Browse

Search for exotic particles and measurement of Ξ*(1530)&Ξc(2470) Bf from Υ(1,2S) in Belle
Belle 실험에서의 exotic particle 연구와 Xi baryon의 Υ(1,2S)로 부터의 붕괴율 측정

DC Field Value Language
dc.contributor.advisor최선호-
dc.contributor.author김봉호-
dc.date.accessioned2017-07-14T00:56:42Z-
dc.date.available2017-07-14T00:56:42Z-
dc.date.issued2013-08-
dc.identifier.other000000012584-
dc.identifier.urihttps://hdl.handle.net/10371/121502-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 물리·천문학부 물리학 전공, 2013. 8. 최선호.-
dc.description.abstract기존 강입자(hadron)의 구성 쿼크(quark)수를 넘는 퀴크수로 이루어진 엑조틱바리온(exotic baryon)은 이른 양자색역학(Quantum Chromodynamics: QCD)에서부터 예측되어 왔다. 많은 실험들이 이루어졌지만 아직 엑조티바리온의 존재에 대한 확실한 결론이 나오지 않는 상황이다. 5개의 쿼크로 구성된 펜타쿼크(Pentaquark) 바리온은 2003년부터 실험이 전성기를 이루었지만 2009년에 존재의 부정과 함께 실험이 거의 사라졌다. 그러나 비슷한 시기에 6개의 쿼크로 구성된 에이치-다이바리온(H-dibaryon)에 대한 실험이 긍정적인 결과를 내었고 이는 엑조틱바리온 실험이 계속될 필요가 있음을 보여줬다.
이 논문에서는 이러한 엑조틱바리온 실험의 일환으로 웁실론(1,2에스)(Υ(1,2S)) 보토모늄(bottomonium) 메존(meson)으로부터 붕괴하는 -2 전하의 카이(Ξ5--) 펜타쿼크과 에이치-다이바리온을 찾아보았다. 더불어 1억200만개의 웁실론(1에스) 보토모늄 메존과 1억 5500만개의 웁실론(2에스) 보토모늄 메존으로부터 붕괴하는 바리온을 포함한 붕괴율(branching fraction B(〖Υ(1S)→Ξ ̅〗^(*0) (1530)X)=(3,23±0.15(stat)±0.26(syst))×〖10〗^(-3)), 그리고 바리온을 포함한 붕괴비율 B(Υ(1S)→Ξ_c^0 (2470)X)×B(Ξ_c^0 (2470)→Ξ^- π^+)=(3,42±0.34(stat)±0.15(syst))×〖10〗^(-3)) 측정결과를 보고한다. 모든 데이터는 케이이케이비 가속기(KEKB collider)의 벨 검출기(Belle detector)에서 모은 것이다.
-
dc.description.abstractThe possible baryons which has exotic quantum numbers have been predicted from the earliest days of QCD. Though several searches are done, theres still no confident answer. Pentaquark search was increased from 2003 and almost end at 2009 with denial of the existence. But silmilar years, Hdibaryon searches show some possibility and this shows exotic particle search is not dead. In here, i report searches of exotic particle candidates though we could not find any hint of existence.

I present results from searches for exotic multiquark baryon states, including the Ξ5-- pentaquark and the H-Dibaryon in inclusive Y(1, 2S) decays. In addition we report first measurements of the inclusive branching fraction B(Y(1S) → Ξ*0(1530) X) = (3.23 ± 0.02 (stat) ± 0.26 (syst)) × 10−3, and inclusive product branching fraction B(Y(1S) → Ξc(2470) X) × B(Ξc→Ξ−π+) = (3.42 ± 0.34 (stat) ± 0.15 (syst)) × 10−5, using data samples containing 102 million (1S) decays and 158 million (2S) collected in the Belle detector at the KEKB collider.
-
dc.description.tableofcontents1 Introduction 1
1.1 Basic concept 1
1.2 exotic particles 3
1.2.1 preview 3
1.2.2 penta-quark 4
1.2.3 H-dibaryon 7
1.2.4 State of these exotic candidate? 14
1.3 Inclusive decays of the Y(1S,2S) to baryon with S = − 2 15
2 KEKB Accelerator and Belle Detector 16
2.1 KEKB Accelerator 16
2.1.1 Feautres of KEKB 17
2.2 Belle Detector 18
2.2.1 Interaction region 18
2.2.2 EFC 19
2.2.3 SVD 20
2.2.4 CDC 22
2.2.5 ACC 32
2.2.6 TOF 35
2.2.7 ECL 38
2.2.8 KLM 42
3 Data analysis 47
3.1 Data samples with Hadron B(J) skim & MC samples 48
3.1.1 Number estimation for (1S) & (2S) data sample 48
3.1.2 Hadron B(J) skim 49
3.1.3 BELLE library 52
3.1.4 MC generation 52
3.2 Λ selection 54
3.3 Ξ−π selection 59
3.3.1 Ξ− selection 59
3.3.2 Ξ−π selection 64
3.3.3 data comparision 75
3.3.4 continuum-subtraction 82
3.4 ΛΛ selection 84
3.4.1 mc simulation 84
3.4.2 data comparision 89
3.4.3 efficiency and resolution estimation 94
3.5 Λpπ selection 97
3.5.1 mc simulation 97
3.5.2 data comparision 102
3.5.3 effieciency and resolution estimation 110
3.6 Ξ−p selection 111
3.6.1 mc simulation 111
3.6.2 efficiency and resolution estimation 113
4 Results & Discussion 115
4.1 Results for Ξ*0(1530) and Ξc(2470) production 115
4.1.1 B(Y(1S) → Ξ*0(1530) X) 115
4.1.2 B(Y(1S) → Ξc(2470) X) × B(Ξc→Ξ−π+) 117
4.1.3 B(Y(2S) → Ξ*0(1530) X) 118
4.1.4 B(Y(2S) → Ξc(2470) X) × B(Ξc→Ξ−π+) 119
4.2 Searching the 5 pentaquark 121
4.2.1 Opening the 5 blind box 121
4.2.2 Upper Limits for B(Y(1, 2S) →Ξ5X) × B(Ξ5 →Ξ−(π− (π+)) 121
4.3 Search for Y(1, 2S) → H X 126
4.3.1 Blind box open for Y(1, 2S) → HX
-
dc.description.tableofcontentsH→Ξ−p 126
4.3.2 Search for Y(1, 2S) → HX
-
dc.description.tableofcontentsH →ΛΛ 126
4.3.3 Search for Y(1, 2S) → HX
-
dc.description.tableofcontentsH →Λpπ− 131
4.3.4 Search for Y(1, 2S) → HX
-
dc.description.tableofcontentsH →Ξ−p 135
5 systematic uncertainties 137
5.1 Systematic error study for H → Λpπ−and H →ΛΛ channel 138
5.2 Systematic error study for H → Ξ−p channel 142
6 Conclusions 144
A Experimental search list 150
A.1 H-dibaryon searches 150
A.2 Penta-quark searches 152
-
dc.formatapplication/pdf-
dc.format.extent3521764 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoko-
dc.publisher서울대학교 대학원-
dc.subject주요어: 엑조틱-
dc.subject펜타쿼크-
dc.subject에이치-다이바리온-
dc.subject-
dc.subject붕괴율-
dc.subject.ddc523-
dc.titleSearch for exotic particles and measurement of Ξ*(1530)&Ξc(2470) Bf from Υ(1,2S) in Belle-
dc.title.alternativeBelle 실험에서의 exotic particle 연구와 Xi baryon의 Υ(1,2S)로 부터의 붕괴율 측정-
dc.typeThesis-
dc.description.degreeDoctor-
dc.citation.pagesxix, 152-
dc.contributor.affiliation자연과학대학 물리·천문학부(물리학전공)-
dc.date.awarded2013-08-
Appears in Collections:
College of Natural Sciences (자연과학대학)Dept. of Physics and Astronomy (물리·천문학부)Physics (물리학전공)Theses (Ph.D. / Sc.D._물리학전공)
Files in This Item:
  • mendeley

Items in S-Space are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse