Marathon Fusion gold yield of 0.1+ per fusion neutron confirmed by...?

About this market

On October 21, 2026, Marathon Fusion announced that it had "demonstrated high-rate alchemy," turning mercury into stable gold using fusion neutrons and "beating CERN's record by a factor of 10." (see: https://startupfortune.com/marathon-fusion-says-it-turned-mercury-into-gold-no-proof-yet/) Marathon Fusion's paper titled "Scalable Chrysopoeia via (n, 2n) Reactions Driven by Deuterium-Tritium Fusion Neutrons" (https://arxiv.org/abs/2507.13461) projects gold production of approximately 2 tonnes per gigawatt of thermal fusion power per year, based on neutron transport simulations. This market will resolve to "Yes" if a gold conversion efficiency of at least 0.1 gold atoms per fusion neutron is confirmed through at least one of the qualifying confirmation methods listed below by December 31, 2026, 11:59 PM ET. Otherwise, this market will resolve to "No". A qualifying experiment is one in which stable gold-197 is produced from mercury using neutrons generated by deuterium-tritium fusion reactions (including deuterium-tritium neutron generators), and in which the number of gold-197 atoms produced divided by the total number of fusion neutrons emitted by the neutron source during the irradiation is at least 0.1. The number of gold-197 atoms produced includes gold-197 resulting from the decay of mercury-197 created during the irradiation. The number of fusion neutrons emitted will be the measured total neutron output of the source over the irradiation, not only the neutrons that reach the mercury target. Confirmations that only establish that some gold was produced from mercury, that establish a lower conversion efficiency, that do not report the neutron output of the source, that rely on neutrons not generated by deuterium-tritium fusion reactions, or that are based on simulations or modeling without an experimental demonstration will not qualify. The qualifying confirmation methods are: (i) Peer-reviewed publication: experimental results from a qualifying experiment, whether by Marathon Fusion or by other researchers, are published in a reputable peer-reviewed scientific journal. Preprints and other publications that have not completed peer review will not qualify. (ii) Independent verification: a credible scientific institution unaffiliated with Marathon Fusion (e.g., a national laboratory, university research group, or accredited analytical laboratory) publicly confirms, based on its own measurements of the neutron output and of material irradiated in a Marathon Fusion experiment, or its direct observation of that experiment, that the experiment met the specified conversion efficiency. The confirmation must be published by the verifying institution itself; confirmations relayed only by Marathon Fusion will not qualify. (iii) Independent replication: researchers unaffiliated with Marathon Fusion conduct a qualifying experiment, and the results are made public. Marathon Fusion's employees, investors, and funders, including ARPA-E, Breakthrough Energy, the 1517 Fund, and Strong Atomics, as well as the authors of the paper referenced above, are considered affiliated with Marathon Fusion. Statements, social media posts, or press releases by Marathon Fusion or its affiliates, and media reports that only relay such claims, will not alone qualify. The resolution source for this market will be a consensus of credible sources and relevant scientific experts verifying the legitimacy of the qualifying confirmation. If there is ambiguity as to whether a confirmation under consideration for the resolution of this market is credible, this market may remain open until June 30, 2027, 11:59 PM ET, to allow for the publication of the relevant results in a reputable peer-reviewed journal. One such publication confirming the specified conversion efficiency will be sufficient to resolve this market to "Yes", provided the underlying experiment was conducted by December 31, 2026, 11:59 PM ET. If no such paper is published by this delayed resolution time, this market will resolve to "No".