J/psi suppression with respect to the reaction plane in Au+Au collisions at sqrt{sNN}=200 GeV by the PHENIX detector
- 주제(키워드) J/psi , suppression , QGP , reaction plane
- 발행기관 고려대학교 대학원
- 지도교수 심광숙
- 발행년도 2011
- 학위수여년월 2011. 2
- 학위구분 박사
- 학과 일반대학원 물리학과
- 세부전공 원자핵물리학 전공
- 원문페이지 173 p
- 실제URI http://www.dcollection.net/handler/korea/000000024495
- 본문언어 영어
- 제출원본 000045640773
초록/요약
The J/psi production by the PHENIX experiment was measured with the full statistic of 2007 Au+Au collisions at sqrt{sNN} = 200 GeV at RHIC. The statistic has been increased by a factor of 3 (813 ub^{−1}) compared to previous 2004 data set, thus allowing a more precise measurement of the J/psi production. J/psi particles were identified with the dimuon decay channels at forward rapidity (1.2 < |y| < 2.2). A suppression of J/psi relative to the binary scaling of p+p collision was observed for central Au+Au collisions and consistent with previous 2004 results. And during the 2007 data taking, PHENIX experiment benefited from the addition of a new detector which improves the reaction plane resolution. It allows us to measure the reaction plane dependence of J/psi production such as the J/psi elliptic flow v2 and nuclear modification factor R_{AA}(pT) with respect to the reaction plane more precisely. Various methods were applied to measure the J/psi elliptic flow v2 and nuclear modification factor R_{AA}(pT) with respect to the reaction plane and the associated systematic uncertainty was estimated. Since those results would be affected by the J/psi production mechanisms in the hot nuclear matters, J/psi v2(pT) was compared with several theoretical models.
more목차
1 Introduction 1
2 Search for QGP 5
2.1 Bulk properties . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.1 Hydrodynamic model . . . . . . . . . . . . . . . . . . . 6
2.1.2 Statistical model . . . . . . . . . . . . . . . . . . . . . 8
2.1.3 Elliptic flow . . . . . . . . . . . . . . . . . . . . . . . . 9
2.1.4 Jet quenching and parton energy loss . . . . . . . . . . 12
2.1.5 Reaction plane dependence of energy loss . . . . . . . . 15
2.2 Hadronization . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2.1 Recombination model . . . . . . . . . . . . . . . . . . . 18
2.2.2 Fragmentation . . . . . . . . . . . . . . . . . . . . . . . 20
3 J/psi production 23
3.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.2 Charm quark production . . . . . . . . . . . . . . . . . . . . . 28
3.3 J/psi production mechanisms . . . . . . . . . . . . . . . . . . . 30
3.3.1 Gluon interactions . . . . . . . . . . . . . . . . . . . . 30
3.3.2 Quark coalescence . . . . . . . . . . . . . . . . . . . . . 33
3.4 J/psi measurements in PHENIX . . . . . . . . . . . . . . . . . 37
3.4.1 J/psi productoin in p+p and d+Au collisions . . . . . . 37
3.4.2 J/psi production in Au+Au and Cu+Cu collisions . . . 37
4 Experimental Setup 41
4.1 The overview of RHIC . . . . . . . . . . . . . . . . . . . . . . 41
4.2 PHENIX detector . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.2.1 Global detectors . . . . . . . . . . . . . . . . . . . . . . 46
4.2.2 Central arm detectors . . . . . . . . . . . . . . . . . . 49
4.2.3 Muon arm detectors . . . . . . . . . . . . . . . . . . . 50
4.2.4 Reaction plane determination detectors . . . . . . . . . 59
4.2.5 Detector upgrade . . . . . . . . . . . . . . . . . . . . . 63
4.3 Trigger system . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.3.1 Lvl1 trigger . . . . . . . . . . . . . . . . . . . . . . . . 70
4.3.2 Lvl2 trigger . . . . . . . . . . . . . . . . . . . . . . . . 71
4.4 Data Acquisition System and reconstruction . . . . . . . . . . 73
4.4.1 ONCS . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
4.4.2 Off-Line . . . . . . . . . . . . . . . . . . . . . . . . . . 76
5 Data Analysis 78
5.1 Good run selection . . . . . . . . . . . . . . . . . . . . . . . . 80
5.2 Analysis cuts . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
5.2.1 Quality cuts . . . . . . . . . . . . . . . . . . . . . . . . 81
5.2.2 Comparison with real and simulation results . . . . . . 82
5.3 Signal extraction . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.3.1 Event mixing . . . . . . . . . . . . . . . . . . . . . . . 85
5.3.2 J/psi yield measurement . . . . . . . . . . . . . . . . . . 85
5.3.3 J/psi yield as a function of centrality . . . . . . . . . . . 88
5.3.4 J/psi yield as a function of pT . . . . . . . . . . . . . . 88
5.3.5 J/psi yield with respect to the reaction plane . . . . . . 96
5.4 Reaction plane resolution . . . . . . . . . . . . . . . . . . . . . 100
5.5 Elliptic flow measurement . . . . . . . . . . . . . . . . . . . . 103
5.5.1 Fitting method . . . . . . . . . . . . . . . . . . . . . . 103
5.5.2 In-Out ratio method . . . . . . . . . . . . . . . . . . . 106
5.5.3 Invariant mass fit method . . . . . . . . . . . . . . . . 107
5.6 Embedding simulation . . . . . . . . . . . . . . . . . . . . . . 109
5.6.1 Response . . . . . . . . . . . . . . . . . . . . . . . . . 109
5.6.2 Embedding and reconstruction . . . . . . . . . . . . . . 110
5.6.3 Acc*Eff as a function of centrality . . . . . . . . . . . . 110
5.6.4 Acc*Eff as a function of centrality and pT . . . . . . . 112
5.6.5 Acc*Eff as a function of pT and delta_phi . . . . . . . . . . . 114
6 Results 116
6.1 J/psi invariant yield . . . . . . . . . . . . . . . . . . . . . . . . 116
6.1.1 Principle . . . . . . . . . . . . . . . . . . . . . . . . . . 116
6.1.2 Error calculation . . . . . . . . . . . . . . . . . . . . . 117
6.1.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
6.2 J/psi nuclear modification factor, R_{AA} . . . . . . . . . . . . . . 124
6.2.1 Principle . . . . . . . . . . . . . . . . . . . . . . . . . . 124
6.2.2 Systematic error . . . . . . . . . . . . . . . . . . . . . 126
6.2.3 Both arm averaged R_{AA} . . . . . . . . . . . . . . . . . 126
6.2.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
6.3 J/psi elliptic flow . . . . . . . . . . . . . . . . . . . . . . . . . . 140
6.3.1 Result . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
6.3.2 Comparison with models . . . . . . . . . . . . . . . . . 142
6.3.3 Comparison with the preliminary results . . . . . . . . 144
7 Conclusions 145
Bibliography 147
