Scenario · falsification test · chains three tools

Background-Free: From Multiplet to Campaign

Three tools trace Paper A's T6 falsification spine in order: the Poisson accounting that decides whether a neutrino multiplet is background-free, the multi-messenger coincidence score that would corroborate it, and the astrometric follow-up campaign the result justifies. A quiet detector field and a busy one lead to different downstream campaigns.

No backend · No tracking · Works offline · v1.0 · 2026-07-23
⚙ Pick a detector environment

Both environments run the same three-tool chain; only the background rate/cone/window in Step 1, the transient brightness in Step 2, and the resulting campaign choice in Step 3 change.

01
neutrino-multiplet-fa · Paper A §7, T6 · background-only Poisson accounting
Is the multiplet background-free?

The T6 kill condition asks how often an atmospheric-neutrino background alone throws an accidental multi-track coincidence inside a search cone, at a given detector rate, cone radius, coincidence window, and multiplicity threshold. In the quiet field (10² yr⁻¹ background, 1° cone, 100 s window, ≥3-fold) the expected count over 10 yr of livetime is 5.91×10⁻¹⁷, background-free by many orders of magnitude even after a ×10 trials-factor penalty. In the busy field (10⁴ yr⁻¹ background, 3° cone, 10⁴ s window, ≥2-fold) the same accounting gives 2.97×10⁻¹, which is no longer ≪1, and a ×10 trials-factor penalty for scanning multiple window durations pushes the expected count to ∼3, past the point where a single coincidence can be called background-free on its own.

Open Neutrino Multiplet Calculator → Theoretical (order-of-magnitude background estimate)
Step payoff
A background-free claim on its own is not evidence of anything, only the absence of one obvious way to explain a coincidence away. Step 2 asks whether independent channels corroborate the same source.
02
multi-messenger-alert · LISA / Fermi-LAT / CTA / KM3NeT coincidence score
Do other messengers corroborate?

The same ω Cen IMBH mass range feeds an EMRI gravitational-wave calculation and, for a posited transient, a gamma-ray and neutrino flux estimate against each instrument's threshold. At OC's distance, any transient within the tool's allowed source-power range (10³²–10⁴⁸ W) clears the Fermi-LAT, CTA, and KM3NeT thresholds by many orders of magnitude, so both environments here return the tool's maximum 4/4 coincidence score, publish-worthy on the tool's own scoring, false-alarm rate < 1 per 10⁶ yr. What does change between them is the EMRI itself: the quiet field's 8,128 M☉ hole with a 1.4 M☉ companion gives strain h₀ = 5.1×10⁻¹⁸, the busy field's lighter 6,026 M☉ hole with a 10 M☉ companion gives h₀ = 3.7×10⁻¹⁷ (a heavier companion partly compensating for the smaller primary); both sit far above LISA's SNR = 8 threshold regardless.

Open Multi-Messenger Alert Simulator → Established (GR EMRI, Landauer-independent) Theoretical (transient flux model)
Step payoff
Corroboration strength here turns out not to distinguish the two environments; both clear every channel the tool checks. The real difference upstream, Step 1's background test, is what should drive the Step 3 campaign choice, not the coincidence score.
03
observing-campaign-planner · instrument, science goal, and campaign feasibility
What follow-up campaign does the result justify?

Since Step 2's corroboration score does not distinguish the two environments, the campaign choice tracks Step 1's background result instead. The quiet field's background-free claim justifies going straight at confirmation: ELT-MICADO targeted at confirming any central mass (3σ), feasible, a required ensemble precision of 115.9 μas/yr against ELT's 80 μas single-epoch precision over 500 stars, 3 epochs, 1.5 telescope-hours, 1 semester. The busy field's marginal background result argues for a broader independent line of evidence before leaning on the neutrino channel at all: Roman Space Telescope aimed at discovery-level detection (5σ) over a larger 2,000-star sample, also feasible, 95.1 μas/yr required against Roman's 15 μas precision, 3 epochs, 0.75 telescope-hours, 1 semester. Neither campaign is expensive at these fiducials; the difference is which goal the background result can support on its own.

Open Observing Campaign Planner → Established (astrometric precision scaling)
Step payoff · the chain closes
The chain runs from a background test, through corroboration, to a concrete telescope proposal, and the corroboration step turned out to be uninformative between these two environments at OC's distance: it is the background test in Step 1 that ends up doing the work of choosing the campaign.
⚖ Why these three tools are the argument's spine

Paper A's T6 falsification test is built to fail loudly: it exists so that a claimed detection can be checked against the boring explanation first. The three tools here follow that same discipline in order, ruling out background, checking for independent corroboration, and only then sizing a follow-up campaign around whatever corroboration actually exists.

The two environments show that a background-free claim is a necessary first gate, not the whole case, though corroboration does not always add information on top of it: at OC's distance, any posited transient within the tools' allowed power range clears every gamma-ray and neutrino threshold checked here, so the coincidence score is 4/4 regardless of which environment is chosen. The environments still diverge sharply at Step 1, and that divergence is what should drive the Step 3 campaign choice.

For the full T6 derivation and Table 2's instrument response requirements, see the companion paper this chain draws from at the papers index. For a different chain through the same decision-theory family, see Scenario: Migrate or Stay.

EPISTEMIC TIERS: Established = peer-reviewed physics within the standard formulation. Debated = active disagreement in the published literature. Theoretical = published framework, awaiting decisive observation. ✦ Speculative = published conjecture, no strong empirical support yet.