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

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

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

DeepCore is to IceCube as…

DeepCore is to IceCube as… Seeing mostly downgoing stuff…

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 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…

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…

Fit Projection: Length (Energy) with Oscillation fit goes up Unexpected excess Sebastian Euler | Analysis Call | 2013-05-02 |

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 | 2013-05-02 |

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 MINOS, MiniBoone, CCFR, CDHS

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

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…

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 Value Atm. μ 7.6 % Spectral index 2.65+0.012 νe deviation -0.5 % DOM eff. +2.7% Relative QE 135 + 0.13 % Hole ice 54 cm PRELIMINARY

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