{"id":"21423ddf-3ed4-44d8-aad3-d48c53857e39","arxiv_id":"2411.18057","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":0,"one_line_summary":"Tensor-force effects on quasifission fragment yields appear only for specific isoscalar and isovector tensor coupling values, with SLy5t and T31 showing stronger spherical shell effects than SLy5, T44, and T62.","lead":"Researchers simulated quasifission in 48Ca+249Bk and 48Ti+238U with five Skyrme functionals to test how tensor-force parameters alter fragment yields. They found that only specific tensor coupling settings shift and narrow yields toward spherical shell closures, a result relevant for choosing functionals in superheavy-element reaction modeling.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Attribution of TIJ yield differences to tensor coupling constants is confounded by full refits; the C_J0-C_J1 sensitivity-region claim lacks a control in which only tensor strengths vary.","rationale":"The reader's weakest assumption identifies the same confound: because the TIJ forces are fully refitted, T31/T44/T62 differences cannot be uniquely attributed to C_J0 and C_J1. This is indeed the load-bearing point for the \"specific region\" part of the central claim. The paper has a clean tensor-force control in SLy5 versus SLy5t, so the basic statement that tensor force can affect quasifission shell effects is defensible; my concern is specifically the mapping from five EDFs to a narrow sensitivity region in the two-dimensional tensor-coupling plane. A perturbative SLy5-based tensor scan would settle it without refits. I also note an apparent typo in the abstract: it lists T62, not T31, as giving better agreement with experiment, while Sec. III B and the Conclusions state that T31 is better; this should be corrected, but it is secondary to the attribution issue. No machine-checked verification or released code is offered, so the conditional verdict is appropriate; my suggested test would either strengthen or refute the parameter-space claim, so I do not move the verdict.","tokens_in":21004,"tokens_out":6120,"duration_ms":56084,"concrete_test":"Construct a family of EDFs by taking the SLy5 parametrization and adding only the zero-range tensor terms with strengths adjusted so that (C_J0,C_J1) match the SLy5t, T31, T44, and T62 values, leaving all other SLy5 parameters unchanged. Repeat the TDHF quasifission calculations for 48Ca+249Bk at Ec.m.=234 MeV with the same grid, orientations, and impact-parameter sampling as Sec. III A. If the yield-peak positions and widths group as T31/SLy5t versus T44/T62/SLy5, the tensor-coupling attribution is supported; if they do not reproduce the TIJ grouping, the reported sensitivity region is an artifact of the full refits. A cheaper static first check would be to compare HF single-particle gaps, as in Sec. III A and Fig. 7, for these SLy5-based tensor variants before running the full TDHF grid.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim that tensor effects are \"sensitive only in specific regions\" of the C_J0-C_J1 map rests on comparing T31, T44, and T62 in Sec. III A and on grouping T31 with SLy5t. But the TIJ parametrizations are fully refitted (Sec. II, Ref. [78]); the C_J0 and C_J1 defined in Eq. (2) are combinations of t1, t2, x1, x2, te, and to, so varying them in the TIJ family also changes all central, spin-orbit, and density-dependent Skyrme parameters. The clean SLy5-versus-SLy5t comparison isolates the tensor force, but it provides only one point in the parameter map. The TIJ data, which define the \"specific region\" conclusion, cannot separate the tensor coupling constants from the rest of the refit. The strong similarity between SLy5 (no tensor) and T62 (large C_J0, C_J1) in Sec. III A makes this especially acute: if C-coordinates were the controlling variable, SLy5 and T62 should differ, and the observed identity suggests that other parameters or cancellation effects dominate. Without a control in which only C_J0 and C_J1 vary, the claim that the sensitivity is located in a narrow region of the tensor-coupling map is not established.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper uses TDHF theory to compute quasifission fragment yield distributions for 48Ca+249Bk and 48Ti+238U with several Skyrme energy density functionals: SLy5, SLy5t, and three fully refitted TIJ parametrizations (T31, T44, T62). It reports that SLy5t and T31 produce yield peaks closer to spherical shell closures (N=126, Z=82) and, for 48Ti+238U, narrower distributions, while SLy5, T44, and T62 behave similarly. The authors conclude that tensor forces influence the prominence of shell effects in quasifission and that this influence is confined to a specific region of the isoscalar/isovector tensor coupling constant plane.","tokens_in":21268,"tokens_out":6462,"duration_ms":59983,"significance":"If established, the result is valuable: it connects a specific detail of the Skyrme EDF, the tensor term, to quasifission observables and to the superheavy-element fusion problem. The cleanest comparison, SLy5 versus SLy5t, isolates the tensor contribution in a controlled way and shows a consistent effect across two reaction systems; the 48Ti+238U comparison with experimental data from Ref. [26] is a useful test. The TIJ family adds breadth, but because those parametrizations are fully refitted, the inference to the C_J0-C_J1 plane is not yet controlled. The paper is transparent about computational constraints and explicitly labels its single-particle gap analysis as approximate (Sec. III A), which strengthens credibility.","major_comments":[{"comment":"The central attribution of the T31, T44, and T62 yield differences to the tensor coupling constants is confounded. The TIJ forces are fully refitted (Sec. II, Ref. [78]), and Eq. (2) shows that C_J0 and C_J1 are linear combinations of t1, t2, x1, x2, te, and to; moving among T31, T44, and T62 therefore changes the entire Skyrme EDF, not only the tensor strengths. The observed grouping of SLy5 with T44/T62 and SLy5t with T31 may consequently be driven by other fitted parameters. In particular, Sec. III A notes that SLy5 (no tensor) and T62 (large C_J0, C_J1) give nearly identical yields, which is difficult to reconcile with the C-coordinates being the controlling variable unless the relevant cancellations are demonstrated. A control calculation in which only te and to (or C_J0 and C_J1) are varied while all other parameters are held fixed is needed to support the attribution; without it, the 'specific region' claim in the abstract and Sec. IV is not established.","section":"Secs. II and III A, Figs. 2-4, Eq. (2)"},{"comment":"The conclusion that the influence of tensor forces is 'sensitive only in specific regions' of the C_J0-C_J1 map is under-sampled. Only three TIJ points (T31, T44, T62) plus the SLy5/SLy5t pair are computed, and the TIJ points are isolated corners of the map rather than a systematic grid; no neighboring parametrizations define the boundary of the claimed sensitive region. Given the full-refit confound, the data cannot distinguish a genuinely narrow sensitive region from a threshold effect or from correlations among other Skyrme parameters. The wording should be softened to a statement that the results are consistent with sensitivity near the SLy5t/T31 parameters, or the claim should be supported by additional EDFs that vary only the tensor couplings.","section":"Sec. III A and Sec. IV"},{"comment":"The orientation sampling for the 48Ti+238U system is not fully specified. The text says that two orientations of the prolate 48Ti nucleus are considered and that this 'doubles' the computational effort relative to the 48Ca+249Bk case, but 238U is also prolate deformed; it is not stated whether and how the target orientation was sampled or fixed in this system. Because the yield distributions and the experimental comparison in Figs. 8-11 depend on the averaging in Eq. (4), the ambiguity prevents reproduction and could affect the reported peak shifts and distribution widths.","section":"Sec. III B, Figs. 8-11"},{"comment":"The statement that SLy5t and T31 show 'much better agreement with experimental results' rests on horizontally aligning the theoretical and experimental maxima, with yields in arbitrary units. No quantitative metric (e.g., chi-squared or Kolmogorov-Smirnov distance) or uncertainty estimate is provided, and after arbitrary alignment only the shape and width around the peak can be meaningfully compared. Please provide a quantitative comparison or explicitly present the agreement as qualitative.","section":"Sec. III B, Figs. 9 and 11"}],"minor_comments":[{"comment":"There are typographical errors: 'Sly5t' in the caption of Fig. 8 should be 'SLy5t', and '48Ca+238Bk' in Sec. III B should be '48Ca+249Bk'.","section":"Sec. III B"},{"comment":"In the discussion of Fig. 5, 'most T31 points fall bellow the N=56 line' should read 'below'.","section":"Sec. III A"},{"comment":"The text says the SLy5t and T31 peaks are 'almost perfectly aligned'; it would be clearer to state explicitly whether the full distributions or only the peak centroids are being compared, since the subsequent width discussion is important for the 48Ti+238U case.","section":"Sec. III A and Fig. 4"}],"recommendation":"major_revision","confidential_remarks":"The manuscript is within the scope of the journal and the TDHF calculations appear carefully done, but the load-bearing interpretive step, attributing the TIJ grouping to the C_J0-C_J1 map, needs a controlled comparison. If the authors can add a calculation in which only the tensor strengths vary, or substantially soften the 'specific region' claim, the paper could become acceptable. The orientation-sampling ambiguity for 48Ti+238U should also be resolved before publication."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"First, the gist: this is the follow-up to Li et al.'s 2022 PLB paper, adding three TIJ Skyrme parametrizations and a second reaction (48Ti+238U) with experimental comparison. The cleanest result is the SLy5 vs SLy5t comparison, which isolates the tensor term and shows the tensor force shifts quasifission yields toward the spherical N=126 and Z=82 shells, and in the Ti+U system narrows the distributions. That part is solid.\n\nWhat's genuinely new: the T31/T44/T62 comparison, the grouping into SLy5t/T31 versus SLy5/T44/T62, and the experimental check for 48Ti+238U showing SLy5t and T31 reproduce the charge distribution better than SLy5 and T62. The orientation-averaged TDHF with full impact parameters is computationally heavy, and the authors are honest that the single-particle level analysis is only supplementary.\n\nThe soft spot is the one you'd expect: T31, T44, and T62 are fully refitted EDFs, so the tensor couplings C_J0 and C_J1 change together with all other Skyrme parameters. The SLy5/SLy5t pair gives one clean point, but the \"specific region\" conclusion rests mostly on the TIJ data, which can't separate the tensor coupling constants from the rest of the refit. The stress-test note is right that SLy5 (no tensor) and T62 (large C_J0, C_J1) give nearly identical yields; that weakens the coupling-constant interpretation. The authors' own phrasing is appropriately hedged (\"may be sensitive\", \"warrants further investigation\"), so this is a gap rather than a fatal flaw, but a control calculation or a more explicit discussion of what else changes would strengthen the paper considerably.\n\nMinor issues: the experimental comparison manually aligns the maxima, and there's no quantification of uncertainty, though TDHF is deterministic so that's less pressing.\n\nBottom line: the paper is a credible, honest extension of the group's earlier work, and the second system with experimental data is a real plus. It deserves a serious referee. The referee should ask for a clearer separation of the tensor coupling effect from the full refit, but the SLy5/SLy5t result alone justifies sending it out. I'd cite it, and it's a reasonable candidate for a reading group.","headline":"A solid, honest extension of the group's earlier tensor-force quasifission work, with a real second-system test; the central 'specific region' claim is weakened by the TIJ refit confound but is worth refereeing.","tokens_in":21786,"tokens_out":3224,"would_cite":true,"duration_ms":27603,"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":"Tensor force reshapes quasifission yields only in a narrow parameter region","keywords":["quasifission","tensor force","Skyrme energy density functional","time-dependent Hartree-Fock","shell effects","superheavy elements","yield distributions","isoscalar and isovector tensor couplings"],"falsifier":"Perform TDHF quasifission calculations for a family of Skyrme interactions that vary only $C^J_0$ and $C^J_1$, holding all other parameters fixed at SLy5 values, and test whether the yield peaks shift from the deformed shells to $N=126$/$Z=82$ when the constants move from the T44/T62 corner to the T31 corner; if the grouping disappears, the effect is not carried by the tensor coupling constants themselves.","tokens_in":20803,"feed_emoji":"⚛️","tokens_out":11108,"duration_ms":84180,"temperature":0.7,"pith_summary":"This paper uses time-dependent Hartree-Fock (TDHF) simulations to ask whether the tensor part of the effective nucleon-nucleon interaction changes the products of quasifission reactions, the process that competes with compound-nucleus formation toward superheavy elements. Comparing five Skyrme parametrizations for the reactions $^{48}$Ca+$^{249}$Bk and $^{48}$Ti+$^{238}$U, it finds that the fragment yield distributions fall into two groups: SLy5t and T31 show clearly stronger spherical shell effects, with peaks pulled toward the magic numbers $N=126$ and $Z=82$, while SLy5, T44, and T62 all behave similarly to the original force without tensor terms. The paper concludes that the tensor force's influence on quasifission is not monotonic in the coupling constants: it matters only in a specific region of the isoscalar/isovector tensor coupling-constant space. A careful reader will care because quasifission hinders superheavy element synthesis, and this result says which effective interactions are adequate for describing that hindrance.","feed_headline":"Tensor force reshapes quasifission yields only in a narrow region","feed_subtitle":"Microscopic simulations of two heavy-ion reactions show tensor-force effects are confined to the SLy5t–T31 corner.","key_machinery":"The argument is carried by the Skyrme energy density functional with a two-body tensor interaction, whose strength is summarized by the isoscalar and isovector tensor coupling constants $C^J_0$ and $C^J_1$ (Eq. 2). TDHF evolves Slater-determinant many-body states on a 3D grid for each orientation and impact parameter, and the fragment neutron/proton numbers are histogrammed into yield distributions (Eq. 4). The comparison across SLy5, SLy5t, and the three TIJ parametrizations (T31, T44, T62) is what isolates the tensor-force effect; the yield peaks at magic numbers and the width of the distributions are the readout of shell-effect prominence.","core_discovery":"In the paper's own terms, the central discovery is that 'the influence of tensor forces on quasifission fragments is reflected in the prominence of shell effects,' and this influence appears to be sensitive only in specific regions within the isoscalar and isovector coupling constant parameter space. Concretely, for $^{48}$Ca+$^{249}$Bk the neutron and proton yield distributions computed with SLy5t and T31 cluster around the spherical shell closures $N=126$ and $Z=82$, whereas SLy5, T44, and T62 produce peaks close to the deformed shells ($N=56$, $Z=36$). In $^{48}$Ti+$^{238}$U the same grouping appears, and in addition the SLy5t/T31 yields are narrower around the spherical shells, a second signal of stronger shell effects. The charge distributions from the TDHF runs are compared with the experimental data of Ref. [26]; the body text states that the SLy5t yield matches experiment better than SLy5, and that T31 matches better than T62, although the abstract lists the pairing as SLy5t/T62 versus SLy5/T31, an inconsistency the authors should correct. The paper also explores single-particle level gaps for one collision event, but explicitly labels that analysis as supplementary rather than definitive evidence.","pith_inferences":["Editor's note: the abstract assigns the better experimental charge-distribution match to 'SLy5t and T62' versus 'SLy5 and T31,' while the body text (Figs. 9 and 11 and Sec. IV) assigns it to SLy5t over SLy5 and T31 over T62; the abstract pairing is presumably a typographical error and should be corrected before the results are quoted.","The 'sensitive region' conclusion rests on only five points in the $C^J_0$–$C^J_1$ plane; a systematic scan with all other Skyrme parameters held fixed (e.g., by building a TIJ-style family that varies only the tensor coupling constants) would test whether the T31 boundary is truly where the effect switches on.","The same shell-effect mechanism should be visible in fission fragment yields from actinide nuclei, since those also reflect the competition between spherical and deformed shell gaps; a TDHF fission calculation with SLy5t versus SLy5 would give a testable prediction.","The observed threshold that shell effects dominate only for contact times longer than about 5 zs suggests that experiments at higher bombarding energies or with lighter projectiles, which produce shorter contact times, should show little sensitivity to the tensor force."],"forward_implications":["For $^{48}$Ca+$^{249}$Bk, using SLy5t or T31 instead of SLy5/T44/T62 shifts predicted quasifission fragment peaks toward the spherical magic numbers $N=126$ and $Z=82$.","For $^{48}$Ti+$^{238}$U, the same functional choice narrows the quasifission yield distribution around $Z=82$, a second experimental fingerprint of the tensor force.","Because quasifission competes with fusion, the choice of Skyrme parametrization changes predictions for superheavy-element formation cross sections in hot-fusion reactions.","The grouping of T44/T62 with the no-tensor SLy5 implies that large tensor coupling constants alone do not change quasifission; the sign/combination matters, locating the sensitive region near negative $C^J_1$.","The method of reading shell-effect strength from yield-peak location and width can be applied to other deformed target/projectile combinations for which experimental charge distributions exist."],"supporting_citations":[{"why":"Establishes the baseline TDHF quasifission result for $^{48}$Ca+$^{249}$Bk with SLy5 and SLy5t, including the shift toward spherical shell effects that this paper extends to TIJ forces.","marker":"[54]"},{"why":"Provides the TIJ family of Skyrme parametrizations (T31, T44, T62) with full refitting of all parameters including the tensor terms, and defines the $C^J_0$/$C^J_1$ map used for the comparison.","marker":"[78]"},{"why":"Supplies the SLy5t interaction, the perturbatively tensor-extended version of SLy5.","marker":"[75]"},{"why":"Supplies the SLy5 parametrization without tensor force, the baseline for the SLy5t comparison.","marker":"[95]"},{"why":"Provides the experimental charge distribution for $^{48}$Ti+$^{238}$U against which the TDHF yields are compared.","marker":"[26]"},{"why":"Reports the earlier TDHF quasifission calculation for $^{48}$Ca+$^{249}$Bk using SLy4d, whose deformed-shell behavior the SLy5 results replicate.","marker":"[64]"},{"why":"Explains the Eulerian rotation method used to orient the deformed $^{249}$Bk and $^{238}$U nuclei in the TDHF runs.","marker":"[101]"},{"why":"Provides the unrestricted 3D TDHF framework on a Cartesian grid used for the dynamical evolution.","marker":"[96]"}],"fun_headline_variants":["Tensor forces steer quasifission only near spherical shells","Quasifission yields show tensor effect only in one corner","Narrow tensor-force window shapes heavy-ion yields","Shell effects gate tensor influence on quasifission","Tensor force impact on quasifission is selective"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The paper attributes the yield differences between T31, T44, and T62 to their isoscalar and isovector tensor coupling constants, but these parametrizations were fully refitted and differ in all other Skyrme parameters simultaneously, so if those other parameter changes drive the effect the central claim about a sensitive region in the coupling-constant map would lose support.","fun_headline_variants_meta":{"raw":{"variants":["Tensor forces steer quasifission only near spherical shells","Quasifission yields show tensor effect only in one corner","Narrow tensor-force window shapes heavy-ion yields","Shell effects gate tensor influence on quasifission","Tensor force impact on quasifission is selective"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000296,"raw_usage":{"total_tokens":1829,"prompt_tokens":1167,"completion_tokens":662,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":783,"completion_tokens_details":{"reasoning_tokens":587}},"tokens_in":783,"tokens_out":662,"duration_ms":5704,"temperature":1.0,"reasoning_tokens":587,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-12T11:33:07.727790+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Perform TDHF quasifission calculations for a family of Skyrme interactions that vary only $C^J_0$ and $C^J_1$, holding all other parameters fixed at SLy5 values, and test whether the yield peaks shift from the deformed shells to $N=126$/$Z=82$ when the constants move from the T44/T62 corner to the T31 corner; if the grouping disappears, the effect is not carried by the tensor coupling constants themselves.","supporting_citations":[{"cited_title":"Godbey and A","cited_arxiv_id":null,"evidence_quote":"Establishes the baseline TDHF quasifission result for $^{48}$Ca+$^{249}$Bk with SLy5 and SLy5t, including the shift toward spherical shell effects that this paper extends to TIJ forces."},{"cited_title":"Hellemans, P.-H","cited_arxiv_id":null,"evidence_quote":"Provides the TIJ family of Skyrme parametrizations (T31, T44, T62) with full refitting of all parameters including the tensor terms, and defines the $C^J_0$/$C^J_1$ map used for the comparison."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Supplies the SLy5t interaction, the perturbatively tensor-extended version of SLy5."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Supplies the SLy5 parametrization without tensor force, the baseline for the SLy5t comparison."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Provides the experimental charge distribution for $^{48}$Ti+$^{238}$U against which the TDHF yields are compared."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Reports the earlier TDHF quasifission calculation for $^{48}$Ca+$^{249}$Bk using SLy4d, whose deformed-shell behavior the SLy5 results replicate."},{"cited_title":"Stevenson, Y","cited_arxiv_id":null,"evidence_quote":"Explains the Eulerian rotation method used to orient the deformed $^{249}$Bk and $^{238}$U nuclei in the TDHF runs."},{"cited_title":"Chabanat, P","cited_arxiv_id":null,"evidence_quote":"Provides the unrestricted 3D TDHF framework on a Cartesian grid used for the dynamical evolution."}],"review_version":1}