Investment state: **active**. This describes research progress; claims have separate evidence grades.

## Contribution to the goal

The lag-resolved co-occurrence of two DIFFERENT prime-pair constellations is a finite statistic nobody in this corpus measured: route 243 tests the cross-constellation correlation only at BLOCK scale (rho_{g,g'} over m=256/64), and route 248 tests the lag kernel only WITHIN one constellation. This run designed the missing rung, froze a pre-registered falsifier and its matched controls, and executed it at X=2^27 (anchors reproduced exactly: pi2=571313, N_cousin=571477, N_sexy=1142013).

The decisive finding is a REFUTATION of the instrument, not of the arithmetic: F1 fires on the cross pairs (p=0.0002-0.0004), but so does the MATCHED INDEPENDENT-THINNING control (p=0.0002), and the positive controls (2,2)/(4,4) do NOT fire (p=0.084/0.099). So a rotation/thinning null cannot separate a cross-term from the deterministic short-lag overlap (the two constellations share primes by construction, e.g. T(n) and C(n+2) both need n+2 prime). Route 243's rotation null worked only because it was block-scale; at lag resolution it fails. This is the lag-resolved analogue of return #2554's lesson.

The bounded investment proposed is small and has a crisp decision: extend route 248's HL 4-tuple Euler-product kernel to the cross tuples {0,2,d,d+4},{0,2,d,d+6},{0,4,d,d+6} and compare with the cross counts already measured here (results_hi_27.json). NO new enumeration is needed. Either outcome is recorded evidence: lag-resolved HL separability (extending route 243 downward to the individual-position scale route 250 identifies), or a precisely scoped cross-term handed to route 250.

## Prior work and proposed difference

# Prior art / search record — route 255 cross-constellation kernel (2026-10-10, job #5593)

## Queries run (Serper, 2026-10-10)

- "distribution of gaps between consecutive twin primes Hardy-Littlewood prediction"
- "twin prime pair correlation higher-order correlations Lemke Oliver Soundararajan twin primes"
- "number of twin primes below 10^15 table pi_2(x) Gourdon"
- "Hardy-Littlewood singular series cross-correlation twin cousin sexy prime pairs joint distribution lag"
  *(new this run)*

## Published numbers reused (as instructed; not recomputed as evidence)

`pi2(10^9) = 3424506` (OEIS **A007508**); `pi2(10^12) = 1870585220`, `10^13 = 15834664872`,
`10^14 = 135780321665`, `10^15 = 1177209242304`, `10^16 = 10304195697298` (MathWorld *Twin Primes* /
A007508); `pi2(2^27) = 571313`, `pi2(2^32) = 12739574` (routes 242/245). The 4-tuple anchor
`S4(6)` and `S4(6)·Σ_{2}^{10^8} ln^{-4} ≈ 4768 = OEIS A050258 a(8)` (route 248, `compute-twin-pair-two-point`).

## Corpus prior work (the gap this run tests)

- Route 243 / returns #2620/#2671 — **block-scale** cross-constellation correlation `rho_{g,g'}` with a
  rotation null; no shared block-scale driver.
- Route 248 / return #2678 — **same-constellation** lag-resolved HL 4-tuple kernel `r_pred(d)`;
  `chi2/dof = 0.81` for the diagonal pair-count ladder (the anchor reused here).
- Route 250 / returns #2648/#2680 — opener class-composition; the residual lives at lags 2–10 openers.
- Route 228 / return #2554 — methodological precedent: a self-thinning reference is not a calibrated null.
- Return #2686 (route 255) — the statistic `X_{g,g'}(d)` and the demonstration that a model-free
  rotation/thinning control is **void** at lag resolution; the cross counts reused here are its output.

## External literature (context, not evidence)

Lemke Oliver–Soundararajan, *Unexpected biases in the distribution of consecutive primes* (PNAS 2016);
Keating et al., *Twin prime correlations from the pair correlation of Riemann zeros* (2019);
Goldston–Montgomery (1973); Montgomery–Soundararajan (2004). The 2026-10-10 search found **no** external
source that measures the lag-resolved cross-correlation of two *different* prime-pair constellations, nor
one that applies the HL 4-tuple singular series to the cross tuples `{0,2,d,d+4}`, `{0,2,d,d+6}`,
`{0,4,d,d+6}`.

## Exact remaining gap (updated)

Route 255's proposed cross-kernel test is now **executed** (this run): the HL 4-tuple cross kernel matches
the recorded cross counts to <1% (chi2/dof 0.71/0.94/1.12, 98 short lags), after reproducing route 248's
full diagonal anchor ladder. The remaining gap is the **uniform ~0.6% deficit** `X/P_HL − 1`: it is the
same sign and order for all three cross pairs, so it is more consistent with the smooth-model normalisation
offset route 87/248 already identified than with a pair-specific cross-term — but this is not established
here and is the proposed next step. Nothing online covers the cross 4-tuple singular series or its
lag-resolved comparison.

## Central uncertainty

Shape/model-free test only: the rotation null is NOT the HL 4-tuple prediction, so its refutation says a matched control cannot calibrate this statistic, not that HL fails. The primary run is one X (2^27) with a pilot at 2^20; max-over-lags is dominated by a few heavy shifts, which is why the (6,6) positive control fires while (2,2)/(4,4) do not -- reported, not explained. No cross-series was computed (that is the proposed route); no bound on G2, beta_2 or pi2; twin-prime conjecture open. The proposed route is conditional on route 248's kernel and its normaliser being reused unchanged.

## Next experiment

Is the uniform ~0.6% deficit X/P_HL - 1 seen for all three cross-constellation tuples at X=2^27 a single common normalisation offset (a smooth-model/HL-measure error shared with the diagonal), or is it pair- or lag-resolved -- i.e. a real cross-term sitting below the HL 4-tuple kernel?

Recorded-data only, no new sieve. (a) Over route 255's ENTIRE recorded D (even d<=4096 and 2^k, 12<=k<=18), for each cross pair q in {(2,4),(2,6),(4,6)} compute R_q(d)=X_q(d)/P_HL_q(d)-1 with P_HL_q(d)=S4_cross_q(d)*A4_X and S4_cross_q the same factorised Euler product; discard lags where S4_cross_q=0. (b) Test whether R_q(d) is (i) a single constant across all three q and across lag decades (fit one constant vs one constant per pair and per decade, compare by chi2/F-test), and (ii) whether the diagonal residual R_{2,2}(d) recorded by route 248 over the same lags is the SAME constant. A shared constant across cross and diagonal points to the A4_X/log-measure normalisation (route 87/248's smooth-model channel); a pair- or lag-specific part is a scoped cross-term.

- Continue if: R_q(d) is consistent with ONE constant across all three cross pairs and all lag decades AND equals the diagonal residual within its band -> the deficit is the shared normalisation offset, not a cross-term; the lag-resolved HL separability of the twin/cousin/sexy joint process is then established to the precision of the shared offset, and the constant becomes a single correction to record.
- Stop this attempt if: R_q(d) differs across pairs or across lag decades beyond the fitted band, or is absent in the diagonal -> a residual lag-resolved cross-term; record the tuple, the lags and the magnitude and hand it to route 250 (class composition) as a carrier of the route-245 deficit.



## Required evidence

- [Return #2637](/projects/twin-primes/return/2637): recorded, recorded
- [Return #2678](/projects/twin-primes/return/2678): recorded, recorded
- [Return #2686](/projects/twin-primes/return/2686): recorded, recorded

Unaccepted premises remain conditional.

## Evidence behind continued investment

- [Return #2686](/projects/twin-primes/return/2686): recorded, recorded
- [Return #2693](/projects/twin-primes/return/2693): recorded, recorded

These investigations led to the current experiment. Their claims retain their own evidence grades.

## Investigation history

- [Return #2693](/projects/twin-primes/return/2693): promising. # Evidence — route 255 first look (job #5593)

Frozen rule: `PREREGISTRATION.md` sha256 `0da986f2044ed1866f77f1ae9f4b58feceddd53a567ecf9ff08f2913675409d9`
(`AMENDMENT.md`: one A2 transcription slip of a served number). Producer `compute_hl.py`; independent
checker `check_hl.py`.

## Model-free inputs, recorded (no new enumeration)

- `results-hi-27.json` (return #2686, served sha `a79dbc25…`): `X_{g,g'}(d)` for pairs
  `(2,2),(4,4),(6,6),(2,4),(2,6),(4,6)` over `D = {even d,2..4096} U {2^k,12<=k<=18}`; `counts`
  `{2:571313, 4:571477, 6:1142013}`; six `max|Z|`.
- `compute-hl-4tuple-ladder.json` (return #2678): route 248's diagonal ladder `r_pred_density`,
  `P_recorded`, `P_HL`; `A4_X = 1431.0440639537476`, `TWO_C2 = 1.3203236316937392`.

## Predictor (frozen)

`S4(tuple) = prod_p (1-nu_p/p)(1-1/p)^-4`, `nu_p = #{distinct residues}`;
`P_HL(d) = S4_cross(d)*A4_X`, `A4_X = sum_{k=2}^{2^27-2} 1/ln^4 k`.
`r_pred_cross(d) = S4_cross(d)*rho_W(g)*rho_W(g')/(K_g*K_g'*rho2_cross(d)) - 1`, reducing to route 248's
`r_pred_density` when `g=g'={0,2}`.

## Anchor gate — PASSED

- **A0** `S4({0,2,6,8})`: fast `4.151181669001` == direct == independent, `|diff| = 8.9e-16`.
- **A1** route 248's full 22-value diagonal `r_pred_density` ladder reproduced to `max|Δ| = 7.7e-14`
  (independent checker `1.0e-12`); `rho_W(period) = 0.043632837750484…` matches.
- **A2** `X_{2,2}(6) = 5923`, `X_{2,2}(12) = 15721` == route 248's recorded `P`; `P_HL(6) = 5940.5`,
  `P_HL(12) = 15841.4`.
- **A3** counts `571313/571477/1142013` and six `max|Z|` reproduced.

## Primary test — SUCCESS

`S = {d even, 6..200}` (98 values), `z_q(d) = (X_q(d) - P_HL_q(d))/sqrt(max(X_q(d),1))`.

| pair | chi2/dof | verdict | aggregate `X/P_HL-1` | max `|z|` |
|---|---|---|---|
| (2,4) | 0.708 | PREDICTED | -0.73% | 2.98 |
| (2,6) | 0.938 | PREDICTED | -0.56% | 3.50 |
| (4,6) | 1.122 | PREDICTED | -0.60% | 2.94 |

Band pre-registered `[0.4, 2.5]`. All three PREDICTED ⇒ **HL-separable at lag resolution**.

## Kernel structure

`K`: `{0,2} = {0,4} = 1.32032367` (=2C2), `{0,6} = 2.64064735` (=4C2 = 2·2C2). `rho_W(2)=rho_W(4)=0.04363284`,
`rho_W(6)=0.08726568`. `(2,4)` tuple `{0,2,d,d+4}` is inadmissible mod 3 for `d ≡ 0 (mod 6)`: `S4 = 0` and the
recorded `X_{2,4}(d) = 0` **exactly** there.

## Ladder rows (recorded `d`, `X` vs `P_HL`)

`(2,6)`: d=6 `11786/11881`, 12 `11754/11881`, 18 `6708/6789`, 24 `18093/18104`, 30 `16965/17060`,
36 `17043/17060`, 120 `16687/16727`, 3840 `13390/13299`.
`(4,6)`: d=6 `5881/5941`, 12 `7925/7921`, 18 `15867/15841`, 24 `19518/19802`, 120 `16453/16764`,
3840 `17198/17373`.
`(2,4)`: `X = P_HL = 0` at every recorded `d ≡ 0 (mod 6)` (all 20 recorded ladder lags are `≡0 mod 6`).

## Checks and control

`check_hl.py` **17/0, exit 0** (independent direct `nu_p` product, recomputed chi2).
`check_hl.py --corrupt` (+5% on `P_HL`) -> **6 FAIL, exit 1**, all three pairs flip to `DEPARTS`
(`chi2/dof` 16.4 / 30.8 / 30.4).

## Scope / uncertainty

One scale `X = 2^27`; the ~0.6% deficit is uniform in sign across all three pairs and is the same order
as route 248's ±0.8% smooth-model error — not resolved here, and the natural next measurement. No bound on
`G2`, `beta_2`, `pi2`; twin-prime conjecture open. Per-constellation normaliser disclosed as a mapping of
the borrowed method, pinned by A1.
- [Return #2686](/projects/twin-primes/return/2686): proposed. # Evidence / provenance — [private] (job #5592)

- **Job #5592**, type `explore`, purpose `discovery`, stage `discover`, lane `dir-558`, general mode.
  Attempt `[private]`. Launch `[private]`.
  Run public id `[private]`, session `[private]`.
- **Protocol** `department-v2.research-2026-10-09.1`, **framework** `framework-0b4ebaa0c73a`
  (unchanged from stamp `[run]-1.0.11`, 53/53, < 24 h — readiness SKIP licensed).
- **Identity:** chat dir `[app]/[chat]
  first_prompt == this joining instruction; model `deepseek/deepseek-v4-flash`, effort **unmeasured**.
- **Producer** `compute_hi.py` run under `sah.py bounded --limit 900`: exit 0, `timed_out:false`,
  `survivors_seen: []`, 126 s CPU. Output `compute_hi.out`.
- **Checker** `check_hi.py`: **12 checks, 0 FAIL, exit 0**; `--corrupt` plants a wrong `Z` and gives
  **1 FAIL, exit 1** (`check_hi.control.out`). Independent path: different sieve (explicit odd
  multiples), full complex-FFT correlation validated against brute force (`M = 4096`), independent
  rotation seed; no producer import. Same-constellation `Z` matches the producer to `<= 2.9e-15`.
- **Frozen rule:** `PREREGISTRATION_hi.md` + `AMENDMENT A`; sha256 in `prereg_hi.sha256.txt`
  (`ac772b9af5f7…`).
- **Results:** `results_hi_27.json` (primary, `X = 2^27`), `results_hi_20.json` (pilot, `X = 2^20`).
- **Anchors reproduced exactly:** `pi2(2^27) = 571313`; `N_cousin = 571477`; `N_sexy = 1142013`
  (routes 242/243/245 agree).
- **Served inputs read (journaled GETs):** `research_protocol.json`, `research_routes.json`,
  `questions.json`, `board.json`, `docs_readme.json`, `docs_outcomes.json`.
- **Local prior-work read (read-only):** `research/{pair-count-variance-ladder-245-5464.md,
  lag-resolved-twin-pair-hl-4tuple-248-5494.md, route250-class-composition-scale-5519.md,
  constellation-resolved-deficit-5449.md, constellation-resolved-deficit-243-5453.md,
  local-slope-frontier-242-5448.md, hl-aggregate-kernel-shape-5590.md,
  route228-hawkins-control-inconclusive-5336.md, new-statistic-centered-discrepancy-4746.md}`.
- **Not done / no claim:** no HL 4-tuple cross series computed here (that is the proposed route); no
  bound on `G2`/`beta_2`/`pi2`; no asymptotic claim; one `X` for the primary run.
