{"id":"d34d72d0-2f65-41af-b66f-f065ae65a134","arxiv_id":"2505.11292","paper_version":2,"verdict":"UNVERDICTED","confidence":"MODERATE","novelty_score":4.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":3,"one_line_summary":"The ILC collaboration reports a mature SRF-based design, ongoing international R&D through the ILC Technology Network, and an updated ILC250 cost of 6.78 billion ILCU plus 196 billion JPY, while noting Japan has not yet agreed to host.","lead":"This document updates the technical, organizational, and financial status of the proposed International Linear Collider in Japan, including a revised construction cost of 6.78 billion ILCU plus 196 billion JPY for civil work. It is a planning and status report for European Strategy discussions, not a paper presenting new physics results.","discovery_kind":"review","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Cost update's external review is itself unverifiable from the paper's text; the ~30% scaled remainder of the 2017 estimate plus unchanged 2017 human-resource figures makes the 6.78 billion ILCU headline a proponent estimate, not an independently verified price.","rationale":"The reader identified the cost-estimate scaling methodology as the weakest assumption, and the paper's own text confirms that the estimate is not fully bottom-up: more than 70% was re-quoted, but the remaining portion is scaled from 2017, human resources are carried over unchanged, and the backup document is cited for details. The external review committee is named but the review's method, baseline, and acceptance criteria are not described in the paper; this makes the ~30% uncertainty assertion unverifiable from the manuscript alone. The political impediment is also acknowledged in the paper's own summary ('has not yet gained political acceptance'), so the claim that physics can start ten years after project start is conditional on a political path that is not settled. Since the paper is a status document, not a research preprint with a testable scientific claim, marking it UNVERDICTED is the correct disposition rather than rejecting it on technical grounds. The independent evidence that supports the document's credibility is the demonstrated SRF technology (Eu.XFEL, nine-cavity manufacturing started, ATF nano-beam results), which supports technical maturity, but the cost and schedule claims remain proponent estimates. The concrete check that would settle the cost concern is to open the backup document and reproduce the scaling; if the scaling factors are explicit and internally consistent, the estimate becomes verifiable, and if not, the 6.78 billion headline should be treated as a proponent estimate with unquantified systematic error.","tokens_in":10124,"tokens_out":2370,"duration_ms":18657,"concrete_test":"Open the backup document [14] (ILC250 Cost Update - 2024, arXiv:2506.00353) and recompute the headline 6.78 billion ILCU from Table 3 by reproducing the scaling of the unquoted ~30% of the 2017 estimate: check whether the PPP indices, inflation factors, and production-scaling assumptions used for each unquoted line item are stated explicitly, and verify that the 2024 quotations for the >70% re-priced items sum to the reported SRF (3.69), other accelerator (1.71), and CF (1.38) billion ILCU. Independently, recalculate the 7.47 k FTE-years from the 2017 staging report [13] and confirm that no labor productivity or installation learning-curve adjustment was intended; if the human-resource numbers are unchanged, the cost will rise if labor rates have risen since 2017.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim, that the ILC is technically mature and ready for engineering design with an up-to-date cost of 6.78 billion ILCU plus 196 billion JPY, rests on the credibility of the 2024 cost update (§4). The paper's own text (§4.1-4.2) states that only items covering more than 70% of the 2017 estimate were re-priced with 2024 quotations, while the remainder uses scaling factors for inflation, production scaling, and PPP exchange rates. Table 3 carries over 7.47 + 2.65 k FTE-years unchanged from 2017, and the 'reviewed by an international committee' conclusion in §4.2 is asserted without any documented quantitative procedure or uncertainty statement, despite the listed cost-estimate uncertainty of ~30%. The backup document [14] is cited, but the paper itself does not include the scaling factors, the identities of the countries whose PPP indices were applied, or the calculation that leads from the 2017 ILC250 estimate to the 2024 total. Because the new bottom-up quotations cover only the subset of items that were re-priced, the overall estimate remains a hybrid: partly 2024 quotations, partly 2017 estimates scaled by assumptions about inflation and vendor averaging. A ~30% uncertainty on a 6.78 billion headline is not reassuring without evidence on the systematic error of the scaling methodology. The second load-bearing premise is political: §2 and §6 acknowledge that MEXT has not expressed interest and expects international agreement first, while the international community expects Japan to go first.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This paper is a status report from the ILC International Development Team and ILC-Japan, prepared as input to the ESPPU2026 process. It summarizes the IDT organizational structure, the Pre-lab proposal and the MEXT Advisory Panel response, the ILC Technology Network work packages and their implementation status, a 2024 update of the ILC250 cost estimate, construction timescale, environmental and power estimates, and the political situation in Japan. The central technical claims are that the ILC is technically mature and ready for engineering design, that the 2024 cost update gives 6.78 billion ILCU for accelerator and conventional facilities plus 196 billion JPY for civil engineering, and that physics exploitation could begin approximately ten years after project start.","tokens_in":10397,"tokens_out":4439,"duration_ms":40495,"significance":"The strength of the paper is that it provides a compact, clearly referenced summary of the technical program: machine parameters in Table 1, a list of work packages with concrete deliverables, PPP conversion indices in Table 2, and a cost table with a stated breakdown. The use of 2024 vendor quotations for items covering more than 70% of the 2017 estimate, and the explicit separation of civil engineering in JPY, makes the estimate more transparent than the earlier ILC500 figures. If the cost and readiness claims hold, this is an important data point for the European Strategy discussion. However, the paper is a proponent status report; the cost section relies on an externally cited backup document, on scaling factors that are not shown, and on an internal review committee, so the headline number is not independently verifiable from this manuscript alone.","major_comments":[{"comment":"The headline 6.78 billion ILCU is a hybrid estimate: §4.2 states that only items covering more than 70% of the 2017 estimate were re-priced with 2024 quotations, while the remainder is scaled, and Table 3 carries over 7.47+2.65 k FTE-years unchanged from 2017. The manuscript does not give the scaling factors, the countries and PPP indices used, or a sensitivity analysis over the 30% uncertainty. Because the cost figure is the paper's main quantitative claim, the scaling methodology and the sensitivity of the total to the unscaled remainder should be presented in the paper or, if deferred to backup document [14], a quantitative summary should be included here.","section":"§4.2, Table 3"},{"comment":"The statement that \"This result was reviewed by an international committee\" with the conclusion that \"estimated costs and uncertainties are reasonable\" is not accompanied by any description of the review procedure, such as what documents were reviewed, whether the committee performed independent re-estimates, or how the 30% uncertainty band was derived. Since the external review is used as evidence for the reliability of the central number, this is load-bearing; please provide at least the committee's terms of reference and a summary of its findings.","section":"§4.2, footnote 9"},{"comment":"The quoted \"cost of the ILC\" of 6.78 billion ILCU explicitly excludes human resources (7.47 k FTE-years at laboratories and 2.65 k FTE-years for installation), preparatory engineering design, land acquisition, and local infrastructure. This is stated in §4, but the summary and abstract do not repeat the exclusions. Please state the total resource envelope including HR and the excluded items, or clearly headline the figure as \"accelerator and conventional facilities only\" to avoid misinterpretation.","section":"§4.2, Table 3 and §7"},{"comment":"The timescale claim of ten years to physics exploitation assumes a four-year preparatory period, nine-year construction, and one-year commissioning, but no critical-path or risk analysis is provided. Given the acknowledged ~30% cost uncertainty and the unresolved governance sequencing described in §2 and §6, the paper should clarify that this is a technical schedule conditional on political and funding decisions, not a realistic start-date projection.","section":"§5.1"}],"minor_comments":[{"comment":"The sentence \"The new cost estimation for the remaining items was based on the ILC500 cost\" should specify whether the base is the 2017 ILC250 estimate or the ILC500 TDR cost, as the context is ambiguous.","section":"§4.1"},{"comment":"The row \"M&E 1.0 0.91 129.6 1.05 8.83\" is hard to read; please add a note that the first column is USD and clarify why SRF Material is n/a for EUR and CHF.","section":"Table 2"},{"comment":"\"S. Evanse et al.\" appears to be a typo for \"S. Evans et al.\"; please check the author list.","section":"References [15,16]"},{"comment":"The figure is small and the text is dense; in the published version a higher-resolution version would improve readability.","section":"Figure 1"},{"comment":"The phrase \"ILC Technology Network (ITN), in 2023\" reads awkwardly; consider rewording.","section":"§2"}],"recommendation":"major_revision","confidential_remarks":"This is a status and programmatic document rather than a technical paper with new physics results. The cost-estimate transparency is the key issue for a journal referee; the scope is appropriate for a strategy input, but the manuscript should make clear the extent to which the cost number is a proponent estimate. No concerns about citation practices beyond the need to cite the backup cost document explicitly in the main text."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"This is a programmatic status report, not a physics paper, and it should be read that way. The genuinely new content is the 2024 cost update (6.78 billion ILCU for accelerator plus conventional facilities, 196 billion JPY civil engineering), the ITN work-package progress, and the IEP's analysis of why the project is stuck: Japan's MEXT expects an international agreement before a host decision, while partner countries expect Japan to go first. That political section is honestly written and does not paper over the disagreement.\n\nThe cost methodology is presented more transparently than I expected from a collaboration document. The paper says items covering more than 70% of the 2017 estimate were re-priced from 2024 quotations, the rest scaled with stated PPP indices (Table 2), and human resources are carried over from 2017. The breakdown in Table 3 is clear. I also credit the paper for pointing to a backup document with the full basis and for naming the review committee.\n\nThe soft spots are exactly where the stress-test note points. Roughly 30% of the cost is not freshly quoted, the HR numbers are four-year-old carry-overs, the external review's quantitative procedure is not described, and a ~30% uncertainty on a headline of this size needs more supporting evidence than a one-sentence assurance. That said, this is a status report for a strategy process, not a stand-alone cost claim; the backup document exists and should be checked before relying on the number. A minor but real editorial issue is the revision list, where the third revision is dated before the second—sloppy, and it will make careful readers wonder about the document's provenance.\n\nThe assertion that the ILC is 'technically mature and ready for engineering design' is a restatement of the TDR and ATF achievements rather than new evidence. But that is fine for this genre; the paper does not oversell the technical readiness beyond what the TDR already established.\n\nMy bottom line: this is a useful and fairly honest proponent document for the European Strategy discussion. It does not need a standard hep-ex peer review, but it does deserve a serious referee in the strategy context, primarily to interrogate the cost estimate and the political assumptions. I would not cite it in my own work as an independent cost source, but I would bring it to a reading group if the topic is on the table.","headline":"A candid, well-written status report whose real value is the updated 6.78 billion ILCU cost estimate and an unusually frank account of the Japan-MEXT impasse; treat the cost as a proponent estimate pending the backup document.","tokens_in":11766,"tokens_out":1531,"would_cite":false,"duration_ms":17186,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"The paper reports an updated ILC cost of 6.78 billion ILCU plus 196 billion JPY and argues the machine is ready for engineering design.","keywords":["International Linear Collider","Higgs factory","cost estimate","superconducting radiofrequency","positron source","nano-beam","linear collider","European strategy"],"falsifier":"Re-price every item that was carried over by scaling from the 2017 estimate using fresh 2024 vendor quotations and the Japanese tunnel-cost standard; if the resulting total departs from 6.78 billion ILCU by more than the declared 30 percent uncertainty, the updated cost claim would be falsified.","tokens_in":9882,"feed_emoji":"⚛️","tokens_out":7348,"duration_ms":70567,"temperature":0.7,"pith_summary":"The paper makes the case that the International Linear Collider, an electron-positron Higgs factory proposed for Japan, is technically ready to enter engineering design. It reports a 2024 update of the cost estimate: 6.78 billion ILCU for accelerator and conventional facilities plus 196 billion Japanese yen for civil engineering, with about 70 percent of the 2017 estimate re-priced using 2024 quotations. It also reports that the machine could begin physics about ten years after project start, after a four-year preparatory period, nine years of construction, and one year of commissioning. The central political claim is that progress requires an international agreement on building the ILC as a global project before Japan is asked to commit to hosting it.","feed_headline":"ILC cost update: 6.78B ILCU plus 196B JPY for Japan site","feed_subtitle":"Updated 2024 pricing raises the Higgs-factory estimate ~60% and sets a ten-year path to first collisions.","key_machinery":"The cost claim rests on a hybrid estimation method: items covering more than 70 percent of the 2017 ILC250 estimate were re-priced with averaged 2024 quotations from multiple vendors, while the remainder was carried over by scaling the 2017 ILC500 bottom-up estimate for inflation, production scaling, and exchange-rate shifts. Purchasing-power-parity indices convert non-dollar costs into ILCU, and civil engineering follows Japanese government tunnel-costing standards and is kept in yen. The technical-readiness argument rests on superconducting radiofrequency technology already used in operating accelerators and on nano-beam focusing demonstrations that reached 41 nm against a 37 nm target, with remaining risks assigned to the work packages of the ILC Technology Network.","core_discovery":"The updated cost estimate is the paper's central result. It puts the ILC at a center-of-mass energy of 250 GeV, with accelerator and conventional facilities costing 3.69 billion ILCU for superconducting radiofrequency components, 1.71 billion ILCU for other accelerator items, and 1.38 billion ILCU for conventional facilities, plus 196 billion JPY for civil engineering in Japan. Human resources are unchanged from 2017: 7.47 thousand FTE-years at laboratories and 2.65 thousand FTE-years for installation. Compared with 2017, the accelerator and conventional-facilities cost rises by about 60 percent, roughly 35 percentage points of which the paper attributes to worldwide inflation, and civil engineering rises by about 50 percent. The paper states the cost uncertainty is about 30 percent and that an international review committee found the estimates and uncertainties reasonable.","pith_inferences":["If the stated 30 percent uncertainty is taken literally, the headline accelerator and conventional-facilities cost could range roughly from 4.7 to 8.8 billion ILCU before adding civil engineering; readers comparing projects should ask whether other estimates quote the same scope and uncertainty convention.","The unchanged human-resource figures are the least-tested part of the estimate; a useful check would be to compare the staffing implied by the detailed work-package plans with the commitments laboratories have actually made.","If the ILC Technology Network work packages finish on their announced two-to-four-year schedule, the remaining engineering risks such as cavity production at scale, nano-beam stability, and positron-target replacement will be retired before engineering design begins, making the ten-year physics timeline testable.","A direct numerical comparison with other proposed Higgs factories requires converting both cost bases to a common currency and scope convention, since the ILC number excludes land, local infrastructure, experiments, and preparatory engineering design."],"forward_implications":["If the cost estimate holds, strategy discussions now have a concrete 2024 baseline price for an ILC-based Higgs factory: 6.78 billion ILCU plus 196 billion JPY, which supersedes the older 2017 numbers in any comparison.","If technical maturity is accepted, the project can move into a four-year preparatory engineering-design phase, followed by nine years of construction and one year of commissioning, putting first physics ten years after project start.","The updated estimate includes explicit upgrade paths: raising the energy to 500 GeV would add 3.9 to 4.2 billion ILCU plus 55 billion JPY, and an electron-driven positron source as a backup would add 0.20 billion ILCU plus 12.5 billion JPY.","The phased governance proposal, an international agreement first and host selection second, offers a route around the impasse in which the Japanese government waits for an international consensus while partner governments wait for a Japanese expression of interest."],"supporting_citations":[{"why":"It supplies the 2013 Technical Design Report that defines the machine design and the original ILC500 bottom-up cost basis.","marker":"[4–8]"},{"why":"It is the 2017 ILC250 staging report whose cost estimate is the baseline being updated, with more than 70 percent of its items re-priced in 2024.","marker":"[13]"},{"why":"It contains the comprehensive backup details of the 2024 cost update, including the quotation and scaling data behind the headline figure.","marker":"[14]"},{"why":"It defines the proposed Preparatory Laboratory and its work packages, which supports the claim that the next phase is engineering design.","marker":"[10]"},{"why":"It establishes the ILC Technology Network and its work packages, which carries the technical-readiness and risk-retirement argument.","marker":"[12]"},{"why":"It records the advisory panel conclusion that a pre-laboratory would be premature, motivating the paper's phased international-agreement approach.","marker":"[11]"}],"fun_headline_variants":["ILC cost rises 60% to 6.78B ILCU plus 196B JPY for Japan","New ILC estimate: 6.78B ILCU, 196B JPY, 60% above 2017","ILC price tag updated: 6.78B ILCU, 196B JPY site work","ILC update: 6.78B ILCU machine, 196B JPY civil, 30% uncertainty","ILC costs jump 60%: 6.78B ILCU and 196B JPY for Japan"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The headline cost assumes that the scaling factors applied to the un-repriced remainder of the 2017 estimate and the unchanged 2017 human-resource figures are still accurate.","fun_headline_variants_meta":{"raw":{"variants":["ILC cost rises 60% to 6.78B ILCU plus 196B JPY for Japan","New ILC estimate: 6.78B ILCU, 196B JPY, 60% above 2017","ILC price tag updated: 6.78B ILCU, 196B JPY site work","ILC update: 6.78B ILCU machine, 196B JPY civil, 30% uncertainty","ILC costs jump 60%: 6.78B ILCU and 196B JPY for Japan"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000494,"raw_usage":{"total_tokens":2361,"prompt_tokens":817,"completion_tokens":1544,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":433,"completion_tokens_details":{"reasoning_tokens":1401}},"tokens_in":433,"tokens_out":1544,"duration_ms":11292,"temperature":1.0,"reasoning_tokens":1401,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-15T20:54:26.270013+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Re-price every item that was carried over by scaling from the 2017 estimate using fresh 2024 vendor quotations and the Japanese tunnel-cost standard; if the resulting total departs from 6.78 billion ILCU by more than the declared 30 percent uncertainty, the updated cost claim would be falsified.","supporting_citations":[{"cited_title":"ILC Technology Network (ITN) and work packages,","cited_arxiv_id":null,"evidence_quote":"It establishes the ILC Technology Network and its work packages, which carries the technical-readiness and risk-retirement argument."},{"cited_title":"Summary of Discussions on Issues Relating to the International Linear Collider (ILC) Project","cited_arxiv_id":null,"evidence_quote":"It records the advisory panel conclusion that a pre-laboratory would be premature, motivating the paper's phased international-agreement approach."}],"review_version":1}