{"id":"77ee49ee-ed01-4df7-91a2-557778b317bc","arxiv_id":"2504.17174","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":4.0,"correctness_risk":"low","formal_verification":"none","parameter_count":0,"one_line_summary":"The 856.2-keV and 1405.0-keV transitions are placed in the 114Sn level scheme, connecting the 0+3 state at 2156.0 keV to the 2+1 state and to a state at 3561.0 keV in the beta-decay channel.","lead":"This experiment maps gamma-ray decays in the tin isotope 114Sn using the GRIFFIN spectrometer. It places two previously unplaced transitions into the level scheme, a small step toward understanding shape coexistence in tin nuclei.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Gate purity for the 856.2-keV coincidence is not demonstrated; the 1405.0-keV placement rests on an uncharacterized cocktail-beam gate.","rationale":"I read the paper as a preliminary spectroscopy report whose central claim is narrow: two gamma-ray transitions are assigned to the 114Sn level scheme, with the 1405.0-keV transition placed above the 0+3 level at 2156.0 keV. The evidence is a coincidence spectrum gated on 856.2 keV showing 1299.8 and 1405.0 keV. The energy sums are internally consistent: 856.2 + 1299.8 = 2156.0 and 1405.0 + 2156.0 = 3561.0, and prior literature places these transitions in 114Sn, giving plausibility. The load-bearing concern is the uncharacterized purity of the 856.2-keV gate. The cocktail beam and the absence of random subtraction, beam-off gating, or a reverse gate leave open the possibility that the 1405.0-keV coincidence is contaminated. This is precisely the reader's weakest assumption, so I agree with the conditional verdict. I would not move to reject because the claim is modest, the energy sums are consistent, and the proposed check can be done with existing data. The verdict stays conditional pending that check.","tokens_in":5128,"tokens_out":5161,"duration_ms":50370,"concrete_test":"Re-analyze the list-mode data with a symmetric coincidence check: (1) build a gamma-gamma matrix with a time-random background window and subtract random coincidences; (2) gate on 1299.8 keV and fit the 856.2-keV and 1405.0-keV peaks; (3) set off-peak gates at 856.2 +/- 3 keV and a beam-off 856.2 gate, and compare the 1405.0-keV intensity. If the 1405.0-keV peak survives the reverse 1299.8-keV gate, is absent in off-peak/beam-off gates, and remains after random subtraction, the placement is confirmed. If not, the placement should be reported as tentative pending a peak-purity analysis.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim is the placement of the 856.2-keV and 1405.0-keV transitions in the 114Sn level scheme, with Fig. 4 as the key evidence: the 856.2-keV gate shows coincident 1299.8-keV and 1405.0-keV lines. The weakest link is that the 856.2-keV gate is assumed to be a single, uncontaminated 114Sn transition. The beam is explicitly described as a cocktail containing 114Sb, 114In isomers, and 95Sr19F (Section 2), and the singles spectra show strong non-114Sn lines. No random-coincidence subtraction, no beam-off gated spectrum, no peak-shape fit of the 856.2-keV gate, and no reverse gate on 1299.8 keV are shown. Because 856.2 + 1299.8 = 2156.0 is a known level, even a contaminated 856.2-keV peak would display 1299.8 if the contaminant belongs to a related cascade, and the 1405.0-keV line could come from a different sequence. The paper cites prior (n,n'gamma) work [13] that placed these transitions, which supports plausibility, but the claimed beta-decay placement should be supported by the present data, and the data shown are not sufficient to exclude contamination. This is a missing-evidence concern, not a demonstrated error, and it is testable with the existing GRIFFIN dataset.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper reports a preliminary gamma-ray spectroscopy study of 114Sn populated by the beta-plus/electron-capture decay of 114Sb produced at TRIUMF-ISAC and detected with the GRIFFIN spectrometer. The authors identify two previously unplaced transitions, 856.2 keV and 1405.0 keV, and place them in the 114Sn level scheme: 856.2 keV depopulates the proposed 0+3 level at 2156.0 keV to the 2+1 level at 1299.8 keV, and 1405.0 keV is placed between a level at 3561.0 keV and the 2156.0-keV level. The placement rests on a gamma-gamma coincidence spectrum gated on 856.2 keV that shows coincident 1299.8-keV and 1405.0-keV peaks. The paper also describes the cocktail-beam composition and singles spectra used to characterize the beam, and it outlines future work on intensities, log ft values, and angular correlations.","tokens_in":5426,"tokens_out":4472,"duration_ms":38355,"significance":"If the assignments are correct, the result removes a minor discrepancy between an older beta-decay study and a later (n,n'γ) study, and it provides a starting point for studying decay patterns of excited 0+ states in 114Sn. The paper's value is incremental rather than transformative: it is a short, preliminary report whose central evidence is a single coincidence gate. The experiment itself benefits from high statistics and the well-characterized GRIFFIN array, and the placement is physically plausible given Ref. [13] and the Ritz combination 856.2+1299.8=2156.0. No code or machine-checked proofs are involved; the key requirement is that the coincidence data be shown to be robust against contamination and background.","major_comments":[{"comment":"The 856.2-keV gate is not demonstrated to be pure. Section 2 states that the beam contains 114Sb, 114In isomers, and 95Sr19F, so the gate may include contributions from these species, and no peak-shape fit, peak-purity analysis, background subtraction, or chance-coincidence correction is shown. Because 856.2 + 1299.8 = 2156.0 keV is a known level energy, a contaminated gate could still display the 1299.8-keV line through a related cascade, and the 1405.0-keV line could arise from a different sequence. Without these controls, the coincidence spectrum in Fig. 4 does not uniquely determine the placement; a reverse gate on 1405.0 keV or a detailed analysis of the 1299.8-keV gate is needed.","section":"Section 3, Fig. 4"},{"comment":"No uncertainties are given for the energies or intensities of the transitions used in the placement, and no quantitative measure of peak significance (e.g., peak area, background level, or number of counts) is provided. The central claim is a two-point energy sum plus a coincidence observation; at minimum the energies should be quoted with uncertainties from a calibration fit, and the 1405.0-keV peak should be shown to be statistically significant above the local background.","section":"Section 3, Fig. 4"},{"comment":"The paper does not present a coincidence spectrum gated on the 1405.0-keV transition or a spectrum gated on the 1299.8-keV transition showing the 856.2-keV and 1405.0-keV lines. The single forward gate shown in Fig. 4 is the only evidence for mutual coincidence; a mutual-coincidence check is standard and would directly address the cocktail-beam contamination concern.","section":"Section 3"}],"minor_comments":[{"comment":"The notation 'β+−decay' in Section 3 is a typo and should be typeset consistently as 'β+ decay'.","section":"Abstract and Section 3"},{"comment":"The caption mentions a 'yellow star' marker, but the marker is not clearly visible in the printed figure; please adjust the figure or caption for clarity.","section":"Fig. 2"},{"comment":"The inset showing the 856.2-keV gate is too small to read the gate limits clearly; the energy scale and gate boundaries should be enlarged and labelled.","section":"Fig. 4"},{"comment":"The isomeric-state labels '114Inm1' and '114Inm2' should use a consistent superscript notation (e.g., 114Inm1) throughout the text and references.","section":"Section 2"}],"recommendation":"major_revision","confidential_remarks":"The manuscript is very short and self-described as preliminary. The missing controls are all obtainable from the existing dataset, so major revision is appropriate rather than rejection. The editor may also wish to consider whether the journal's standard for a 'preliminary results' letter is met; if not, the authors might be encouraged to extend the analysis to include intensities and at least one confirmatory gate before acceptance."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"The paper does what it says: it places the 856.2-keV and 1405.0-keV transitions in the 114Sn level scheme using beta-decay data from GRIFFIN, confirming a placement that Araddad et al. already made in 1990 via (n,n'gamma). The genuinely new part is the confirmation in the beta-decay channel with high statistics. That is a modest but legitimate contribution.\n\nThe GRIFFIN data look solid in the sense that the coincidence gate on 856.2 keV shows the expected 1299.8-keV line and the new 1405.0-keV line, and the paper is transparent about the cocktail beam and the fact that this is preliminary. I appreciate that they cite the 1990 work rather than pretending the placement is new, though the abstract's phrasing \"have been assigned to the level scheme\" is a bit strong given the prior assignment.\n\nSoft spots: the gate purity issue is real but not fatal. They show no background subtraction, no random-coincidence estimate, and no reverse gate on 1299.8 keV. Since 856.2 is a known transition from the 0+3 state, and the beam contains other contaminants, the 1405.0-keV coincidence should be backed by a cleaner gate. That said, the placement does not rest on this paper alone; it was already established elsewhere. So the missing analysis is a completeness issue, not a demonstrated error.\n\nMinor: the paper talks about expanding the level scheme beyond 4 MeV, but the results here are just two transitions; the real expansion is promised for the future article. Also, no uncertainties are quoted on the transition energies shown in Figure 4, though the prior values are presumably consistent.\n\nOverall, this is a short preliminary report from a large collaboration. It is not groundbreaking, but it is honest and the physics is fine. If it is meant as a proceedings note, it is acceptable as is. If it is submitted as a regular letter, I would want the gate-purity analysis added. Either way, it deserves peer review, not a desk rejection.","headline":"A small, honest confirmation paper: two transitions are placed in 114Sn from beta decay, but they were already placed in a 1990 (n,n'gamma) experiment; the new data support the placement but lack gate-purity analysis.","tokens_in":6221,"tokens_out":2207,"would_cite":false,"duration_ms":21395,"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":"Gating on a 856.2-keV gamma ray places two previously unassigned transitions in the level scheme of 114Sn, linking the deformed 0+3 state to its feeding and ground-state transitions.","keywords":["gamma-ray spectroscopy","shape coexistence","GRIFFIN","Sn nuclei","114Sn","excited 0+ states","beta decay","level scheme"],"falsifier":"Look at the 856.2-keV peak for doublet structure or background contamination and test the reverse gates: gating on 1405.0 keV should reproduce the 1299.8-keV and 856.2-keV lines, and gating on 1299.8 keV should show both. If the 1405.0-keV gate does not show 856.2 keV and 1299.8 keV with consistent relative intensities, the claimed cascade fails.","tokens_in":4957,"feed_emoji":"⚛️","tokens_out":7814,"duration_ms":64278,"temperature":0.7,"pith_summary":"The paper reports a gamma-ray coincidence measurement that places two previously unassigned transitions in the beta-decay level scheme of 114Sn. Using the GRIFFIN spectrometer, the authors gate on a 856.2-keV gamma ray and observe it in coincidence with the known 1299.8-keV ground-state transition and a 1405.0-keV transition. This assigns 856.2 keV as the decay of the 0+3 level at 2156.0 keV to the 2+1 level, and 1405.0 keV as the transition feeding that level from a state at 3561.0 keV. The placement matters because it anchors the decay of an excited deformed state in a semi-magic nucleus, providing a firmer experimental footing for shape-coexistence studies across the tin isotopic chain.","feed_headline":"Two lost gamma rays placed in tin-114's decay scheme","feed_subtitle":"Coincidence data from GRIFFIN tie the 856.2- and 1405.0-keV lines to the deformed 0+3 state.","key_machinery":"The mechanism that carries the argument is gamma-gamma coincidence gating: GRIFFIN records gamma rays within a 250 ns coincidence window, and the add-back spectrum in coincidence with a selected transition shows only transitions that share a decay cascade. Here the gate on 856.2 keV selects events in which that gamma ray is emitted, and the appearance of 1299.8 keV and 1405.0 keV in that gated spectrum is what fixes the relative energies and ordering of the levels. The same method underlies the newly observed transitions seen in the 1299.8-keV gated spectrum, which the authors plan to place in the full level-scheme analysis.","core_discovery":"The central discovery is that two gamma transitions observed but never placed in earlier beta-decay work are now fixed in the 114Sn level scheme by coincidence: gating on 856.2 keV reveals the 1299.8-keV ground-state transition and a 1405.0-keV transition, establishing that 856.2 keV depopulates the 0+3 state at 2156.0 keV to the 2+1 state, and that 1405.0 keV feeds that state from 3561.0 keV. This places the decay of the deformed 0+3 intruder state in the beta-decay path and anchors the cascade used to study shape coexistence in this semi-magic nucleus.","pith_inferences":["If the cascade is confirmed, the 3561.0-keV state is a natural candidate for the next member of the 2p-2h intruder band built on the 0+3 state; a lifetime measurement of this state could test whether it has the enhanced collectivity expected for a deformed band member.","The same gating strategy could be applied to known (p,p'gamma) and (n,n'gamma) datasets to cross-check whether the 3561.0-keV state appears in those reactions, tying the beta-decay and in-beam studies together.","A purified beam without the 114In and 95Sr19F components would permit a cleaner test of the 856.2-keV gate and may reveal additional weak transitions to or from the 0+3 state that are currently hidden under the cocktail background.","The energy sum 1405.0 + 856.2 + 1299.8 = 3561.0 keV is consistent within rounding; if a later high-precision measurement finds a small discrepancy, the cascade order or a doublet in one of the transitions would need revision."],"forward_implications":["If the placement holds, the 0+3 state at 2156.0 keV is firmly connected to the ground-state band through the 2+1 level, fixing its decay branch in the beta-decay path.","The 1405.0-keV transition places a level at 3561.0 keV above the 0+3 state, and future log ft and angular-correlation analysis can determine its spin and parity.","The coincidence spectrum gated on 1299.8 keV shows several newly observed transitions that the authors state will be incorporated into an expanded level scheme beyond 4 MeV, extending the experimental reach of shape-coexistence studies in 114Sn.","The demonstrated quality of the GRIFFIN beta-decay data makes it possible to measure branching ratios and log ft values for the deformed intruder states, quantities that constrain the mixing between spherical and deformed configurations."],"supporting_citations":[{"why":"Earlier beta-decay study that observed the 856.2- and 1405.0-keV transitions but did not place them in the level scheme.","marker":"[10]"},{"why":"Coulomb excitation experiment that first observed the 2156.0-keV level decaying via the 856.2-keV transition.","marker":"[11]"},{"why":"(p,p'gamma) study that extended the level scheme to 4022.4 keV and investigated shape coexistence via lifetimes.","marker":"[12]"},{"why":"(n,n'gamma) experiment that placed both transitions in the level scheme in that reaction.","marker":"[13]"},{"why":"Describes the GRIFFIN facility and the summing corrections used for calibration and analysis.","marker":"[3]"},{"why":"Characterizes the high-purity germanium clover detectors used for the gamma-ray measurements.","marker":"[4]"}],"fun_headline_variants":["Tin-114 decays finally map its deformed 0+ state","GRIFFIN ties stray gamma rays to tin-114's deformed state","Previously unplaced gamma rays now anchor tin-114 decay","Missing gamma rays in tin-114 finally assigned","Two lost gamma rays find home in tin-114 decay scheme"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The 856.2-keV gate is assumed to be a single, clean transition of 114Sn; if any other gamma ray from the mixed beam or another decay path overlaps it, the coincidences no longer prove the placement.","fun_headline_variants_meta":{"raw":{"variants":["Tin-114 decays finally map its deformed 0+ state","GRIFFIN ties stray gamma rays to tin-114's deformed state","Previously unplaced gamma rays now anchor tin-114 decay","Missing gamma rays in tin-114 finally assigned","Two lost gamma rays find home in tin-114 decay scheme"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.001133,"raw_usage":{"total_tokens":4705,"prompt_tokens":939,"completion_tokens":3766,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":555,"completion_tokens_details":{"reasoning_tokens":3681}},"tokens_in":555,"tokens_out":3766,"duration_ms":24525,"temperature":1.0,"reasoning_tokens":3681,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-16T10:46:59.618439+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Look at the 856.2-keV peak for doublet structure or background contamination and test the reverse gates: gating on 1405.0 keV should reproduce the 1299.8-keV and 856.2-keV lines, and gating on 1299.8 keV should show both. If the 1405.0-keV gate does not show 856.2 keV and 1299.8 keV with consistent relative intensities, the claimed cascade fails.","supporting_citations":[{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Earlier beta-decay study that observed the 856.2- and 1405.0-keV transitions but did not place them in the level scheme."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Coulomb excitation experiment that first observed the 2156.0-keV level decaying via the 856.2-keV transition."},{"cited_title":"Spieker, et al., Shape coexistence and collective low-spin states in112,114Sn studied with the (p,p ′ γ) Doppler- shift attenuation coincidence technique, Phys","cited_arxiv_id":null,"evidence_quote":"(p,p'gamma) study that extended the level scheme to 4022.4 keV and investigated shape coexistence via lifetimes."},{"cited_title":"Araddad, et al., Mixtures of multipoles inγtransitions from the reaction 114Sn(n, n’γ), Bull","cited_arxiv_id":null,"evidence_quote":"(n,n'gamma) experiment that placed both transitions in the level scheme in that reaction."},{"cited_title":"Garnsworthy, et al., The GRIFFIN facility for decay-spectroscopy studies at TRIUMF-ISAC, Nuc","cited_arxiv_id":null,"evidence_quote":"Describes the GRIFFIN facility and the summing corrections used for calibration and analysis."},{"cited_title":"Rizwan, et al., Characteristics of GRIFFIN high-purity germanium clover detectors, Nuc","cited_arxiv_id":null,"evidence_quote":"Characterizes the high-purity germanium clover detectors used for the gamma-ray measurements."}],"review_version":1}