Status and results of KM3NeT/ORCA

Status and results of KM3NeT/ORCA Alfonso Lazo Pedrajas on behalf of the KM3NeT Collaboration Physics motivation 2 Supernovae Dark Matter & exotic searches High-energy neutrino astronomy ~ MeV ~ GeV ~ GeV - TeV ~ TeV - PeV Cosmic Rays & Neutrino properties Physics motivation 3 Supernovae Cosmic Rays & Neutrino properties Dark Matter & exotic searches High-energy neutrino astronomy ~ MeV ~ GeV ~ GeV - TeV ~ TeV - PeV This talk See ARCA talk ORCA +ARCA ARCA KM3NeT Infrastructure 4 Two sites, one technology Credit: P. De Jong ๏Water-Cherenkov neutrino telescope under construction in the Mediterranean Sea, 40 km offshore Toulon (Fr) ๏18 Multi-PMT Digital Optical Modules (DOMs) along vertical Detection Units (DUs) ๏115 DUs foreseen ๏~20m horizontal DU spacing, ~9m vertical DOM spacing ๏Detection of Cherenkov light induced by secondary charged particles from neutrino interactions ๏Main goal: Measurement of the Neutrino Mass Ordering (NMO) and neutrino oscillation parameters KM3NeT/ORCA 5 Cosmic-Ray Physics ๏Underwater detection of TeV-muon flux produced in air showers ๏Deficit w.r.t. state-of-the-art simulation consistent with measurements at sea level ๏Atmospheric muons used for time calibration between DOMs and DUs Cosmic Rays in ORCA 7 Eur. Phys. J. C 84 (2024) no.7, 696 Eur. Phys. J. C 83, 344 (2023) ๏Moon and Sun shadowing effect on CR flux observed at and ๏Demonstration of good understanding on detector positioning, orientation and time calibration 4.2σ 6.2σ ORCA6 σres = (0.53 ±0.04)∘ ๏Empirical light detection PDFs built from num. hits detected over total number of PMTs that could have detected hits given a muon track ๏Data PDFs are compared to the MC prediction under different assumptions of absorption length and light yield normalisation Cosmic Rays in ORCA 8 ๏New approach uses stopping muons (mostly MIPs < 100 GeV) to measure the water absorption length with ORCA6 data ๏Dominant systematic in most ORCA analyses PoS(ICRC2025)1158 Neutrino oscillations PID classes 16 ๏~95% purity, negligible bkg. ๏Most sensitive to disappearance νμ+ ¯νμ νμ, ¯νμ ๏~17% atm. muon bkg. ๏Sensitive to oscillations and constrains systematics ๏91% accuracy in classifying as showers ๏Sensitive to appearance νe+ ¯νe νe 400 450 500 550 600 650 700 °2 log L 0 2 4 6 8 10 12 Percentage of PEs [%] p-value: NO = 0.41 IO = 0.41 KM3NeT/ORCA6-10-11 Preliminary, 715 kt-y True NO True IO Data 10 20 30 Reconstructed Energy [GeV] 10 20 30 Reconstructed Energy [GeV] 10 20 30 Reconstructed Energy [GeV] 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Data HP Tracks 10 20 30 40 50 60 Events 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Data LP Tracks 10 20 30 40 50 60 Events 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Data Showers 10 20 30 40 50 60 Events 10 20 30 Reconstructed Energy [GeV] 10 20 30 Reconstructed Energy [GeV] 10 20 30 Reconstructed Energy [GeV] 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Simulations HP Tracks 10 20 30 40 50 60 Events 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Simulations LP Tracks 10 20 30 40 50 60 Events 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Simulations Showers 10 20 30 40 50 60 Events ๏Compare data and MC template in 2D space of reconstructed track or shower energy and direction ๏Excellent data/MC agreement with goodness-of-fit p-value of 41% Improved measurement 17 400 450 500 550 600 650 700 °2 log L 0 2 4 6 8 10 12 Percentage of PEs [%] p-value: NO = 0.41 IO = 0.41 KM3NeT/ORCA6-10-11 Preliminary, 715 kt-y True NO True IO Data 10 20 30 Reconstructed Energy [GeV] 10 20 30 Reconstructed Energy [GeV] 10 20 30 Reconstructed Energy [GeV] 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Data HP Tracks 10 20 30 40 50 60 Events 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Data LP Tracks 10 20 30 40 50 60 Events 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Data Showers 10 20 30 40 50 60 Events 10 20 30 Reconstructed Energy [GeV] 10 20 30 Reconstructed Energy [GeV] 10 20 30 Reconstructed Energy [GeV] 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Simulations HP Tracks 10 20 30 40 50 60 Events 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Simulations LP Tracks 10 20 30 40 50 60 Events 2 4 -1.0 -0.8 -0.6 -0.4 -0.2 0 Reconstructed cos µz 50 102103 KM3NeT/ORCA Preliminary, 715 kt-y Simulations Showers 10 20 30 40 50 60 Events ๏Compare data and MC template in 2D space of reconstructed track or shower energy and direction ๏Excellent data/MC agreement with goodness-of-fit p-value of 41% Improved measurement 18 °4°2 0 2 4 2(ln LIO °ln LNO) 0 2 4 6 8 10 Percentage of PEs [%] True µ23 NuFIT v5.0 Upper Octant p-value: NO = 0.08 IO = 0.82 KM3NeT/ORCA6-10-11 Preliminary, 715 kt-y True NO True IO Data Improved measurement 19 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 NO KM3NeT/ORCA Preliminary, 715 kt-y 90% C.L. NOvA 2022 T2K 2023 SK 2023 MINOS+ 2018 IceCube 2024 (NO) KM3NeT 715 kt-y 0.3 0.4 0.5 0.6 0.7 sin2µ23 °3.00 °2.75 °2.50 °2.25 °2.00 °1.75 °1.50 IO ¢m2 31[10°3eV2] Δm2 31 ={−2.09+0.17 −0.21 ×10−3eV2, IO [2.10,2.37] ×10−3eV2,NO sin2θ23 = 0.50 ±0.07 2 log(ℒIO /ℒNO) = 0.61 S. Peña-Martínez @Neutrino2024 Bayesian measurement 20 Posterior predictive p-value PoS(ICRC2025)1092 ๏Uses Markov Chain Monte Carlo to sample the posterior PDF ๏Comprehensive probabilistic description of oscillation parameters ๏Offers scalable inference in extended parameter spaces ๏Facilitates methodological consistency with Long-baseline experiments ๏ candidates measured in 433 kton-yr of ORCA6, tau neutrino normalisation best fit at . ๏Results recasted into averaged CC cross-section measurement as at mean tau neutrino energy of 20 GeV ๏Measurement competitive with other experiments 92+90 −63 ντ+ ¯ντ Sτ= 0.48+0.5 −0.33 ντ& ¯ντ στ= (2.5+2.6 −1.8)×10−38 cm2 Tau neutrino appearance 21 J. High Energ. Phys. 2025, 213 (2025) ๏What if … neutrinos experienced Non-Standard Interactions (NSI) in their forward scattering through the Earth? ๏Neutrino flavours couple to non-universal and flavour-changing NC interactions beyond the SM Oscillations and beyond 22 ๏What if … neutrino mass eigenstates interacted with their environment and lost their coherent superposition? (Quantum Decoherence) ๏Atm. oscillations observed consistently with SM predictions, but strong bounds were placed on BSM models using 433 kton-yr of ORCA6 ν JCAP 02 (2025) 073 JCAP 03 (2025) 039 ๏Two independent probes for signatures of sterile neutrinos have been employed based on 433 kton-yr of exposure Search for sterile neutrinos 23 J. High Energ. Phys. 2025, 213 (2025) PoS(ICHEP2024)155 ๏Non-unitarity model explores the modification of the left-handed neutrino mixing due to the presence of heavy sterile states ๏Active-sterile mixing constrained based on the effect of an eV-scale sterile neutrino on the first oscillation maximum νμ→ντ α11 0 0 α21 α22 0 α31 α32 α33 ×UPMNS Full-detector projections 24 ๏ORCA115 alone can reach NMO significance in case of true NO in 3 years of data taking ( in 5 years for true IO) assuming current oscillation global fits ๏Combination with JUNO significantly reduces the time needed in any scenario and improves over the simple sum of likelihoods 5σ 3σ Eur. Phys. J. C 82, 26 (2022) JHEP 03 (2022) 055 Data already recorded should further improve upon these scenarios! Dark matter ๏The reception of acoustic signals from a network of emitters on the seafloor is used to fit a mechanical model of the DU motion Position calibration 32 See talk by R. Clark (1/10/25) Buoy Anchor Emitter DOM 18 DOM 1 Tilt Twist Orientation Amplitude Credit: N. Lessing °1.00 °0.75 °0.50 °0.25 0.00 0.25 0.50 0.75 1.00 (|¢m2,shift 31 |°|¢m2,bf 31 |)/æ|¢m2 31| HP Track Norm NC Norm sin2µ23 Energy Scale Shower Norm Muon Norm ∫ø-CC Norm ∫µ/¯∫µ HE Light Sim Overall Norm ∫hor/∫ver ∫e/¯∫e Spectral Index ∫µ/∫e KM3NeT/ORCA Preliminary, 715 kt-y Plus shift Minus shift Syst. pulls °4°3°2°1 0 1 2 3 4 (≤bf °≤cv)/æ≤ °1.00 °0.75 °0.50 °0.25 0.00 0.25 0.50 0.75 1.00 (sin2µshift 23 °sin2µbf 23)/æsin2µ23 ∫ø-CC Norm Spectral Index HE Light Sim ∫µ/¯∫µ ∫e/¯∫e ∫µ/∫e ∫hor/∫ver Overall Norm HP Track Norm Shower Norm Energy Scale Muon Norm NC Norm |¢m2 31| KM3NeT/ORCA Preliminary, 715 kt-y Plus shift Minus shift Syst. pulls °4°3°2°1 0 1 2 3 4 (≤bf °≤cv)/æ≤ Nuisance parameters 33 ๏Systematics implemented to model uncertainties on event type normalisations, cross sections, detector response, water properties and atmospheric flux Full-detector performance 34 Full-detector performance 35 Δχ2 NO-IO ๏50k, 60k and 65k events expected in three years for track, intermediate and shower classes ๏Most NMO-sensitive region is in the shower class around the MSW resonance. ๏Abundant sample of atmospheric will enable unprecedented precision ντ ๏Frequentist: Maximum Likelihood estimation of parameters & profiled likelihood ratio. Statistical method 36 −2 log ℒ= nrec ∑ i min {βi}2βiMi−Di+Dilog (Di βiMi)+(βi−1)2 σ2 β,i +∑ k(ηk−⟨ηk⟩ σk)2 −2Δlog ℒ(α) = −2 log (ℒ(α) ℒBF ) ๏Bayesian: inference on the credible region of model parameters by integrating the posterior PDF, sampled from an MCMC. Ω P( ω∈ Ωα|D) = ∫ ω′ ∈Ωα∫∞ −∞ P( ω′ ,η|D) d ηd ω′ =α ๏Search for isotropic Lorentz invariance violation (LIV) in atmospheric neutrinos ๏Constrained all mass dimension 3 coefficients and and diagonal up to dimension 8 ๏Competitive constraints on the dimension 3 compared to SK and IC ๏Combined search planned with IC and ANTARES μμ −ττ LIV in ORCA6 37 ๏Used 433 kton-yr dataset ๏Compatible with existing measurements and studies Neutrino decay 38 αBF 3= 0.92+1.08 −0.57 ×10−4eV2