Publications digest
Recent preprints & papers
A curated selection of recent papers in neutrino physics, with editorial digests and one-line takeaways. Inclusion is based on relevance to active open questions in the field, not on impact metrics.
April 2026
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NOvA full-exposure measurement of θ₂₃ and δ_CP with 4.4 × 10²¹ POT
A combined disappearance and appearance fit to NOvA's full beam exposure prefers normal ordering at 1.9σ, with sin²θ₂₃ = 0.59 (NO, upper octant) and δ_CP = -0.62π. The shift toward maximal CP-violating values is consistent with T2K but at modest significance.
Takeaway Octant tension with T2K narrows; full T2K + NOvA + JUNO joint fit expected late 2026.
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P-ONE Cluster 1 deployment and first photon-rate measurements in the deep Pacific
P-ONE Cluster 1 — seven 1-km-long strings with 70 optical modules each — was deployed at the Cascadia Basin site in November 2025. First-light photon-rate measurements confirm absorption length and scattering length within design specification; full-cluster operation begins May 2026.
Takeaway P-ONE moves from R&D to operational. First diffuse-astrophysical-flux paper expected within 18 months.
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Hyper-Kamiokande cavern excavation complete: status report and beam-physics readiness
The Hyper-K cavern excavation at Kamioka completed in March 2026. PMT mass-installation begins Q3 2026; first water fill scheduled Q4 2027. The 258 kt detector will commence data-taking in 2028 with a 2.5° off-axis J-PARC beam at 1.3 MW.
Takeaway On schedule. Combined Hyper-K + DUNE δ_CP discovery within the first three years of joint running becomes a reasonable expectation.
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Evidence for a galactic plane component in the tau-flavour neutrino flux at IceCube
A combined analysis of 12 years of starting-track and double-cascade events isolates a sub-population of astrophysical neutrinos consistent with originating along the galactic plane, including a measurable tau-flavour fraction. Significance for galactic ν_τ contribution: 3.4σ.
Takeaway First indication of galactic-plane tau emission. Below discovery threshold; IceCube-Gen2 expected to settle within five years.
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First measurement of inclusive electron-neutrino + electron-antineutrino cross sections on argon at GeV energies
MicroBooNE reports the first inclusive ν_e + ν̄_e cross-section measurement on argon, a critical input for DUNE oscillation analyses. The measured flux-averaged cross section agrees with GENIE 3.2.0 predictions within 8%.
Takeaway Reduces a leading systematic for DUNE. No evidence for the low-energy excess pattern reported by MiniBooNE.
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NuFIT 6.0: an updated global determination of three-neutrino oscillation parameters
NuFIT 6.0 incorporates the post-2024 T2K-II, NOvA full-exposure, and JUNO first 38 days into a unified three-flavour fit. Best fit (NO): sin²θ₁₂ = 0.308, sin²θ₁₃ = 0.0220, sin²θ₂₃ = 0.572, δ_CP = -1.98, ∆m²₂₁ = 7.43 × 10⁻⁵ eV², ∆m²₃₂ = +2.508 × 10⁻³ eV². NO preference: 3.1σ.
Takeaway Reference parameter set for next-generation phenomenology and detector design until JUNO-NO closure.
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Improved limits on neutrinoless double-β decay from the LEGEND-200 first physics run
LEGEND-200 sets a half-life lower limit of T₁/₂ > 1.6 × 10²⁶ yr (90% C.L.) for the 0νββ decay of ⁷⁶Ge after one year of operation, corresponding to ⟨m_ββ⟩ < 70–161 meV depending on the nuclear matrix element.
Takeaway Halfway to design sensitivity. Tonne-scale LEGEND-1000 begins assembly in 2027.
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First reactor antineutrino measurement with JUNO
JUNO reports its first 38 days of physics data, observing 1,224 inverse-beta-decay candidates with an energy resolution of 3.07% at 1 MeV. The measured spectrum is consistent with the expected three-flavour oscillation pattern.
Takeaway On-target energy resolution achieved earlier than expected; mass-ordering sensitivity remains on the published timeline.
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Commissioning of KamLAND-Zen 1000 with 1.7 t of enriched ¹³⁶Xe
KamLAND-Zen 1000 begins physics with 1.745 t of ¹³⁶Xe-loaded liquid scintillator, double the Zen-800 mass. Background rates from spallation backgrounds match projection within 10%; first 0νββ-half-life sensitivity projection: T₁/₂ > 5 × 10²⁶ yr at 5 yr exposure.
Takeaway Inverted-ordering parameter region fully covered within 5 years if backgrounds hold; design well within reach.
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Joint analysis of T2K and NOvA muon-neutrino disappearance and electron-neutrino appearance data
Combined fit of all currently published T2K and NOvA data prefers normal mass ordering at 2.5σ and excludes the CP-conserving values δ_CP = 0, π at 1.9σ in NO. Best-fit δ_CP = −1.85 (NO).
Takeaway Mild but persistent tension between the two experiments' preferred octants of θ₂₃ remains unresolved.
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Combined mass-ordering preference from JUNO, T2K, NOvA, IceCube/DeepCore and Super-Kamiokande
A combined global fit including the most recent T2K, NOvA, atmospheric, and the first 38 days of JUNO data shifts normal-ordering preference to 3.1σ and pins ∆m²₃₂ to (2.508 ± 0.022) × 10⁻³ eV² in NO, the tightest mass-squared-splitting determination on record.
Takeaway Mass ordering crosses the 3σ-evidence threshold for the first time in a joint analysis.
March 2026
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Final CUORE result on neutrinoless double-beta decay of ¹³⁰Te with 3 t·yr exposure
CUORE's final analysis with the full 3 t·yr ¹³⁰Te exposure sets a half-life lower limit T₁/₂ > 4.7 × 10²⁵ yr at 90% CL, corresponding to ⟨m_ββ⟩ < 60–200 meV depending on the nuclear matrix element model. Bolometric resolution achieved 5 keV FWHM at the 2528 keV Q-value.
Takeaway CUORE legacy bound; CUPID-Mo follows with same cryostat in 2027.
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Cosmological neutrino-mass bound from DESI BAO and CMB anisotropies
A combined analysis of DESI Year-1 BAO data with Planck CMB temperature and polarization spectra yields Σm_ν < 0.072 eV at 95% C.L. assuming flat ΛCDM, in mild (≤ 2σ) tension with terrestrial lower bounds in the inverted ordering.
Takeaway If the bound holds, the inverted mass ordering becomes increasingly disfavoured.
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Updated global constraints on neutrino non-standard interactions from oscillation and scattering data
A combined fit of all relevant oscillation, COHERENT, and atmospheric-IceCube data tightens NSI parameter bounds to |ε_ee - ε_μμ| < 0.05, |ε_eτ| < 0.04, |ε_μτ| < 0.012 at 90% CL — the tightest model-independent constraints on flavour-changing NSI to date.
Takeaway Closes much of the parameter space invoked to soften T2K + NOvA δ_CP tension; LMA-Dark solution further disfavoured.
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Status report: completion of the DUNE far-detector module-1 cryostat
A technical report on the assembly, leak-checking, and qualification of the first DUNE far-detector cryostat module at SURF. Total mass capacity: 17.5 kt of liquid argon. Final commissioning expected 2027.
Takeaway Civil works on schedule; cryogenics installation begins Q3 2026.
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T2K-II first physics: improved beam-power running and updated δ_CP fit
First T2K-II analysis with the upgraded ND280 and 760 kW J-PARC beam reports 218 ν_e candidates against 188 ± 14 expected. The combined fit with the legacy T2K dataset gives sin²θ₂₃ = 0.55 (NO) and δ_CP excluding 0 and π at 90% CL; mass-ordering preference NO at 2.1σ.
Takeaway Upgraded ND280 systematic budget halved relative to T2K-I. Hyper-K commissioning starts next year.
February 2026
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IceCube point-source analysis of NGC 1068 with 13 years of data
A 13-year cascade-event analysis confirms the 2022 NGC 1068 evidence at 5.1σ, establishing the first 5σ point-source detection of an active galactic nucleus in TeV neutrinos. Best-fit single-power-law spectral index γ = 3.2, harder than the diffuse-flux spectrum.
Takeaway Discovery threshold crossed; the first AGN to be confirmed as a TeV-neutrino emitter.
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Direct neutrino-mass measurement with the full KATRIN tritium dataset
KATRIN reports its final-target sensitivity result combining KNM-1 through KNM-6 measurement campaigns, placing an upper bound of m_β < 0.32 eV / c² at 90% C.L. — the world's tightest model-independent neutrino-mass limit.
Takeaway Approaching the design sensitivity of 0.2 eV. Cosmological-direct tension narrows but remains.
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First atomic-tritium spectrum from Project 8 cyclotron-radiation emission spectroscopy
Project 8 reports the first frequency-domain tritium endpoint measurement using cyclotron-radiation emission spectroscopy on a 100 cm³ atomic-tritium source. Phase-II target sensitivity m_β < 2 eV achieved; Phase-III roadmap projects m_β < 40 meV with the full atomic source.
Takeaway Demonstrates frequency-domain endpoint spectroscopy as a scalable alternative to electrostatic spectrometers.
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KM3NeT/ARCA observation of a 220-PeV neutrino-induced muon track
A single up-going muon track with reconstructed energy 220 +110/-50 PeV is observed in 287 days of KM3NeT/ARCA data. The arrival direction is consistent with the southern sky and inconsistent with any known γ-ray source, making it the highest-energy neutrino-induced muon ever recorded.
Takeaway Single event but at extraordinary energy; statistical significance for a new astrophysical population pending Gen-2 deployment.
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Constraint on the diffuse supernova neutrino background from Super-Kamiokande Gd-loaded data
Super-K with 0.03% gadolinium loading reports the most stringent existing limit on the integrated DSNB ν̄_e flux above 9.3 MeV: Φ_DSNB < 2.4 cm⁻²s⁻¹ at 90% CL. The result corresponds to neutron-tagging efficiency ~80%, a factor of 3 improvement over the pre-Gd analysis.
Takeaway 5–10σ discovery within reach by Hyper-K's first decade if optimistic supernova-rate models hold.
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Constraints on light sterile neutrinos from the BEST gallium experiment
A re-analysis of the BEST chromium-source dataset including updated cross sections and reactor flux constraints reports a deficit consistent with sterile-neutrino oscillations at Δm² ≈ 1 eV² and sin²2θ ≈ 0.4.
Takeaway Strengthens the long-standing gallium anomaly. Tension with reactor and atmospheric data continues.
January 2026
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Joint Planck CMB + DESI BAO + DES-Y3 weak-lensing constraint on Σm_ν
A joint analysis of Planck PR4 CMB temperature and polarization spectra, DESI Year-1 BAO measurements, and DES-Y3 cosmic-shear yields Σm_ν < 0.061 eV at 95% CL assuming flat ΛCDM. The bound is in 2.4σ tension with the inverted ordering minimum Σm_ν = 0.10 eV.
Takeaway Cosmology now actively disfavours the inverted ordering; consistency with terrestrial data via a sum-rule open question.
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First search for ¹³⁰Te neutrinoless double-beta decay with SNO+
SNO+ Phase I, with 0.5% natural-abundance ¹³⁰Te dissolved in 780 t of liquid scintillator, reports a 90% CL lower limit T₁/₂ > 1.3 × 10²⁵ yr from 138 days of physics data. Phase-II will increase the loading to 2% and projects T₁/₂ > 2 × 10²⁶ yr.
Takeaway First-light demonstrates the loaded-scintillator technology; baseline for the upgraded Phase II programme.
December 2025
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Constraints on a fourth-generation light sterile neutrino from KATRIN tritium spectroscopy
A model-independent kink-search in the full KATRIN dataset to date excludes the eV-sterile region preferred by the gallium and reactor anomalies at 95% CL across 0.1–40 eV mass range. Independent of beam, reactor and atmospheric data.
Takeaway Tritium-endpoint kinematics joins the catalogue of methods disfavouring the canonical eV-sterile hypothesis.
October 2025
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Final STEREO sterile-neutrino search at the ILL highly-enriched-uranium reactor
STEREO's 119 reactor-on-day final dataset shows no L/E-dependent oscillation pattern in 2.5–7 m baselines and excludes the canonical eV-sterile parameter region of the reactor antineutrino anomaly at >99.9% CL across the full mass-mixing space favoured by the original anomaly.
Takeaway Closes the reactor short-baseline programme cleanly; SBND is now the lead sterile probe via the appearance channel.
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