1. Neutrino Oscillations Working Group Parallel Session Summary
Kurt Woschnagg*
UC Berkeley
*WG co-lead with Ty DeYoung
Working group formed after Aachen meeting – split off from Diffuse group
Biweekly phone calls (~20 participants)
IceCube collaboration meeting, Madison, May 11, 2013

2. Atmospheric Neutrino Oscillations
Our bread-and-butter analysis: standard oscillations of muon neutrinos into tau neutrinos
Search for muon neutrino disappearance in DeepCore data

3. Atmospheric Neutrino Oscillations
Theoretical oscillogram
Our bread-and-butter analysis: standard oscillations of muon neutrinos into tau neutrinos
Observables
Likelihood scan in
parameter space
Search for muon neutrino disappearance in DeepCore data

4. DeepCore is to IceCube as…

5. DeepCore is to IceCube as…
Seeing mostly downgoing stuff…

6. 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)

7. IC79 “unblinding” result
Sebastian Euler
best-fit values:
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…

8. IC79 “unblinding” “result”
Sebastian Euler
best-fit values:
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…

9. Fit Projection: Length (Energy)
with Oscillation
fit goes up
Unexpected excess
Sebastian Euler | Analysis Call | |

10. Fit Projection: Zenith
But nuisance strongly change
No->Oscill
=2.71->2.59
normalisations change
No strong effect by oscillations
Both cannot describe the data
Sebastian Euler | Analysis Call | |

11. 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)

12. 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

13. IC59 sterile neutrino search
MINOS, MiniBoone, CCFR, CDHS

14. IC59 sterile neutrino search

15. Lessons learned from IC86 oscillation analysis
Juan Pablo Yanez
We will never have enough CORSIKA livetime
More is not always better

16. Lessons learned from IC86 oscillation analysis
Parameterize systematics (if possible)
Use Feldman-Cousins for final confidence regions

17. 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
Six years of Sebastian’s data with the precision of Andreas’s data

18. Time to reflect… musings by Elisa Resconi From SAC report:
“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?
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…

19. 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…

20. 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
Value
Atm. μ
7.6 %
Spectral index
νe deviation
-0.5 %
DOM eff.
+2.7%
Relative QE %
Hole ice
54 cm
PRELIMINARY

21. IC86 νμ disappearance Results for the first year
6σ rejection of no osc.
χ2 = 48.8 / 54 dof
(5 bins with < 10 counts)
Plans
Result will be shown at ICRC
Work on simulation to increase the E range
Better estimation of atm. muon contamination
Add more data
Agreement of data and MC in 1D projections
PRELIMINARY
*the distribution fitted is a 8x8 histogram