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Measuring Atmospheric Parameters with SuperBeams Enrique Fernández Martínez Departamento de Física Teórica and IFT Universidad Autónoma de Madrid
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Outline Introduction Oscillation parameters Experiments description Subleading effects in disappearance m 2 atm and the sign degeneracy 23 and the octant degeneracy The effects of 13 and T2K-1 bounds revised Conclusions
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The oscillation parameters What we already know Solar sector Atm sector What we still dont know sin2 13 < 0.40 cp Mass hierarchy Octant of 23 M. C. González García hep-ph/0410030 23 = 35º–55º 12 = 28º–38º
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Fluxes T2K-1SPL flux from decay at flux from decay L=130Km Old SPL fluxes courtesy of Gilardoni New fluxes Campagne et al. hep-ex/0411062 L=295Km T2K fluxes courtesy of J.J. Gómez Cadenas OA2º
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Event Rates T2K-1 B1B2B3B4 No osc. N 75322282273757 Signal N 46101381239 SPL - + No osc. N 2424525467 Signal N 17461614 L=130Km 5yr exposure with a 22.5Kt water cerenkov detector for T2K-1 2yr + 8yr exposure with a 440Kt water cerenkov detector for the SPL L=295Km Statistics dominatedSystematics dominated 4 energy bins of 200MeV Between 0.4 – 1.2GeV
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The importance of energy resolution 13 = 0º = 0º T2K-1SPL 90% CL contours 5% systematic error and backgrounds taken into account
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The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE27.0
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The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV
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The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV E2 = 0.6 - 0.8GeV
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The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV E2 = 0.6 - 0.8GeV E3 = 0.8 - 1.0GeV
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The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV E2 = 0.6 - 0.8GeV E3 = 0.8 - 1.0GeV E4 = 1.0 - 1.2GeV
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The importance of energy resolution T2K-1SPL 13 = 0º = 0º GeVE25.0 GeVE27.0 E1 = 0.4 - 0.6GeV E2 = 0.6 - 0.8GeV E3 = 0.8 - 1.0GeV E4 = 1.0 - 1.2GeV
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The disappearance channel Where 231213 2sin2 2 cos ~ J sin 2 13 < 0.4 05.0 2 L sol E m 2 2 12 E. K. Akhmedov et al. hep-ph/0402175 A. Donini et al. hep-ph/0411402 E m atm 2 2 23
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The sign degeneracy Input: 13 = 0º = 0º L L sol atm + O 2 2 sin 2 2sin1 2 23 2 L sol + O 2
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The sign degeneracy L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 Input: 13 = 0º = 0º
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The sign degeneracy Fit assuming inverted hierarchy Input: 13 = 0º = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2
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The octant degeneracy Input: 13 = 0º = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2
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The octant degeneracy Input: 13 = 0º = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2
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The effect of 13 Input: 13 = 0º = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2
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The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23
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The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23
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The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º, 4º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23
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The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º, 4º, 6º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23
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The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º, 4º, 6º, 8º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23
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The effect of 13 Input: 13 = 0º = 0º Assuming 13 = 0º, 2º, 4º, 6º, 8º, 10º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23
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The effect of Input: 13 = 8º = 0º Assuming = 0º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23
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The effect of Input: 13 = 8º = 0º Assuming = 0º, 90º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23
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The effect of Input: 13 = 8º = 0º Assuming = 0º, 90º, 180º L Ls L L sol atm sol atm + O 2 sin2 2 2 sin 2 2sin1 2 23 22 12 23 2 s 2cos2sin 23 2 13 22 23 sJ cos ~ 2 23
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T2K-1 errors revised m 2 = (2.43 – 2.60)·10 -3 eV 2 sin 2 2 > 0.97 tan 2 = 0.73 – 1.39 m 2 = (2.50 ± 0.06)·10 -3 eV 2 sin 2 2 > 0.98 Y. Itow et al. hep-ex/0106019 m 2 = (2.45 – 2.56)·10 -3 eV 2 sin 2 2 > 0.98 tan 2 = 0.76 – 1.31 Present: m 2 = (1.7 – 3.5)·10 -3 eV 2 sin 2 2 > 0.9 tan 2 = 0.53 – 2.04 m 2 = (-2.63 – -2.49)·10 -3 eV 2 Input: 13 = 0º 23 = 45º = 0º 90% CL
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T2K-1 errors revised m 2 = (2.42 – 2.61)·10 -3 eV 2 sin 2 2 = 0.94 – 0.99 tan 2 = 0.62 – 0.85, 1.21 – 1.66 m 2 = (2.44 – 2.58)·10 -3 eV 2 sin 2 2 = 0.95 – 0.99 tan 2 = 0.63 – 0.81, 1.24 – 1.58 Present: m 2 = (1.7 – 3.5)·10 -3 eV 2 sin 2 2 > 0.9 tan 2 = 0.53 – 2.04 m 2 = (-2.64 – -2.47)·10 -3 eV 2 90% CL Input: 13 = 0º 23 = 40º = 0º
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Conclusions The measurement of 13 and will rely heavily on an improvement of the measure of 23 and m 2 23 Precision measurements of 23 and m 2 23 need energy resolution and events above and below the oscillation peak The errors on the 23 and m 2 23 are somewhat larger due to the dependence of the disappearance signal on 13, and the mass hierarchy This dependence can be exploited combined with the appearance channel to solve degeneracies
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T2K-2 T2K-1 5% systematic error
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T2K-2 T2K-1 2% systematic error
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No background and no systematic Systematic 0% No Background Systematic 5% With Background Errors dominated by statistics
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10% systematic Systematic 10%Systematic 5% Errors dominated by statistics
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Energy Resolution Red histogram for true QE events Figure taken from Y. Itow et al. hep-ex/0106019
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Double energy resolution 4 bins of 200MeV 8 bins of 100MeV
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Double energy resolution 4 bins of 200MeV 8 bins of 100MeV
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