Etude et impact du bruit de fond corrÃ©lÃ© pour la mesure de l'angle ...

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100 4. Measurement of ✓ 13 with the Double Chooz far detector Source 1st result 2nd result Numbers Unc. [%] Numbers Unc. [%] Statistics 4121 1.6 8249 1.1 tel-00821629, version 1 - 11 May 2013 Live time [d] 99 -- 228 -- Reactor prediction -- 1.7 -- 1.7 Energy scale -- 1.7 -- 0.3 Trigger Efficiency [%] 100 < 0.1 100 < 0.1 Gd fraction [%] 85.7±0.3 0.6 86.5±0.5 0.3 Detection !E cut [%] 94.5±0.6 0.6 94.1±0.2 0.7 efficiencies !t cut [%] 96.5±0.5 0.5 96.2±0.2 0.5 Spill-in/out [%] 1.4 0.4 1.35 0.3 Target H 6.747"10 29 0.3 6.747"10 29 0.3 Accidental [cpd] 0.33±0.03 < 0.1 0.261±0.002 < 0.1 Background Cosmogenic [cpd] 2.3±1.2 2.8 1.25±0.54 1.4 Correlated [cpd] 0.83±0.38 0.9 0.67±0.20 0.5 Table 4.2: Summary table of the parameters for the measurement of ✓ 13 . The parameters obtained for the first DC publication [19] are also reported for comparison.
4.6 Final fit and measurement of ✓ 13 101 energy bin as: N exp. i = rxt. X R N ⌫,R i + bkg. X b N b i (4.3) where the i runs over the 18 bins, b represents the three background contributions and R the two reactors. The oscillation hypothesis is taken into account on the expected number of ¯⌫ e events N ⌫,R i , by the survival probability, as a function of ✓ 13 : P (E,✓ 13 ) = P¯⌫e!¯⌫ e (✓ 13 ,E) ( = 1 sin 2 (2✓ 13 )sin 2 ✓ 1.27 ⇥ m 2 31 ⇥ L[m] E[MeV] ◆ ) tel-00821629, version 1 - 11 May 2013 Due to reactor thermal power fluctuations, the ¯⌫ e rate changes as function of the time as show in Fig. 4.9. While the ¯⌫ e signal changes, the background rate remains constant over the time, so the background to signal ratio (B/S) changes. The data are divided in two integration periods based on thermal power of the two reactors [59]. During the first period both reactors were above 20 % of thermal power, while during the second period the thermal power of one of the two reactors was below 20 %. The background populations are obtained in agreement with measured rates and live time of the detector during each integration period. The B/S ratio change from ⇠ 4.99 % of the first period to ⇠ 8.95 % of the second period. The fit is performed simultaneously over the combined 36 bins of both integration period. Such technique take advantage of the di↵erent B/S ratios in each period and add information about background behaviour to the fit. Tab. 4.3 summarise observed signal, expected signal and background expectation for the two integration periods. The statistical uncertainty and systematic e↵ects inducing uncertainties on the expected energy spectrum are taken into account in a mixed approach. Statistical fluctuation and systematic uncertainties on the reactor simulations, the detector response and background spectral shape are directly taken into account in the 2 function through a covariance matrix: M i,j = M stat. i,j + M rxt. i,j + M det. i,j + bkg. X b M bkg. i,j (4.4) Each term represents the covariance between i-bin and j-bin due to a given uncertainty source. The normalisation uncertainty associated with each matrix is summarised in Tab. 4.2. The reactor covariance matrix account the knowledge about the predicted neutrino spectra. The cosmogenic background matrix contains contribution due to the spectral shape uncertainty, estimated with di↵erent MC event generation parameters. The correlated background matrix account for the spectral shape slope, which is allowed
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UNIVERSITÉ DENANTES FACULTÉ DES S
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tel-00821629, version 1 - 11 May 20
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Abstract tel-00821629, version 1 -
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Acknowledgments Since so many peopl
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Contents 1 Introduction 13 tel-0082
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CONTENTS 11 tel-00821629, version 1
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Chapter 1 Introduction tel-00821629
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15 tel-00821629, version 1 - 11 May
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Chapter 2 Neutrino physics tel-0082
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2.2 Neutrino history in brief 19 ma
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2.3 Neutrino oscillation, the theor
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2.4 Measuring neutrino oscillation
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3-flavour oscillations The dominant
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After the Sun, the other main natur
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2.5 The problem with the neutrino m
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2.6 Summary and open questions 37 s
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In the next future, reactor experim
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Chapter 3 The Double Chooz experime
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3.1 The Double Chooz detector 43 to
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3.1 The Double Chooz detector 45 te
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3.1 The Double Chooz detector 47 it
Page 49 and 50: 3.1 The Double Chooz detector 49 te
Page 51 and 52: 3.2 The detector read-out 51 40 m o
Page 53 and 54: 3.3 The online system 53 IV trigger
Page 55 and 56: 3.3 The online system 55 tions as s
Page 57 and 58: 3.3 The online system 57 tel-008216
Page 59 and 60: 3.4 The calibration system 59 tel-0
Page 61 and 62: loosing their kinetic energy 3 and
Page 63 and 64: 3.5 Reactor neutrino flux simulatio
Page 69 and 70: 3.8 Data reconstruction 69 A dedica
Page 71 and 72: Regarding the pulse information, th
Page 73 and 74: 3.8 Data reconstruction 73 tel-0082
Page 75 and 76: 3.8 Data reconstruction 75 Gain (ch
Page 77 and 78: 3.9 Conclusions 77 tel-00821629, ve
Page 79 and 80: Chapter 4 Measurement of ✓ 13 wit
Page 81 and 82: 4.1 Data sample 81 create a signal
Page 83 and 84: 4.2 ¯⌫ e signal selection 83 Liv
Page 85 and 86: 4.2 ¯⌫ e signal selection 85 Pro
Page 87 and 88: 4.2 ¯⌫ e signal selection 87 Neu
Page 89 and 90: 4.3 Backgrounds 89 energy spectrum
Page 91 and 92: 4.3 Backgrounds 91 tel-00821629, ve
Page 93 and 94: 4.4 Selection e ciencies and system
Page 95 and 96: 4$&14+#':"'$"$468'#21%$;' ! $"$468'
Page 97 and 98: 4.4 Selection ! e ciencies and syst
Page 99: 4.5 Data analysis summary 99 4.4.3
Page 103 and 104: 4.6 Final fit and measurement of
Page 105 and 106: 4.7 Summary and Conclusions 105 tel
Page 107 and 108: Chapter 5 Correlated background tel
Page 109 and 110: 5.1 Measuring correlated background
Page 111 and 112: 5.2 High energy analysis 111 in a l
Page 113 and 114: 5.2 High energy analysis 113 tel-00
Page 115 and 116: 5.3 OV Tag analysis 115 The t cut v
Page 117 and 118: 5.4 Fast Neutrons analysis 117 bigg
Page 119 and 120: 5.4 Fast Neutrons analysis 119 5.4.
Page 121 and 122: 5.4 Fast Neutrons analysis 121 tel-
Page 123 and 124: 5.4 Fast Neutrons analysis 123 esti
Page 125 and 126: 5.4 Fast Neutrons analysis 125 Corr
Page 129 and 130: 5.4 Fast Neutrons analysis 129 Prom
Page 131 and 132: 5.4 Fast Neutrons analysis 131 lect
Page 133 and 134: 5.4 Fast Neutrons analysis 133 mari
Page 139 and 140: 5.5 Stopping Muon analysis 139 5.5.
Page 141 and 142: 5.5 Stopping Muon analysis 141 tel-
Page 143 and 144: 5.5 Stopping Muon analysis 143 tel-
Page 145 and 146: 5.5 Stopping Muon analysis 145 Sour
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5.6 Estimation of correlated backgr
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5.7 Conclusion 157 5.7 Conclusion t
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Chapter 6 Conclusions tel-00821629,
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161 • The SM analysis could be im
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Chapter 7 Contributions to Double C
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165 from this study and from [64] f
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List of Figures tel-00821629, versi
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LIST OF FIGURES 169 tel-00821629, v
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List of Tables 3.1 Mean energy rele
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Bibliography [1] [2] tel-00821629,
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BIBLIOGRAPHY 183 [31] J.K. Ahn et a
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BIBLIOGRAPHY 185 [61] W. Hampel et
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BIBLIOGRAPHY 187 [92] A. Stueken et
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