceptance 10 3) Ensure rapidity distribution of electron similar as that of pion 0.6<y<0 4) Ensure good primary track | Vz(VPD) – Vz(TPC) |<6(cm) Event and track selection

TAR eandπ Identification dEx vsp I dEdxvspt noE Entries 1 RMsx0357550 invBeta ineTa 1/B-11<0.03RMsy Entries 5183703 anx07431 苔06 any 1.073 1.8 RMsx0.4041 RMS y 0.1285 1.6 STAR Preliminary pure n STAR Preliminary no|<3 5 0.8 p(Evic 0,4 electron selection (TOF PID cut βB-1|<0.03 STAR Preliminary P( Evic e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin 6 | 1/ – 1 | < 0.03 electron selection (TOF PID cut) e and  Identification

TAR Yields extraction 0. 25 p(Gev/c) 0.5<p.Gev/c)<0.55 234353土0247030 slop:3231610522148 pure r mean.385051:0000143 ra200345796:0000107 STAR Preliminary STAR Preliminary Log,(de/d×) keV/cm Log, (de/dx)[keV/cm] k mean:027701136 05≤p(Gevc)<0.55 Constan354251:133798 1253:2.749005 STAR Preliminary STAR Preliminary 1000 Log, (de/dx)[keV/cm e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin 7 e  Yields extraction e e

TAR Yields check at higher pr wT1.64pIGeVics20 8. W/o EMC with EMc cf 1.6<p,GeVc)2.0 0.0345449:0.000292 k mean: 037847 k mean:0.350420000057 STAR Preliminary STAR Preliminary Log, (de/dx)[ke V/cm Log(de/dx)[ke V/cm LEMCEvSp」 RMsX0.5307 EMC energy cut make sure there are really electrons STAR Preliminary e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin 8 EMC energy cut make sure there are really electrons Yields check at higher pT with EMC cut w/o EMC cut

TAR Inclusive electron decomposition Three components of inclusive electron heavy-flavor decay(c, b) photonic background electron ☆ Dalitz decay of light mesons(π0,netc) gamma conversions other background electron 令Ks3 decay dielectron decays of vector mesons Photonic background has to be removed or subtracted e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin 9 Three components of inclusive electron: ➢ heavy-flavor decay (c,b) ➢ photonic background electron ❖ Dalitz decay of light mesons (     etc) ❖ gamma conversions ➢ other background electron ❖ Ke3 decay ❖ dielectron decays of vector mesons Photonic background has to be removed or subtracted Inclusive electron decomposition

TAR Reject gamma converted at high radius rDecayVertex (rDecayVertex<220) ht 25000FoBeampipe 0.29% radiation length 200。‖wap:014% o radiation length Air: 0. 1% radiation lend 15000 8 IFC: 0.36%radiation length B且 10000 STAR Preliminary 5000 TPC gas signed DCA for e+-(0.6<p <0.7 GeVic epto60070 92460°8010012014016010200240 igned dca for e+vs pt STAR Preliminary 5455 Rejection electron from gamma converted at IFC and TPc gas p (GeV/c) e Jin

-------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- F. Jin 10 Rejection electron from gamma converted at IFC and TPC gas Beampipe 0.29% radiation length wrap: 0.14% radiation length Air: 0.1% radiation length IFC: 0.36% radiation length Reject gamma converted at high radius Beam pipe TPC Inner Field Cage TPC gas