{"id":"84d3c842-14a1-4f88-ab20-6d4349856fc3","arxiv_id":"2512.10744","paper_version":2,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":2,"one_line_summary":"A projected joint IceCube+KM3NeT Galactic-neutrino analysis could constrain quasi-Dirac mass splittings near 10^-14-10^-12 eV^2 and nu3-to-nu1 decay rates above 5e-13 eV^2 at 90% CL.","lead":"High-energy neutrinos from the Milky Way could carry imprints of new physics that makes neutrinos split into near-identical partners or decay over galactic distances. This paper forecasts that a joint IceCube and KM3NeT analysis by 2035 could probe such effects in a distance-over-energy window no other experiment reaches.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"TANDEM model dependence is the load-bearing link; Appendix B only varies gas maps, leaving the CR source distribution and spectral shape of the central emission model unvalidated.","rationale":"The reader's weakest_assumption pinpoints TANDEM as the unvalidated, self-cited foundation of the forecast. I reached the same conclusion independently after tracing the analysis chain: Section III introduces TANDEM as the model of diffuse Galactic neutrino emission; Section V's central numbers are direct outputs of integrating TANDEM against BSM probabilities. Appendix B is the paper's own sensitivity check, but it varies only gas maps; it leaves the CR source distribution and spectral shape unvaried. Therefore the forecast's robustness to the most uncertain ingredient is not established. I do not think this warrants changing the reader's CONDITIONAL verdict--the method is internally coherent and the authors are transparent about assumptions--but it does mean the paper should not be read as a model-independent sensitivity forecast. The internal abstract/Section V inconsistencies the reader also flagged are real but secondary: they concern reporting of the numbers, not the physics mechanism. A concrete replacement-model computation would settle whether the TANDEM assumption is actually decisive or whether the sensitivity is robust across the plausible model space.","tokens_in":17297,"tokens_out":10294,"duration_ms":109792,"concrete_test":"Replace TANDEM with an independent public diffuse Galactic neutrino template (e.g., the GALPROP-based model of Ref. [63] or the Schwefer et al. model of Ref. [60]) and rerun the full combined IceCube+KM3NeT Asimov analysis exactly as in Eq. (4). In parallel, within TANDEM vary the CR source distribution (e.g., pulsars vs. SNR remnants) and the magnetic-field model. If the 90% CL QD interval changes by more than ~0.3-0.5 dex at either endpoint, or the nu3->nu1 alpha_3 bound changes by more than a factor of ~3, the stated central sensitivities are model-dominated and the paper's headline claims require re-scoping to conditional forecasts.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The forecast is built entirely on TANDEM (Ref. [64], cited as 'upcoming' and by the same group), which supplies the four-dimensional emissivity F_beta integrated against BSM survival probabilities in Eq. (3) and Appendix A. Every sensitivity curve in Fig. 6 therefore inherits TANDEM's spatial and spectral assumptions. The profile pull xi in Eq. (4) absorbs only an overall normalization shift; it cannot correct for errors in the direction-dependent baseline distribution or spectral shape that drive the L/E smearing. Appendix B checks robustness only across four gas maps, explicitly not varying the CR source distribution (assumed to follow SNRs), the CR propagation/magnetic-field model, or the hadronic interaction model. Since Ref. [64] is unpublished and no code/data are provided, the central numbers--delta m^2 in [3e-14,1e-12] eV^2 and alpha_3 > 5e-13 eV^2 for nu3->nu1--cannot be independently reproduced or falsified. If TANDEM's spatial/spectral model is wrong in the relevant directions, these sensitivity intervals could shift substantially or disappear. This is the weakest load-bearing link in an otherwise internally coherent statistical framework.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper forecasts the sensitivity of IceCube and KM3NeT/ARCA to two beyond-Standard-Model propagation effects—quasi-Dirac (QD) neutrino oscillations and neutrino decay—using the upcoming TANDEM model of diffuse Galactic neutrino emission. The authors compute direction- and energy-dependent survival probabilities, build a binned Poisson likelihood with an unconstrained Galactic-flux normalization pull, and present Asimov 90% CL sensitivities for a projected 2035 analysis (23 years of IceCube cascades and 5 years of KM3NeT tracks). They report sensitivity to QD squared-mass splittings around δm^2 ∈ [3×10^-14, 10^-12] eV^2 and to ν3→ν1 visible decay for α3 > 5×10^-13 eV^2, while invisible ν3 decay is not sensitive. The analysis emphasizes complementarity between cascade and track channels for decay scenarios.","tokens_in":17612,"tokens_out":3924,"duration_ms":44533,"significance":"If the reported sensitivities are correct, Galactic neutrinos would open a new L/E window near 10^13 km/GeV, complementary to solar, atmospheric, supernova, and diffuse astrophysical constraints, and could discriminate among neutrino mass models. The paper's strengths include a physically motivated direction-resolved treatment of propagation, a standard likelihood framework with a profiled normalization, explicit use of realistic detector responses, and a robustness check over four gas maps (Appendix B). The claimed complementarity between IceCube cascades and KM3NeT tracks in the decay case is well illustrated and is a useful contribution. However, the central numerical results are stated inconsistently across the abstract, introduction, and main text, and the entire forecast rests on an unpublished, same-group emission model (TANDEM) whose spatial and spectral degrees of freedom are only partially varied.","major_comments":[{"comment":"The paper reports three different sets of central sensitivities. The abstract gives δm^2 ∈ (10^-13.6, 10^-12.3) eV^2 and m/τ > 10^-12.8 eV^2; the introduction gives δm^2 ∈ (10^-13.5, 10^-11.9) eV^2 and m/τ > 10^-12.3 eV^2; Section V gives δm^2 ∈ [3×10^-14, 10^-12] eV^2 for the combined analysis and α3 > 5×10^-13 eV^2 for ν3→ν1 decay. These differ by up to ~0.5 dex in the upper end of the QD range and in the decay limit (10^-12.3 vs 10^-12.8). The body's numbers should be taken as definitive; the abstract and introduction must be reconciled with them. This is not a cosmetic issue because the claimed discovery/exclusion reach is the paper's central result.","section":"Abstract; Introduction; Section V"},{"comment":"The entire signal prediction is built on the TANDEM model, which provides the four-dimensional emissivity Fβ integrated in Eq. (3). Ref. [64] is cited as 'upcoming' and is authored by the same group; no code or tabulated model is provided. Appendix B varies only the gas maps, not the cosmic-ray source distribution, CR propagation/magnetic-field model, or hadronic interaction model. These are precisely the inputs that set the direction-dependent baseline distribution and spectral shape—the quantities that drive the L/E smearing and, hence, the sensitivity contours in Fig. 6 and B.2. The profile pull ξ in Eq. (4) only rescales the total normalization and cannot correct for a wrong spatial or spectral shape. I request a quantitative validation of TANDEM against the observed IceCube Galactic plane data (e.g., Ref. [14]) or a comparison with at least one independent CR distribution and CR pro","section":"Section III, Eq. (3); Appendix B; Ref. [64]"},{"comment":"The ν3→ν1 visible-decay analysis is restricted to the quasi-degenerate limit, where the decay-product energy spectrum is a delta function (Eq. A2). This is acknowledged, but the sensitivity quoted in Section V (α3 > 5×10^-13 eV^2) is derived entirely in this limit. Since the absolute neutrino mass scale is not known (KATRIN only provides an upper bound), the analysis should either quantify how the sensitivity degrades for lower mass scales or clearly state that the quoted reach applies only to this corner of parameter space. As written, a reader could overinterpret the bound as general for ν3→ν1 decay.","section":"Appendix A; Section V"}],"minor_comments":[{"comment":"The caption says 'Galactic latitude ℓ and longitude b'; ℓ and b are conventionally Galactic longitude and latitude, respectively. Please correct the ordering.","section":"Figure 3 caption"},{"comment":"The sentence 'our sensitivities to do not vary greatly' contains an extra 'to' and should read 'our sensitivities do not vary greatly'.","section":"Appendix B, text"},{"comment":"Since TANDEM is the central input, the paper should state whether a preprint or public code release is planned and, ideally, include a link or a version identifier. This is important for reproducibility.","section":"Ref. [64]"},{"comment":"The notation N_i^G versus μ_i^G is a little confusing: N is used for the BSM signal prediction while μ is the SM signal. A short sentence explicitly defining 'N' and 'μ' in the text would improve readability.","section":"Section IV, Eq. (4)"}],"recommendation":"major_revision","confidential_remarks":"The paper is promising and the statistical framework appears sound, but the inconsistent central numbers must be fixed, and the TANDEM dependence needs stronger validation or a clear caveat. Given that Ref. [64] is an upcoming same-group paper, the reproducibility concern is real though not disqualifying; I would encourage the editor to ask for a version of the manuscript that either includes the TANDEM validation or makes the model public. If the authors address the major comments, the paper could become suitable for publication."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Short version: this paper is worth a careful read. It is the first sensitivity forecast for Galactic diffuse neutrinos to quasi-Dirac mass splittings and neutrino decay, and the core idea—using the direction-dependent line-of-sight baselines of the Milky Way to open an L/E window near 10^13 km/GeV—is genuinely new and interesting. The cascade+track complementarity argument is also well made, and the statistical framework (binned Asimov likelihood, profiled flux normalization) is standard and competently executed. Appendix B's check across four gas maps is a real attempt at robustness, and it shows the qualitative phenomenology is fairly stable.\n\nThe soft spots are real but not fatal. The central numbers change depending on where you look: abstract gives delta m^2 in (10^-13.6, 10^-12.3), introduction says (10^-13.5, 10^-11.9), Section V says [3e-14, 1e-12]. That is not a rounding error; the authors need to reconcile. Similarly the abstract's decay reach (m/tau > 10^-12.8 eV^2) does not match Section V, which says invisible decay is not sensitive at 90% CL and only nu3->nu1 reaches alpha3 > 5e-13 eV^2. A reader should not have to reverse-engineer which number is the result.\n\nThe bigger issue is the TANDEM model. The entire forecast is built on it, and it is cited as 'upcoming' by the same group with no code or data released. The stress-test note is right: Appendix B varies gas maps only. It does not vary the CR source distribution, the propagation model, or the hadronic interaction model. The flux normalization pull absorbs only an overall scale; it cannot correct for direction-dependent errors in the L/E baseline distribution. So the sensitivity intervals could shift if TANDEM's spatial/spectral model is wrong. That said, this is a forecast, not a measurement, and the model-dependence is a standard hazard in this kind of study. The authors are transparent that unresolved sources and normalization uncertainties could change things. I don't see a fatal flaw.\n\nMy bottom line: the paper deserves a serious referee. The novel L/E window and the complementarity point are solid. But the referee should insist the authors harmonize the numbers, provide more detail or a public version of TANDEM, and ideally add a robustness test that varies the CR source distribution, not just gas maps. If those are fixed, it is a solid contribution to the neutrino phenomenology literature.","headline":"Useful and genuinely new sensitivity forecast for Galactic neutrinos to quasi-Dirac and decay, but the headline numbers rest on an unpublished TANDEM model and the paper reports inconsistent central values.","tokens_in":18116,"tokens_out":3226,"would_cite":false,"duration_ms":34390,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"A joint IceCube–KM3NeT analysis of Galactic neutrinos is forecast to be sensitive to quasi-Dirac mass-squared splittings in [3e-14, 1e-12] eV^2 and to nu3->nu1 decays with alpha3 > 5e-13 eV^2 at 90% confidence.","keywords":["neutrino astronomy","quasi-Dirac neutrinos","neutrino decay","Galactic plane","IceCube","KM3NeT","ultra-long baseline propagation","diffuse Galactic neutrino emission"],"falsifier":"The cleanest check is the direction-resolved energy spectrum of the Galactic plane: if, in the combined 2035 sample, no spectral distortion appears at the level predicted for delta m^2 = 1e-13 eV^2 or alpha3 = 1e-13 eV^2 (per-bin deviations of order the statistical uncertainty shown in Figs. 3-5), the central sensitivity claim is falsified. An independent map of the Galactic cosmic-ray distribution from gamma-ray or radio data would also settle whether the assumed emission geometry is correct before invoking new physics.","tokens_in":17220,"feed_emoji":"🔭","tokens_out":5522,"duration_ms":58693,"temperature":0.7,"pith_summary":"This paper argues that the Milky Way's diffuse neutrino glow, recently detected by IceCube, can serve as a neutrino-physics laboratory at distance-over-energy scales around 10^13 km/GeV, a regime untouched by solar, atmospheric, or long-baseline experiments. It forecasts that combining IceCube cascade events with KM3NeT track events by 2035 will be sensitive, at 90% confidence, to quasi-Dirac mass-squared splittings between 3e-14 and 1e-12 eV^2, and to nu3-to-nu1 decay with decay parameter alpha3 above 5e-13 eV^2. The key is that the emission model provides the three-dimensional distribution of neutrino sources along each line of sight, so the path-length spread in the Galaxy turns the usual oscillation or decay formula into a direction-dependent spectral distortion. If the forecast is right, a global neutrino-telescope network opens a new window on neutrino mass models, complementing existing bounds.","feed_headline":"Galactic neutrinos could test mass splits down to 3e-14 eV^2","feed_subtitle":"Combining IceCube cascades with KM3NeT tracks probes quasi-Dirac and decaying-neutrino models on scales beyond all others.","key_machinery":"The machinery is the TANDEM emission model: a spatial-spectral model of diffuse Galactic neutrino emissivity that gives the expected neutrino production rate per unit volume along any line of sight. The paper integrates this emissivity against the quasi-Dirac oscillation probability (cos^2 of the L/E-dependent phase) and the exponential decay survival probability, yielding a direction-dependent weighting that smears what would otherwise be a clean L/E oscillation into a spectral distortion. The analysis then uses a binned Poisson likelihood with a profiled overall flux normalization; this profiled normalization is what makes the track-cascade complementarity essential for detecting decay.","core_discovery":"On the paper's own terms, the central claim is that the diffuse Galactic neutrino flux, measured with cascade events at IceCube and track events at KM3NeT/ARCA, probes new propagation physics at L/E around 10^13 km/GeV. A combined analysis would exclude quasi-Dirac mass-squared splittings in [3e-14, 1e-12] eV^2 and nu3-to-nu1 decays with alpha3 > 5e-13 eV^2 at 90% confidence, while invisible nu3 decay remains out of reach at that significance. The signal is a direction- and energy-dependent disappearance of the flux, produced by the wide spread of source baselines inside the Galaxy. The two detector channels are complementary because cascades offer good energy resolution but poor angular res","pith_inferences":["If gamma-ray observations could anchor the overall Galactic flux normalization, the analysis would extend into the regime where BSM effects become pure normalization shifts (delta m^2, alpha above about 1e-11 eV^2), broadening the probe beyond shape distortions.","A discovery of individual Galactic neutrino point sources would provide well-defined baselines and far less L/E smearing, potentially sharpening the same quasi-Dirac and decay signatures beyond what the diffuse flux can offer.","In the quasi-degenerate visible-decay limit, the nu3-to-nu1 channel predicts a low-energy bump in the nu1 flux; a dedicated low-energy analysis could test this prediction independently of the 90% sensitivity projection.","The same spatially resolved emission model could be applied to other distance- and energy-dependent propagation effects, such as neutrino secret interactions or Lorentz-violating oscillations, which would imprint different direction-dependent spectra."],"forward_implications":["A 2035 combined analysis would place the first competitive constraints on quasi-Dirac splittings in the band between solar bounds and SN1987A constraints, reaching down to about 3e-14 eV^2.","The same data would probe nu3-to-nu1 decay with alpha3 above about 5e-13 eV^2, overlapping the solar 3-sigma bound and testing the quasi-degenerate limit of Majoron models.","Invisible nu3 decay is not expected to be detectable at 90% confidence with the assumed exposures.","Because the signal is direction- and energy-dependent, a measurement of the Galactic plane's spectral shape with good angular and energy resolution is itself the physics test; the combined analysis exploits each detector's strengths.","The sensitivity holds up across the four gas-map models tested in the appendix, even though the three-dimensional emission profiles differ substantially."],"fun_headline_variants":["Galactic neutrinos test neutrino decay and quasi-Dirac mass splits","IceCube+KM3NeT hunt for neutrino mass and decay signatures","Galactic flux may reveal mass splittings at 3e-14 eV^2 scale","Neutrino decay and quasi-Dirac models probed by galactic neutrinos"],"cache_read_input_tokens":2304,"weakest_assumption_plain":"The forecasts rest on TANDEM, a still-unpublished model by the same group that determines where and how brightly the Galaxy emits neutrinos; if the cosmic-ray source distribution, gas maps, or absolute normalization are wrong, the direction-dependent smearing that produces the sensitivity changes, and the paper varies only gas maps, not the cosmic-ray distribution or the overall normalization.","fun_headline_variants_meta":{"raw":{"variants":["Galactic neutrinos test neutrino decay and quasi-Dirac mass splits","IceCube+KM3NeT hunt for neutrino mass and decay signatures","Galactic flux may reveal mass splittings at 3e-14 eV^2 scale","Neutrino decay and quasi-Dirac models probed by galactic neutrinos"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000588,"raw_usage":{"total_tokens":2604,"prompt_tokens":759,"completion_tokens":1845,"prompt_tokens_details":{"cached_tokens":256},"prompt_cache_hit_tokens":256,"prompt_cache_miss_tokens":503,"completion_tokens_details":{"reasoning_tokens":1760}},"tokens_in":503,"tokens_out":1845,"duration_ms":13403,"temperature":1.0,"reasoning_tokens":1760,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-03T17:02:42.215476+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"The cleanest check is the direction-resolved energy spectrum of the Galactic plane: if, in the combined 2035 sample, no spectral distortion appears at the level predicted for delta m^2 = 1e-13 eV^2 or alpha3 = 1e-13 eV^2 (per-bin deviations of order the statistical uncertainty shown in Figs. 3-5), the central sensitivity claim is falsified. An independent map of the Galactic cosmic-ray distribution from gamma-ray or radio data would also settle whether the assumed emission geometry is correct before invoking new physics.","supporting_citations":[],"review_version":1}