{"id":"4d89b5e1-33a7-42c9-a25e-0e7142e4da95","arxiv_id":"1908.04139","paper_version":3,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":0,"one_line_summary":"CREDO proposes a global network of smartphones and established detectors to search for cosmic-ray ensembles, and reports a first null-result test of its time-correlation tool.","lead":"This paper describes CREDO, a project that turns smartphones and existing detectors into one worldwide cosmic-ray observatory. It reports the project's early status: thousands of users, a working app, and a first search for correlated events that found nothing yet.","discovery_kind":"new_method","skeptic_critique":{"model":"deepseek-v4-flash","headline":"CREDO's central science case assumes uncalibrated smartphone detectors can support a global correlation search; without measured efficiency and timestamp accuracy, no sensitivity estimate is possible.","rationale":"Good faith reading: the paper is a status report, not a discovery claim. It provides user statistics, open-source code, and a preliminary null result; those support the claim that the network exists and operates. My concern is not that the project is fraudulent or impossible; it is that the decisive scientific premise, smartphone sensitivity to CRE, is unmeasured. I agree with the reader's weakest assumption; both identify Sec. 2's unquantified smartphone detection capability as the soft spot. I also note that Sec. 4's radiation-dose sentence (40 mGy or larger applied to a significant fraction of the population at least once during a lifetime) appears to overstate the likelihood of human exposure to 10^18 eV air-shower cores and should be revised, but it is peripheral to the main argument. Since the reader's verdict was already CONDITIONAL and my analysis does not change that, the verdict remains unchanged.","tokens_in":5683,"tokens_out":3517,"duration_ms":41377,"concrete_test":"Calibrate the CREDO Detector app on representative phones against a GPS-disciplined scintillator telescope: measure (i) muon detection efficiency (tracks per incident muon), (ii) rate of false-positive tracks from electronics or light leakage, and (iii) timestamp error (offset and jitter relative to a 1 PPS signal, including clock drift between charges). Then inject simulated CRE events into real user timestamps with those errors and rerun the QGP doublet search to determine the minimum detectable CRE rate. If no CRE-like signal is recovered unless timing precision is sub-second across devices, the global-smartphone component alone cannot support the stated science case.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The most load-bearing assumption is that the smartphone segment of CREDO can contribute to a physically meaningful global correlation search. In Sec. 2 the paper states that 'a smartphone with the CREDO Detector is capable of detecting particle track candidates,' but it provides no measured detection efficiency, no dark-rate characterization, and no timestamp accuracy or clock-synchronization analysis for the app. A search for cosmic-ray ensembles is a counting experiment: the expected accidental-coincidence rate under the null hypothesis must be computed from per-device rates and timing uncertainties, and the sensitivity to a true CRE depends on those numbers. The QGP doublet analysis shown in Fig. 4 is a useful consistency test for one user, but scrambled timestamps can only validate the analysis pipeline against a flat-time null; they cannot establish that a CRE signal would survive the same pipeline. The paper's own Sec. 2 acknowledges that 'even the most peculiar anomaly observed with one technique only, e.g. by smartphone sensors, cannot be considered a real physical phenomenon unless it is observed independently, with detectors of other types.' That limitation is appropriate for a status report, but it means the central science claim, that the network can search for and potentially detect CRE, is not yet supported by measurement; it is a plausible proposal awaiting calibration.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This ICRC2019 proceedings paper presents the status and perspectives of CREDO, a proposed worldwide network that combines existing cosmic-ray detectors—including professional arrays, educational instruments, and smartphone cameras—to search for cosmic-ray ensembles (CRE), a hypothesized class of extended, globally correlated cosmic-ray phenomena. The paper describes the project's concept, the CREDO Detector smartphone app, the open-source and open-data infrastructure, the current user base (7500 users, ~2.9 million images), a first proof-of-principle analysis of time-correlated doublets for a single user using scrambled-map backgrounds, and planned citizen-science and interdisciplinary activities. The central claim is that the distributed smartphone cloud, complemented by scintillator detectors and existing observatories, can enable global searches for CRE that are beyond the reach of individual observatories.","tokens_in":5876,"tokens_out":2899,"duration_ms":34048,"significance":"If the framework performs as proposed, CREDO would open a genuinely new observational window: no existing facility can search for cosmic-ray phenomena spread over a significant fraction of the Earth. The paper's strengths are its open-source code and open-data model, the already operational citizen-science infrastructure with thousands of contributing users, and the use of a scrambled-map background in the illustrative doublet analysis, which provides a template for blind analyses. The scientific significance, however, currently rests on an unvalidated assumption—that smartphone CMOS sensors can provide event rates and timing precision sufficient for meaningful global correlation searches. The paper explicitly acknowledges that smartphone-only observations would need confirmation with other detector types, but it does not provide the calibration or sensitivity estimates needed to assess whether the smartphone component can contribute at all. As a status report the paper is informative, but as a scientific feasibility claim it is not yet supported.","major_comments":[{"comment":"The sentence 'a smartphone with the CREDO Detector is capable of detecting particle track candidates' is presented without any supporting calibration: no detection efficiency, no dark-rate or false-track rate, no timestamp resolution, and no clock-synchronization analysis are given. Since the paper later states that the smartphone cloud is 'the first step' and a 'critically important' component of CREDO, this uncalibrated claim is load-bearing: the accidental-coincidence rate and the sensitivity of any global CRE search are direct functions of per-device trigger rates and timing uncertainties. The authors should either provide measured values (or cite a peer-reviewed characterization) or explicitly reframe the statement as 'the app recognizes track-like patterns whose physical origin remains to be validated.'","section":"Sec. 2 (smartphone detection capability)"},{"comment":"The scrambled-map background is generated from 'randomly generated timestamps using a flat distribution,' but the significance calculation is only referenced to [11] and no systematic uncertainties are presented. Real smartphone data are subject to diurnal user-activity modulation, variable network latency, detector dead time, and timestamp quantization, all of which can alter the expected doublet rate. As shown, the compatibility statement for the single user is qualitative; the authors should define the significance parameter explicitly, discuss the validity of a flat-time null for this dataset, and quantify at least the dominant systematic uncertainties or label the figure as an illustrative pipeline demonstration.","section":"Sec. 2, Fig. 4 (doublet analysis)"},{"comment":"The claim that 'the observing time for all users equates to 958 years searching for particles' is not derived. It is unclear whether this is total wall-clock integration time, active-exposure time after dark-frame rejection, or a scaled quantity based on pixel counts. Without the underlying formula and an assumption about the per-image detection rate, this number is misleading to readers and could be misinterpreted as the equivalent live time of a physics detector. A short derivation or a reference to a technical note is needed.","section":"Sec. 2 (observing-time claim)"},{"comment":"The manuscript does not address how timestamps from geographically distributed smartphones are synchronized. A global search for CRE requires correlating events at different locations with time differences that could be as short as milliseconds or as long as minutes; the relevant tolerance depends on the scenario. The paper mentions temporal dispersion 'of the order of minutes or more' for some reported phenomena, but does not discuss whether smartphone clock errors (typically seconds to tens of seconds without disciplined synchronization) are tolerable or how synchronization would be achieved. This is an essential technical requirement for the central science goal and should be addressed in a status report.","section":"Sec. 2 (network timing)"}],"minor_comments":[{"comment":"Reference [4] cites 'Physics Review D'; the journal name should be 'Physical Review D'.","section":"References"},{"comment":"Reference [24] is a conference talk; if a published counterpart exists, it should be cited instead, particularly because the dose-risk statement in Sec. 4 relies on it.","section":"Reference [24]"},{"comment":"The world map of user locations would benefit from a color scale or count legend so that the density of users is quantitatively interpretable.","section":"Fig. 3"},{"comment":"The acronym CRE is defined in the abstract but the definition is repeated in the introduction; consider using the definition only at first occurrence.","section":"Sec. 2, first paragraph"},{"comment":"The statement about an adult human receiving a dose of 40 mGy or larger 'at least once during an individual lifetime' from [24] is nontrivial and should be accompanied by the underlying flux calculation or a proper peer-reviewed reference, rather than a conference talk.","section":"Sec. 4"}],"recommendation":"major_revision","confidential_remarks":"This is a conference proceedings paper, and the editorial bar is lower than for a full research article. Nonetheless, the central scientific claim—that a global smartphone-based network can search for cosmic-ray ensembles—is presented without the basic detector characterization needed to assess its feasibility. The authors' own Sec. 2-acknowledged limitation (that a phone-only anomaly requires confirmation with other detector types) is consistent with this concern. The paper would be publishable after adding calibration data or clearly reframing the smartphone capability as unvalidated, and after addressing the systematics issue in Fig. 4. I would support acceptance after a major revision that addresses the load-bearing calibration and timing issues."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Short version: this is an honest status report for a citizen-science cosmic-ray network. The genuinely new thing is the distributed, smartphone-inclusive detection concept and the first null sanity check; there is no physics discovery, and the smartphone sensitivity question is not answered. That said, it deserves a serious referee as an instrument/status paper.\n\nWhat it does well: it describes an observational strategy that is actually different — correlating globally separated detectors to look for cosmic-ray ensembles rather than single air showers. The project has shipped more than most proposals: an open-source app, an open API, a github repository, and real operational numbers (7500 users, 2.9 million images, 958 years of observing time as of July 2019). The QGP doublet analysis shown for one user uses scrambled timestamps as a background estimate and finds consistency with background, which is the appropriate sanity check for a framework paper. The authors also state plainly that a phone-only anomaly would need independent confirmation with other detector types. That is honest.\n\nSoft spots: the central science case assumes smartphone CMOS sensors can contribute to a meaningful global correlation search, but the paper gives no measured detection efficiency, no dark-rate characterization, no timestamp accuracy, and no clock-synchronization analysis. For a counting experiment looking for accidental coincidences, those numbers are load-bearing. Without them, the sensitivity to cosmic-ray ensembles is unknown. This does not kill the paper, because it is a status report, but it means the main physics promise is an unproven proposal. The doublet analysis itself is a pipeline test against a flat-time null; it would not necessarily catch a real ensemble signal, which could have its own time structure. That limitation should be stated. Section 4 is the weakest part: earthquake prediction and the 40 mGy dose claim are speculative and not supported by the data in this paper. They read as wish-list and are unnecessary for the project description.\n\nThe citation pattern is fine. Earlier CREDO papers and the relevant literature are cited, and the preshower simulations serve as motivation rather than as a load-bearing derivation.\n\nThe paper is for astroparticle and instrumentation readers interested in citizen-science detectors, and for referees tracking project milestones. I would accept it for peer review as a status paper, with the expectation that Section 4 is trimmed or clearly labeled speculative and the smartphone-calibration gap is acknowledged as required future work. A serious referee can get useful signal from this manuscript.","headline":"Honest status report for a global citizen-science cosmic-ray network; no physics result yet, but the infrastructure and null check earn a serious referee.","tokens_in":6522,"tokens_out":2351,"would_cite":false,"duration_ms":25222,"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":"This paper argues that cosmic-ray ensembles—many particles arriving nearly simultaneously across huge distances—could be searched for by combining the world's existing cosmic-ray detectors, including smartphones, into one global network.","keywords":["cosmic-ray ensembles","global detector network","smartphone detectors","citizen science","preshower cascades","ultra-high-energy cosmic rays","distributed observatory"],"falsifier":"Measure the per-phone track-detection efficiency and timestamp precision of the CREDO Detector app against a scintillator coincidence telescope in the field; if the phone timing error exceeds the few-millisecond light-travel delay expected across a 1000 km-scale ensemble, or if detection efficiency is too low to register particles at the expected density, the claimed global network cannot distinguish a real ensemble from background. Alternatively, a global search using the paper's scrambled-map method that finds no significant excess of correlated doublets at the spatial and temporal scales predicted by preshower models would falsify the near-term discovery claimed for the framework.","tokens_in":5495,"feed_emoji":"🌍","tokens_out":6867,"duration_ms":72685,"temperature":0.7,"pith_summary":"This paper argues that a class of cosmic-ray phenomena—cosmic-ray ensembles, many particles arriving nearly simultaneously across separations of hundreds of kilometres—has been missed because every existing observatory looks for single air showers. It proposes a single worldwide network, CREDO, that combines professional arrays, educational instruments, and ordinary smartphones into one global detector. The paper reports that the phone component already spans the planet, with thousands of users and millions of images, and that a first search for pairs of detections in five-minute windows is consistent with background. The stakes are high: if ensembles are found they could probe energies near the grand-unification scale, and if they are absent the null result would constrain current and future theories.","feed_headline":"Smartphone network aims to spot cosmic-ray ensembles spanning Earth","feed_subtitle":"A global array of existing detectors could catch correlated cosmic rays no single observatory can see.","key_machinery":"The paper's central object is the cosmic-ray ensemble (CRE): a group of air showers and individual particles that arrive at Earth as one correlated event, possibly spanning many hundred kilometres. The mechanism that carries the argument is a two-layer detection chain: a cloud of consumer CMOS cameras (smartphones running the CREDO Detector app, in combination with educational and professional instruments) supplies the geographic spread, while an open server-side analysis pipeline, including the Quantum Gravity Previewer, searches for clusters of time-correlated detections and compares their rate with scrambled-map background simulations. Preshower cascades initiated by ultra-high-energy photons interacting near the Sun or in the terrestrial magnetic field, and decays of super-massive particles, supply concrete production scenarios that give the ensemble search defined expectations to confirm or exclude.","core_discovery":"The central claim is that cosmic-ray ensembles are a real, unexamined target and that the way to observe them is not a larger single detector but a planetary array assembled from already-operating instruments. A candidate signal spread over a significant fraction of Earth's surface would leave too few particles at any one site for a single observatory to recognize, but a coordinated global network could register two or more correlated particles or photons and recognize the pattern. The paper establishes the concept's feasibility: smartphone sensors can record particle-track candidates, the open-source app and open data API already collect data globally, and the analysis framework, including the Quantum Gravity Previewer and scrambled-map background estimates, can search for time-correlated clusters. It does not claim an ensemble detection; it claims the observational strategy is operational and that the absence of any confirmed multi-technique observation is what the network is designed to remedy.","pith_inferences":["If smartphone timestamps are only good to seconds rather than milliseconds, the phone cloud alone cannot identify a true simultaneous ensemble; a practical extension would be to require an external time-synchronization protocol or to restrict phones to veto or trigger roles.","The same distributed-coincidence architecture could be applied to other global correlated phenomena, such as searching for transient optical or radio counterparts of astrophysical events, by treating any sensor with a timestamp as a node.","A testable near-term check would be to correlate CREDO phone track rates with the known muon flux as a function of latitude and altitude; if the phone response does not track the expected flux, per-device detection efficiency is too variable for quantitative ensemble searches.","The five-minute doublet analysis shown in the paper is far coarser than the millisecond-scale simultaneity expected from a light-speed front; tightening the coincidence window is a direct way to raise sensitivity if sensor timing allows."],"forward_implications":["If ensembles are real, CREDO's global network is the only class of instrument that can see them, because the signal's footprint exceeds any single existing observatory.","A null result from a full global search would place new constraints on preshower and top-down models, including limits on ultra-high-energy photon fractions and on decays of super-massive particles.","Any candidate detection from smartphone sensors would not be accepted on its own; the paper commits to independent confirmation with scintillator-based detectors and other techniques, so the framework grows a multi-technique core.","The citizen-science model turns data acquisition into a scalable resource: more phones means more geographic coverage and more manpower for analysis, not just better statistics."],"supporting_citations":[{"why":"Computes preshower cascades from ultra-high-energy photons interacting close to the Sun, providing the main production scenario for cosmic-ray ensembles.","marker":"[1]"},{"why":"Derives the expected spatial distribution of a preshower at Earth and argues CREDO would be sensitive to it.","marker":"[2]"},{"why":"Presents top-down decay of super-massive particles as a source of ultra-high-energy photons, a second CRE scenario.","marker":"[4]"},{"why":"Reports groups of time-correlated cosmic-ray photons with minute-scale dispersion, the historical observations that CREDO would confirm or exclude.","marker":"[5]"},{"why":"Provides a second independent report of time-correlated gamma-ray groups, strengthening the motivation for a dedicated search.","marker":"[6]"},{"why":"Is the CREDO Detector smartphone app through which citizen scientists acquire particle-track data.","marker":"[7]"},{"why":"The Quantum Gravity Previewer searches for clusters of time-correlated events in the smartphone data stream.","marker":"[10]"},{"why":"Defines the significance calculation for doublets based on scrambled-map background simulations, the method behind the first CREDO analysis.","marker":"[11]"}],"fun_headline_variants":["Global detector mesh targets cosmic-ray showers that span continents","No single observatory can catch these cosmic rays; a worldwide network can","Citizen science network hunts for Earth-sized cosmic-ray patterns","Cosmic-ray ensembles: the untapped signal a planet-wide array could catch","Turning every detector on Earth into one telescope for cosmic-ray ensembles"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing premise is that the camera sensors in ordinary smartphones can detect individual cosmic-ray particles and time them accurately enough that a worldwide phone network can tell a true cosmic-ray ensemble from random background.","fun_headline_variants_meta":{"raw":{"variants":["Global detector mesh targets cosmic-ray showers that span continents","No single observatory can catch these cosmic rays; a worldwide network can","Citizen science network hunts for Earth-sized cosmic-ray patterns","Cosmic-ray ensembles: the untapped signal a planet-wide array could catch","Turning every detector on Earth into one telescope for cosmic-ray ensembles"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000897,"raw_usage":{"total_tokens":3829,"prompt_tokens":874,"completion_tokens":2955,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":490,"completion_tokens_details":{"reasoning_tokens":2866}},"tokens_in":490,"tokens_out":2955,"duration_ms":21228,"temperature":1.0,"reasoning_tokens":2866,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-14T13:49:43.192379+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Measure the per-phone track-detection efficiency and timestamp precision of the CREDO Detector app against a scintillator coincidence telescope in the field; if the phone timing error exceeds the few-millisecond light-travel delay expected across a 1000 km-scale ensemble, or if detection efficiency is too low to register particles at the expected density, the claimed global network cannot distinguish a real ensemble from background. Alternatively, a global search using the paper's scrambled-map method that finds no significant excess of correlated doublets at the spatial and temporal scales predicted by preshower models would falsify the near-term discovery claimed for the framework.","supporting_citations":[{"cited_title":"Homola et al., Comput","cited_arxiv_id":null,"evidence_quote":"Computes preshower cascades from ultra-high-energy photons interacting close to the Sun, providing the main production scenario for cosmic-ray ensembles."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Presents top-down decay of super-massive particles as a source of ultra-high-energy photons, a second CRE scenario."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Reports groups of time-correlated cosmic-ray photons with minute-scale dispersion, the historical observations that CREDO would confirm or exclude."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Provides a second independent report of time-correlated gamma-ray groups, strengthening the motivation for a dedicated search."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Is the CREDO Detector smartphone app through which citizen scientists acquire particle-track data."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"The Quantum Gravity Previewer searches for clusters of time-correlated events in the smartphone data stream."},{"cited_title":"Góra et al., Universe, 4(11) (2018) 111","cited_arxiv_id":null,"evidence_quote":"Defines the significance calculation for doublets based on scrambled-map background simulations, the method behind the first CREDO analysis."}],"review_version":1}