101 102 Eν [GeV] 0.0 0.2 0.4 0.6 0.8 1.0 P (νµ →νµ) cos(θ) = −1.00 (L = 12737 km) No sterile ∆m2 41 = 10 eV2 ∆m2 41 = 0.1 eV2 ∆m2 41 = 10−2 eV2 ∆m2 41 = 10−3 eV2 ∆m2 41 = 10−4 eV2 SK (2015): Phys. Rev. D 91, 052019 IC (2017): Phys. Rev. D 95, 112002 IC (2020): Phys. Rev. D 102, 052009 ANTARES (2019): J. HEP 2019, 113 MINOS+(2020): PRL 125, 071801 ORCA115: J. HEP 2021, 180 (2021) Sensitivity of KM3NeT/ORCA6 to light sterile neutrino mixing parameters Louis Bailly-Salinsa on behalf of the KM3NeT collaboration aUniversité de Caen Normandie, ENSICAEN, CNRS/IN2P3, LPC Caen UMR 6534, F-14000 Caen, France KM3NeT/ORCA Cherenkov neutrino telescope under construction in the Mediterranean sea. Atmospheric ν 1 - 100 GeV. Light Sterile Neutrino Analysis workflow ORCA6 510 days, 433 kton-year Expected number of events: Loss of sensitivity <10-2 eV2 1) Short BaseLine (SBL) anomaly: Δm2 41~ 1 eV2 MSW resonance > 1 TeV: hard to see with ORCA ORCA main feature on P(νµ→ νµ) at 1st osc. maximum (E~25 GeV for vertical upgoing νµ) θ24 & θ34 change amplitude; when both ≠0, change position depending on δ24 value Sensitivity Results 2) Dependency on Δm2 41 Wide range of E & L: can scan wide Δm2 41 range including very-low sterile (Δm2 41 <10-2 eV2) mass, not yet constrained by cosmology. E~25 GeV feature disappears for very low-mass, instead effects at ≤ 10 GeV (L/E > 1000 km/GeV) 101 102 103 104 Eν [GeV] 0.0 0.2 0.4 0.6 0.8 1.0 P (νµ →νµ) cos(θ) = −1.00 (L = 12737 km) No sterile sin2 θ24 = 0.1 sin2 θ34 = 0.1 sin2 θ24 = sin2 θ34 = 0.1 sin2 θ24=0.1 Determine parameters of interest x through Maximum Likelihood Estimator: (Poisson + Gaussian for constrained nuisance parameters η’) Std osc. params: NuFit 5.0 w/o SK + Daya Bay for Δm2 31 HONDA 2014 @ Fréjus, solar minimum GENIE 3 classes: low VS high-purity (LP / HP) tracks VS showers (BDT) Pν y→ν x(Et ,θt) σν x(Et) ϕatm ν y (Et,θt) Ri(Et,θt,ν x, Er ,θr) ni( Er,θr) × × × ⇒ ϕatm ν y (Et,θt) M eff ν x (Et) × νhor/νver skew νe/νe skew νµ/νµ skew νµ/νe skew Spectral index Overall norm. ντ-CC norm. NC norm. Energy scale HE light sim. HP track norm. Shower norm. Muon norm. Δm2 31 θ23 Systematics 1 Detection Unit (DU) = 18 DOMs 115 DUs when complete ⇒ 7 Mton instrumented water 3-D array of photomultiplier tubes: 1 Digital Optical Module (DOM) = 31 PMTs Constrained No prior Compare measured ni,j VS predicted µi,j 2D (Er, cos θr) reconstructed event distributions for each class i l (x , η)=2 ∑ i=1 N classes ∑ j =1 N bins [μi , j (x , η)−ni , j +ni , j ln( ni, j μi , j(x , η))]+∑ k=1 N priors ( ηk' −⟨ηk' ⟩ σk ) 2 ● Asimov data set in null hypothesis, both true mass ordering tested ● Assume Wilk’s theorem: Δl ∼χ2 2 ● No sensitivity to θ14 ⇒ θ14 = δ14 = 0 δ24 free unless stated otherwise HP tracks LP tracks Showers Total 1870 2002 1959 5831 Δm2 41- dependent sensitivities to θ24 and θ34 Sensitivity to Uµ4 and Uτ4 with Δm2 41 = 1 eV2 ORCA6 ≠ ORCA115 (21 Mt-y) ⇒ mostly from statistics ORCA6 not competitive for θ24 Close to SK and IC for θ34 Competitive for Uτ4 δ24 is important Δm2 41=1 eV2 Main goal: Neutrino Mass Ordering Here ORCA6 (6 DUs), operated Jan. 2020- Nov. 2021 References 10−3 10−2 10−1 100 sin2 θ24 10−4 10−3 10−2 10−1 100 101 ∆m2 41 [eV2] KM3NeT/ORCA6 Preliminary, 433 kt-y 99% CL sensitivity ORCA6 NO ORCA6 IO ORCA115 NO ORCA115 IO 99% CL upper limit SK (2015) IC (2020) MINOS+ (2020) 0.0 0.2 0.4 0.6 0.8 1.0 sin2 θ34 10−4 10−3 10−2 10−1 100 101 ∆m2 41 [eV2] KM3NeT/ORCA6 Preliminary, 433 kt-y 99% CL sensitivity ORCA6 NO, θ24 free ORCA6 IO, θ24 free ORCA6 NO, θ24 = 0 ORCA115 NO ORCA115 IO 99% CL upper limit IC (2017) SK (2015) 0.00 0.05 0.10 0.15 0.20 0.25 0.30 |Uµ4|2 = sin2 θ24 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 |Uτ4|2 = cos2 θ24 sin2 θ34 KM3NeT/ORCA6 Preliminary, 433 kt-y 99% CL sensitivity ORCA6 NO, δ24 free ORCA6 IO, δ24 free ORCA6 NO, δ24 = 0 ORCA115 NO ORCA115 IO 99% CL upper limit ANTARES (2019) IC (2017) SK (2015)