Transcript Frontiers of Diffuse Analysis

Neutrino Oscillations Working Group
Parallel Session Summary
Kurt Woschnagg*
UC Berkeley
*WG co-lead with Ty DeYoung
IceCube collaboration meeting, Madison, May 11, 2013
Atmospheric Neutrino Oscillations
Search for muon neutrino disappearance in DeepCore data
Atmospheric Neutrino Oscillations
Theoretical oscillogram
Observables
Likelihood scan in
parameter space
Search for muon neutrino disappearance in DeepCore data
DeepCore is to IceCube as…
DeepCore is to IceCube as…
Oscillations WG Face Time in Madison 2013
Low-E/Oscillation Parallel on Thursday
IC79 νμ disappearance: results
(Christopher W)
IC79 νμ disappearance: details
(Laura Gladstone)
Oscillation Parallel on Friday
IC59 sterile neutrino search
(Marius Wallraff)
IC86 νμ disappearance: lessons
(Juan Pablo Yanez)
The next IC79 analysis
(Markus Vehring)
Sensitivity studies
(Julia Leute)
What are we doing next?
(Elisa Resconi)
IC79 “unblinding” result
best-fit values:
Sebastian Euler
Δm2 = 2 ∙ 10-3 eV2
sin2(2θ) = 1.0
rejection of no-osc.
hypothesis: ~9σ
using Wilks‘ theorem
systematics
included:
• normalizations
• spectral index
• optical efficiency
• p/K ratio
• ice model (partly)
• hole ice (partly)
Shown in Tuesday plenary, but…
IC79 “unblinding” “result”
best-fit values:
Sebastian Euler
Δm2 = 2 ∙ 10-3 eV2
sin2(2θ) = 1.0
rejection of no-osc.
hypothesis: ~9σ
using Wilks‘ theorem
systematics
included:
• normalizations
• spectral index
• optical efficiency
• p/K ratio
• ice model (partly)
• hole ice (partly)
Shown in Tuesday plenary, but…
Fit Projection: Length (Energy)
with
Oscillation
fit goes up
Unexpected
excess
Sebastian Euler | Analysis Call | 2013-05-02 | 9
Fit Projection: Zenith
But nuisance strongly
change
No strong effect by oscillations
Both cannot describe the data
No->Oscill
=2.71->2.59
normalisations change
Sebastian Euler | Analysis Call | 2013-05-02 | 10
IC79 νμ disappearance analyses
• Results not ready to be shown:
– Problems with full-year result (could be technical, bug,
problem with processing) ongoing investigation
• Laura Gladstone:
– Investigation of systematics sets (for Sebastian’s analysis)
– Optimization of likelihood scans
• Next generation analyses:
– Markus Vehring (IC79)
– Matt Dunkman (IC86)
IC59 sterile neutrinos: 3+1 flavor oscillations
Marius Wallraff
Use IC59 diffuse event sample (Anne Schukraft)
• High purity (>99.8%) and high statistics (>22,000 events)
• Good data/MC agreement
Under unblinding review in the Oscillation Group
IC59 sterile neutrino search
IC59 sterile neutrino search
Lessons learned from IC86 oscillation analysis
Juan Pablo Yanez
• We will never have enough CORSIKA livetime
• More is not always better
Lessons learned from IC86 oscillation analysis
• Parameterize systematics (if possible)
• Use Feldman-Cousins for final confidence regions
Sensitivity studies
Julia Leute
Sensitivity for 60 times higher statistics
(compared to IC79 analysis by Andreas Gross):
10 times higher efficiency × 6 years of data
Time to reflect…
• From SAC report:
musings by Elisa Resconi
“expected reach in the standard parameters,
Δm2 and sin2(2θ23), is really impressive”
“large amount of competition worldwide”
• Now that we are up and running:
– Are we organizing the work efficiently?
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Can we unify systematics treatment?
Can we unify event selection further?
Redundancies? Repetitions?
Don’t divide analyses according to year.
– Can we find complementary measurements?
• A discussion ensued…
Summary
• First generation analysis:
about to be published
• Second generation analyses:
unblinded (IC79 & IC86)
• Third generation analyses:
– Better tools, higher statistics,
multiyear data sets
– Will soon be limited by systematics
– Can make significant contribution to
oscillations sector (global fit)
• All this has developed quite rapidly
And now the results from Juan Pablo’s unblinding of IC86…
IC86 νμ disappearance
Results for the first year
• All nuisance parameters included, ice model coming (small change)
Value
Best fit
68% C.L.
1.0
> 0.944
2.40
+0.40 / -0.35
Parameter
Atm. μ
Spectral index
Value
7.6 %
2.65+0.012
νe deviation
-0.5 %
DOM eff.
+2.7%
Relative QE
Hole ice
135 + 0.13 %
54 cm
IC86 νμ disappearance
Results for the first year
Agreement of data and MC in 1D
projections
• 6σ rejection of no osc.
• χ2 = 48.8 / 54 dof
(5 bins with < 10 counts)
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PRELIMINARY
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*the distribution fitted is a 8x8 histogram
Plans
Result will be shown at ICRC
Work on simulation to
increase the E range
Better estimation of atm.
muon contamination
Add more data