measuring atmospheric parameters with superbeams enrique fernández martínez departamento de...
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Measuring Atmospheric Parameters with SuperBeams
Enrique Fernández MartínezDepartamento de Física Teórica and IFT
Universidad Autónoma de Madrid
Outline
Introduction Oscillation parameters Experiments description
Subleading effects in disappearance m2
atm and the sign degeneracy 23 and the octant degeneracy The effects of 13 and
T2K-1 bounds revised Conclusions
The oscillation parameters
What we already know
Solar sector
Atm sector
What we still don’t know sin213 < 0.40
cp
Mass hierarchy
Octant of 23
21.011.012
2
251.19.0
212
39.0tan
eV102.8
m
1.15.023
2
234.16.0
223
1tan
eV102.2
m
223msignsatm
232tan signsoct
M. C. González García hep-ph/0410030
23 = 35º–55º
12 = 28º–38º
Fluxes
T2K-1 SPL
flux from decay at GeVE 75.0
flux from decay flux from decay
GeVE 27.0
GeVE 25.0
L=130Km
Old SPL fluxes courtesy of GilardoniNew fluxes Campagne et al. hep-ex/0411062
L=295Km
T2K fluxes courtesy of J.J. Gómez Cadenas
OA2º
Event Rates
T2K-1 B1 B2 B3 B4 No osc.
N
753 2228
2273
757
Signal N
46 101 381 239
SPL -
+
No osc. N
24245 25467
Signal N1746 1614
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 dominated Systematics dominated
4 energy bins of 200MeV Between 0.4 – 1.2GeV
The importance of energy resolution
13 = 0º = 0º
T2K-1 SPL
90% CL contours 5% systematic error and backgrounds taken into account
The importance of energy resolution
T2K-1 SPL
13 = 0º = 0º GeVE 27.0
The importance of energy resolution
T2K-1 SPL
13 = 0º = 0º
GeVE 25.0
GeVE 27.0E1 = 0.4 - 0.6GeV
The importance of energy resolution
T2K-1 SPL
13 = 0º = 0º
GeVE 25.0
GeVE 27.0E1 = 0.4 - 0.6GeVE2 = 0.6 - 0.8GeV
The importance of energy resolution
T2K-1 SPL
13 = 0º = 0º
GeVE 25.0
GeVE 27.0E1 = 0.4 - 0.6GeVE2 = 0.6 - 0.8GeVE3 = 0.8 - 1.0GeV
The importance of energy resolution
T2K-1 SPL
13 = 0º = 0º
GeVE 25 .0
GeVE 27 .0E1 = 0.4 - 0.6GeVE2 = 0.6 - 0.8GeVE3 = 0.8 - 1.0GeVE4 = 1.0 - 1.2GeV
The importance of energy resolution
T2K-1 SPL
13 = 0º = 0º
GeVE 25 .0
GeVE 27 .0E1 = 0.4 - 0.6GeVE2 = 0.6 - 0.8GeVE3 = 0.8 - 1.0GeVE4 = 1.0 - 1.2GeV
The disappearance channel
LscL
LsJsL
Ls
atmsol
atmsol
atm
cos2sin2sin2
sincos~
2sin2
2sin22cos2sin2sin1
2322
121224
23
2
22323
2212
232
1322
23232
P
Where
23121313 2sin2sin2sincos~ J
sin 213 < 0.4 05.02
Lsol
E
msol
2
212
E. K. Akhmedov et al. hep-ph/0402175A. Donini et al. hep-ph/0411402
E
matm
2
223
The sign degeneracy
Input:13 = 0º = 0º
L
L
sol
atm
+ O
2
2sin22sin1
2
232 P
Lsol
+ O2
The sign degeneracy
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P
Input:13 = 0º = 0º
The sign degeneracy
Fit assuming inverted hierarchy
Input:13 = 0º = 0º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P
The octant degeneracy
Input:13 = 0º = 0º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P
The octant degeneracy
Input:13 = 0º = 0º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P
The effect of 13
Input:13 = 0º = 0º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P
The effect of 13
Input:13 = 0º = 0º
Assuming 13 = 0º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P s 2cos2sin 232
1322
23
sJ cos~ 223
The effect of 13
Input:13 = 0º = 0º
Assuming 13 = 0º, 2º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P s 2cos2sin 232
1322
23
sJ cos~ 223
The effect of 13
Input:13 = 0º = 0º
Assuming 13 = 0º, 2º, 4º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P s 2cos2sin 232
1322
23
sJ cos~ 223
The effect of 13
Input:13 = 0º = 0º
Assuming 13 = 0º, 2º, 4º, 6º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P s 2cos2sin 232
1322
23
sJ cos~ 223
The effect of 13
Input:13 = 0º = 0º
Assuming 13 = 0º, 2º, 4º, 6º, 8º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P s 2cos2sin 232
1322
23
sJ cos~ 223
The effect of 13
Input:13 = 0º = 0º
Assuming 13 = 0º, 2º, 4º, 6º, 8º, 10º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P s 2cos2sin 232
1322
23
sJ cos~ 223
The effect of
Input:13 = 8º = 0º
Assuming = 0º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P s 2cos2sin 232
1322
23
sJ cos~ 223
The effect of
Input:13 = 8º = 0º
Assuming = 0º, 90º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P s 2cos2sin 232
1322
23
sJ cos~ 223
The effect of
Input:13 = 8º = 0º
Assuming = 0º, 90º, 180º
L
LsL
L
sol
atmsol
atm
+ O
2
sin2sin2
2sin22sin1
2
2322
12
232
P s 2cos2sin 232
1322
23
sJ cos~ 223
T2K-1 errors revised
m2 = (2.43 – 2.60)·10-3 eV2
sin22 > 0.97 tan2 = 0.73 – 1.39
m2 = (2.50 ± 0.06)·10-3 eV2
sin22 > 0.98 Y. Itow et al. hep-ex/0106019
m2 = (2.45 – 2.56)·10-3 eV2
sin22 > 0.98 tan2 = 0.76 – 1.31
Present:m2 = (1.7 – 3.5)·10-3 eV2
sin22 > 0.9 tan2 = 0.53 – 2.04
m2 = (-2.63 – -2.49)·10-3 eV2
Input:13 = 0º 23 = 45º = 0º
90% CL
T2K-1 errors revised
m2 = (2.42 – 2.61)·10-3 eV2
sin22 = 0.94 – 0.99 tan2 = 0.62 – 0.85, 1.21 – 1.66m2 = (2.44 – 2.58)·10-3 eV2
sin22 = 0.95 – 0.99tan2 = 0.63 – 0.81, 1.24 – 1.58
Present:m2 = (1.7 – 3.5)·10-3 eV2
sin22 > 0.9 tan2 = 0.53 – 2.04
m2 = (-2.64 – -2.47)·10-3 eV2
90% CL
Input:13 = 0º 23 = 40º = 0º
Conclusions
The measurement of 13 and will rely heavily on an improvement of the measure of 23 and m2
23 Precision measurements of 23 and m2
23 need energy resolution and events above and below the oscillation peak
The errors on the 23 and m223 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
T2K-2
T2K-2T2K-1
5% systematic error
T2K-2
T2K-2T2K-1
2% systematic error
No background and no systematic
Systematic 0%No Background
Systematic 5%With Background
Errors dominated by statistics
10% systematic
Systematic 10%Systematic 5%
Errors dominated by statistics
Energy Resolution
Red histogram for true QE eventsFigure taken fromY. Itow et al. hep-ex/0106019
Double energy resolution
4 bins of 200MeV 8 bins of 100MeV
Double energy resolution
4 bins of 200MeV 8 bins of 100MeV