1 / 10

RHIC – PHENIX 実験における単電子の測定 Single Electron Measurement at RHIC – PHENIX

RHIC – PHENIX 実験における単電子の測定 Single Electron Measurement at RHIC – PHENIX. T. Hachiya Hiroshima Univ. For the PHENIX collaboration. Motivation. Charm is produced through mainly gluon-gluon fusion in heavy ion collisions Sensitive to gluon density in initial stage of the collisions

telyn
Download Presentation

RHIC – PHENIX 実験における単電子の測定 Single Electron Measurement at RHIC – PHENIX

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. RHIC–PHENIX実験における単電子の測定Single Electron Measurement at RHIC–PHENIX T. Hachiya Hiroshima Univ. For the PHENIX collaboration

  2. Motivation • Charm is produced through mainly gluon-gluon fusion • in heavy ion collisions • Sensitive to gluon density in initial stage of the collisions • Charm propagate through hot and dense medium created • in the collisions • Energy loss of charms via gluon radiation can be seen. • (PHENIX observed high pT suppressions in hadron measurements) • Charm measurements bring us an important baseline of J/ • measurement • Charm Measurement • Measure leptons from • semi-leptonic decay of charm. JPS meeting at Miyazaki

  3. PC3 PC2 RICH PC1 DC All charged tracks Mirror e+ e± real. X Net e± BG EMCalorimeter Cherenkov light in RICH Electron Measurement • Electrons are measured by • DC→PC1→RICH→EMCal • Electron Identification : • Cherenkov light in RICH • Number of Hit PMT • Ring shape • Energy – Momentum matching JPS meeting at Miyazaki

  4. e+ e- Photon Converter Photon Converter Method Source of Electrons • Photonic source • Photon conversion, Dalitz decay… • Non-photonic source • Charm and Beauty decay Photon Converter • 1.7 % radiation length (brass) • The converter can increase electrons only from photonic source by a fixed factor • By comparing the data W and W/O the converter, electrons from non- photonic and photonic source can be separated.  Difficulty • Need to adjust acceptance between real data and simulation. • Amount of material in simulation need to be same with that in real data. JPS meeting at Miyazaki

  5. Ratio of pT in Real Data and Simulation Real data Sim Sim +４．３% Sim –４．３% pT of e[GeV/c] Comparison of Conv/No Conv Ratio in Real Data and Simulation • If there is no non-photonic source, real data should agree with simulation. • The ratio in simulation looks gradually increasing. It is different with that in real data.  Existence of non-photonic source. • Different amount of material between real data and simulation is studied. (explained in next page) JPS meeting at Miyazaki

  6. Mee in conv. Run Mee in no-conv. run Mee in real data Mee[GeV] NConverter : Mee:60-100[MeV] NInner : Mee:0-40[MeV] Mee in simulation Mee[GeV] Comparison of Amount of Material in Real data and Simulation Assumption : thickness of the converter in simulation is same that in real data. • Mee distribution is normalized by Nevent. • Calculate the Ratio( RM ) of Mee(inner) and Mee(converter) • Then, compare RM in real data and simulation. • Difference between real data and simulation is 0.8%4.3%. Conclusion: JPS meeting at Miyazaki

  7. pT[GeV/c] Raw pT distributions Inclusive e Non-Photonic e Photonic e pT[GeV/c] Separate Non-Photonic and Photonic Electrons Ratio of pT in Real Data and Simulation • Raw pT distribution of both photonic and non-photonic electrons are obtained by following method (converter subtraction). JPS meeting at Miyazaki

  8. Corrected Pt spectra of non-photonic electrons Au+Au @sNN= 200GeV, Min. Bias QM02 : PHENIX PRELIMINALY Current Analysis: Work in Progress • Nevents: • 2.5M in no conv. Run • 2.2M in conv. run • Present analysis is consistent with QM02 Preliminary result within errors. • Systematic error is much reduced. JPS meeting at Miyazaki

  9. 10-20% Min. Bias 10-20% 0-10% 1/2pT·dN/dydpT 1/2pT·dN/dydpT 1/2pT·dN/dydpT pT [GeV/c] pT [GeV/c] pT [GeV/c] 20-40% 60-92% 40-60% Data Charm Beauty Combined 1/2pT·dN/dydpT 1/2pT·dN/dydpT 1/2pT·dN/dydpT pT [GeV/c] pT [GeV/c] pT [GeV/c] Centrality Dependence of Non-Photonic Electrons Work in Progress • PYTHIA calculation is scaled with number of binary collisions. • Well described for all centralities. JPS meeting at Miyazaki

  10. Summary • Conversion subtraction method is refined • Difference of amount of material in real and simulation is 0.8%4.3% • Systematic error is much reduced. • Corrected pT spectra of non-photonic electrons are measured in Au+Au collision at sNN= 200GeV. • The Spectra are compared with PYTHIA calculation. • Consistent with electrons from charm and beauty decay. • Described by binary scaling. • Electron measurement by the converter method is very close to final -> Next meeting. Next Step • Eta and Kaon should be taken into account. • The other method to measure high pT region. JPS meeting at Miyazaki

More Related