Tau Neutrino Appearance via Neutrino Oscillations in Atmospheric ...

More documents

Recommendations

Info

9Figure 1.3: A schematic view of the atmospheric neutrino production. Cosmicrays hit the atmosphere of the Earth isotropically, and neutrinos are produced.Atmospheric neutrinos travel from 15 km to 13,000 km before reaching thesurface of the earth.is defined to be the angle between the neutrino direction and a line perpendicularto the ground. The cosine of a zenith angle, cosθ = −1 corresponds tothe upward-going direction, cosθ = 0 to the horizontal direction, and cosθ =+1 to the downward-going direction. Further details of atmospheric neutrinosare described in Chapter 4.1.4.2 Neutrino Oscillation ExperimentsThe first atmospheric neutrino experiments were two water Cherenkov experiments,Irvine-Michigan-Brookhaven (IMB) [22, 23] and Kamiokande [24,25]. Although their primary scientific goals were to search for proton decay
10Table 1.2: List of the flavor ratio R(µ/e) measured by various experiments.Experiment Method Exposure Flavor Ratio(kt·year) R(µ/e)7.7 0.54 ± 0.05 ± 0.012 (Sub-GeV)IMB Water Cherenkov2.1 1.40 +0.41−0.30 ± 0.3 (Multi-GeV)7.7 0.60 +0.06−0.05 ± 0.05 (Sub-GeV)Kamiokande Water Cherenkov8.2 0.57 +0.08−0.07 ± 0.07 (Multi-GeV)NUSEX Iron Calorimeter 0.74 0.96 +0.32−0.28Fréjus Iron Calorimeter 1.56 1.00 ± 0.15 ± 0.08Soudan-2 Iron Calorimeter 5.1 0.68 ± 0.11 ± 0.06Super-K Water Cherenkov92 0.658 ± 0.016 ± 0.05 (Sub-GeV)92 0.702 +0.032−0.030 ± 0.101 (Multi-GeV)and the atmospheric neutrinos were found to be their main “backgrounds”,these backgrounds quickly became a topic of interest to study. Both experimentsfound the measured flavor ratio that was different from two. In practice,they measured the double ratio R of the observed flavor ratio (N Data ) to theexpected ratio (N MC ), to cancel the detector systematics and the uncertaintiesin the flux calculations, where the uncertainty in the absolute atmosphericneutrino flux is about 20 % and the error in the flavor ratio is expected to bewithin 5 %. The double ratio R is defined as :R(µ/e) ≡ (N µ /N e ) Data /(N µ /N e ) MC (1.15)where the ratio should be unity without oscillations. Both IMB and Kamiokandeexperiments measured R that was much less than unity as listed in Table 1.2.This became the “atmospheric neutrino anomaly” in the 1980’s and was interpretedas a possible indication for neutrino oscillations. Later experiments,NUSEX [26] and Frejus [27] using iron calorimeters, have reported no deviationfrom unity but using smaller data samples. However, Soudan 2,also an iron tracking calorimeter, measured smaller flavor ratio with higherstatistics later [28, 29]. A successor of Kamiokande, Super-Kamiokande, alsomeasured smaller flavor ratio with much larger data sample [41, 42]. Table1.2 lists the flavor ratios measured by various experiments. In additionto the flavor ratio, Kamiokande measured a zenith angle dependenceof R [30]. Using upward-going muons induced by atmospheric neutrinos,Kamiokande [31], Soudan 2 [34], and MACRO (composed of liquid scintillationcounters) [32, 33] found the zenith angle dependent deficit of muon
Page 1 and 2: Tau Neutrino Appearance via Neutrin
Page 3 and 4: Abstract of the DissertationTau Neu
Page 5 and 6: ContentsList of FiguresList of Tabl
Page 7 and 8: 6 Event Reconstruction 966.1 Vertex
Page 9 and 10: List of Figures1.1 Feynman diagrams
Page 11 and 12: 6.7 PID likelihood distributions fo
Page 13 and 14: AcknowledgementsAfter spending six
Page 15 and 16: I would like to thank administrativ
Page 17 and 18: 2and obey the exclusion principle a
Page 19 and 20: 4Table 1.1: Table of elementary par
Page 21 and 22: 6then, |ν α (t)〉 can be express
Page 23: 8As described in the next section,
Page 27 and 28: 12much smaller than the unity with
Page 29 and 30: 14Data/Prediction (null oscillation
Page 31 and 32: Figure 2.1: The location of Super-K
Page 33 and 34: Figure 2.2: An overview of the Supe
Page 35 and 36: 202.1.1 Cherenkov RadiationThe prim
Page 37 and 38: 22Figure 2.5: The layout of the PMT
Page 39 and 40: 24< φ 520photosensitive area > φ
Page 41 and 42: 26Quantum efficiency0.20.10300 400
Page 43 and 44: 282.3.2 Outer Detector PMTThe OD ph
Page 45 and 46: 30CARTRIDGEPOLISHERUVSTERILIZERVACU
Page 47 and 48: 32system is shown in Figure 2.13. T
Page 49 and 50: 34A block diagram of the ATM board
Page 51 and 52: 3620-inch PMTSCHATMx 24020-inch PMT
Page 53 and 54: 38Super−Kamiokande Outer Detector
Page 55 and 56: 402.6.4 Flash ADCAs a part of the S
Page 57 and 58: 42UV filter ND filterXe Flash LampO
Page 59 and 60: 44Number of PMTs in Each Bin1400120
Page 61 and 62: 46ND filterTriggerPMTDyeN2 LaserDif
Page 63 and 64: 485432Timing Resolution (nsec)10543
Page 65 and 66: 50Optical FiberLASER337nmTop371nm40
Page 67 and 68: 52Light scattering measurementatten
Page 69 and 70: 54neutrino analyses, such an estima
Page 71 and 72: 56Number of events14012010080604020
Page 73 and 74: 58momentum/range (MeV/cm)432DATAM.C
Page 75 and 76:
60µ momentum/trackelectron momentu
Page 77 and 78:
theoretical groups such as Honda fl
Page 79 and 80:
640Zenith angle of arrival directio
Page 81 and 82:
66Flux×E ν2(m -2 sec -1 sr -1 GeV
Page 83 and 84:
684% [105]. The flux of atmospheric
Page 85 and 86:
70where G E and G M are the electri
Page 87 and 88:
72resonance), M j is the mass of th
Page 89 and 90:
74σ (10 -38 cm 2 )0.25 (a) νp →
Page 91 and 92:
761.5(a) ν µN → µ - XIHEP-JINR
Page 93 and 94:
7821.751.5ν 16 O → l ± 16 O π
Page 95 and 96:
80ing experiments [158, 159, 160].
Page 97 and 98:
82shown in Figure 3.5. The timing o
Page 99 and 100:
8410.8ν τν µν eν - τν - µ
Page 101 and 102:
86Chapter 5Data ReductionThe Super-
Page 103 and 104:
88and exit the ID. The neutrino ene
Page 105 and 106:
90• NHITA 800 ≤ 50The number of
Page 107 and 108:
92• The distance between the cabl
Page 109 and 110:
94Coincidence muonsThe remaining co
Page 111 and 112:
96Chapter 6Event ReconstructionThe
Page 113 and 114:
9842 deg. ring(possible center)hit
Page 115 and 116:
100Number of events450400350Single-
Page 117 and 118:
102by muons or charged pions and ha
Page 119 and 120:
104Number of eventsNumber of events
Page 121 and 122:
106the changes in the vertex positi
Page 123 and 124:
108flux. This is because most of ν
Page 125 and 126:
110NUM 14RUN 999999SUBRUN 99EVENT 2
Page 127 and 128:
112expected to be upward-going.Base
Page 129 and 130:
114150100500(a)10 2 (b)1013.5 4 4.5
Page 131 and 132:
116SK-I Multi-GeV MCSK-II Multi-GeV
Page 133 and 134:
118Number of Events9080706050403020
Page 135 and 136:
120Table 7.5: Fraction of neutrino
Page 137 and 138:
122Number of Events604020TAU+BKGBKG
Page 139 and 140:
124100SK-ITAU+BKGBKGDATA6050SK-IITA
Page 141 and 142:
126• Up/down ratio : (For the obs
Page 143 and 144:
128• Charge-current ν τ interac
Page 145 and 146:
130• Tau likelihood selection eff
Page 147 and 148:
132Table 7.8: (For only SK-I) Summa
Page 149 and 150:
134Table 7.10: (Common to SK-I and
Page 151 and 152:
136because for non-zero θ 13 , Mul
Page 153 and 154:
138Bay [184] reactor experiments, a
Page 155 and 156:
140Table A.2: Summary of the damage
Page 157 and 158:
142Appendix BEnergy Flow AnalysisIn
Page 159 and 160:
Figure B.2: Example of subdivision
Page 161 and 162:
146be handled by setting any negati
Page 163 and 164:
148[16] K. Assamagan et al., Phys.
Page 165 and 166:
150[48] H. Seo, A Measurement of ν
Page 167 and 168:
152[84] T. H. Johnson et al., Phys.
Page 169 and 170:
154[125] G. Radecky et al., Phys. R
Page 171 and 172:
156[171] K. Hagiwara et al., Nucl.
show all

Tau Neutrino Appearance via Neutrino Oscillations in Atmospheric ...

Create successful ePaper yourself

Delete template?

Save as template?