{"id":"cc053bbe-a58c-4089-917b-c19707e8f5aa","arxiv_id":"1908.10900","paper_version":1,"verdict":"UNVERDICTED","confidence":"HIGH","novelty_score":2.0,"correctness_risk":"low","formal_verification":"none","parameter_count":3,"one_line_summary":"A review of BSM Higgs models concludes that current LHC data imply near-alignment, leaving room for lighter or heavier additional scalars and specific untested signatures.","lead":"A conference review of beyond-Standard-Model Higgs sectors concludes that LHC data force the 125 GeV Higgs to look almost exactly like the Standard Model one, but still allow extra, as yet unprobed scalar states. It is a useful map of which new Higgs signatures the HL-LHC should target.","discovery_kind":"review","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The h/H distinguishability claim in Sec. 3.1 rests on an under-justified bound m^2 ≲ O(v^2); if the bound is weaker at large tanβ, the -10% H→γγ shift is not robust.","rationale":"The reader correctly identified the m^2 bound as the weakest step in the h-versus-H distinguishability argument. My analysis confirms this is the most load-bearing technical assumption in the paper's original content. However, I find that the bound is likely correct for the scenario considered: the requirement that the lighter CP-even state h has mass below 125 GeV, combined with the positivity of the CP-even mass matrix and bounded quartic couplings, forces m^2 to be at most O(v^2) (with the precise coefficient depending on tanβ). Thus the reader's worry that 'the bound could fail' is not a genuine failure but an incompletely justified and potentially benchmark-dependent statement. The concrete test would settle whether the numerical claim of 'around -10%' is universal or limited to a subregion of the allowed parameter space. The paper's central conclusion — that LHC data imply an approximate alignment limit and that there remains room for new Higgs discoveries — is independently supported by the singlet-sector analyses and by the H±→W±h argument, which does not rely on the m^2 bound. Therefore, this concern does not overturn the review's overall message; it calls for a quantitative caveat in Sec. 3.1. Since the paper is classified as a review and the existing UNVERDICTED verdict reflects that genre, no verdict change is warranted.","tokens_in":8769,"tokens_out":31184,"duration_ms":296580,"concrete_test":"Reproduce the Type-I 2HDM scan underlying Fig. 3 with M_H = 125 GeV, M_h < M_H, imposing unitarity, boundedness, perturbativity, and HiggsBounds/HiggsSignals constraints. For M_H± between 400 and 700 GeV, record m^2/M_H±^2 and the exact BR(H→γγ)/BR(h_SM→γγ) for all allowed points. If any allowed point has m^2/M_H±^2 ≥ 0.5 or a rate modification differing from -10% by more than a factor of two, the non-decoupling argument as stated is not robust. Alternatively, derive analytically the maximum m^2 allowed by the CP-even mass-matrix determinant and perturbative bounds |λ_i| ≤ 8π, and compare it to M_H±^2 in the high-M_H± region.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The paper's most original claim is that a 2HDM with the heavy CP-even H as the 125 GeV state can be distinguished from the standard h-as-125 picture through the non-decoupling charged-Higgs loop in H→γγ. Equation (3.3) gives g_{HH+H-} → -2 M_H±^2/v for M_H± ≫ M_H, and the justification is that m^2 ≡ 2m12^2/sin2β is ≲ O(v^2) 'imposed by unitarity and stability conditions'. This bound is load-bearing: if instead m^2 could be of order M_H±^2, the -2m^2 term would cancel the -2M_H±^2 term, drastically suppressing the H→γγ modification. The bound is not a direct consequence of unitarity/stability alone; it follows from the mass ordering M_h < M_H = 125 GeV together with perturbativity of the quartic couplings. In the limit tanβ ≫ 1 the effective bound is relaxed, scaling like v^2/sin2β, so there could be allowed regions where the -10% shift is not representative. The paper does not quantify the bound or show that such regions are excluded from Fig. 3, leaving the general statement 'around -10% at large MH±' under-supported.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek-v4-flash","summary":"This proceedings paper reviews BSM Higgs sectors in increasing complexity: a real singlet extension, two real singlets, the CP-conserving 2HDM, and the MSSM Higgs sector. It uses the public codes HiggsBounds and HiggsSignals, together with published benchmark scans, to translate current LHC Higgs rate measurements and searches into constraints. The main quantitative results are the allowed region in (kappa, BR(h125 -> hS hS)) for the singlet, maximal rates for pp -> hS -> h125 h125, Higgs-to-Higgs decay benchmark planes for the two-singlet model, a Type-I 2HDM scan with the heavy CP-even state H as the 125 GeV boson, and HL-LHC MSSM H/A -> tau tau projections. The paper concludes that current data require approximate alignment (SM-like couplings for the 125 GeV state) but leave room for additional lighter or heavier scalars and for so-far-uncovered signatures such as H+/- -> W+/- h, hi -> hj hk cascades, and H/A -> neutralino/chargino decays.","tokens_in":9041,"tokens_out":13966,"duration_ms":150164,"significance":"If the 2HDM distinguishability claim holds, the paper identifies a testable and non-decoupling signature: the charged-Higgs loop correction to H -> gamma gamma and the dominance of H+/- -> W+/- h in the H-as-125 interpretation. This is a timely observation that could motivate dedicated searches. The review is useful as a compact summary of the HL-LHC BSM Higgs landscape, and it benefits from the use of publicly released tools (HiggsBounds/HiggsSignals) and from reproducible published benchmark planes in Refs. [10], [14], and [1]. The Higgs-to-Higgs-decay benchmark planes and the explicit upper limit on BR(h125 -> NP) are concrete, falsifiable predictions. However, the paper's most original claim is not self-contained: it rests on an unpublished scan (Ref. [19]) and on a one-line bound on m^2 that is not established in the text, so the significance is currently conditional on the documentation of that analysis.","major_comments":[{"comment":"The crucial bound m^2 = 2 m12^2 / sin(2 beta) <= O(v^2), described as 'imposed by unitarity and stability conditions', is not derived and, as stated, is not an immediate consequence of either condition; unitarity and stability constrain the quartic couplings, not the soft-breaking mass m12^2 directly. Using the standard relation M_H+-^2 = m^2 - (lambda4 + lambda5) v^2 / 2, a large charged-Higgs mass is consistent with m^2 ~ M_H+-^2, in which case the two '-2 M_H+-^2' contributions in Eq. (3.3) cancel and the H -> gamma gamma loop decouples rather than approaching -10%. The limit M_H+- >> M_H used in Eq. (3.3) therefore requires an additional alignment condition or a quantitative perturbativity bound on lambda4 + lambda5 that the text does not state. Please supply this derivation, state the precise criterion, and identify the region of parameter space in which the -10% result holds.","section":"Sec. 3.1, Eq. (3.3)"},{"comment":"Fig. 3 and the accompanying statements that the H -> gamma gamma modification is 'around -10% at large M_H+-' and that H+/- -> W+/- h is 'generally dominant' are based on a parameter scan whose ranges and constraint implementation are not described in this paper; the details are deferred to Ref. [19], which is in preparation. Because the h-versus-H distinguishability conclusion is the paper's most original claim, the reader cannot assess the scan coverage (for example the ranges of tan beta, Mh, and m12^2, and the treatment of perturbative unitarity, boundedness, and electroweak precision constraints) or reproduce the allowed-point ensembles. Either include the scan details and constraints or explicitly frame the -10% and H+/- -> W+/- h dominance statements as benchmark-specific expectations from Ref. [19].","section":"Sec. 3.1, Fig. 3"},{"comment":"The soft-breaking combination m^2 = 2 m12^2 / sin(2 beta) grows like m12^2 tan beta for tan beta >> 1, so the bound m^2 <= O(v^2) is not parameter-independent. The manuscript does not state the tan beta range used in the Fig. 3 scan; the text only notes that tan beta >~ 2 is essentially unconstrained by flavor observables in Type-I. If the scan excludes or does not cover the large-tan beta region, the statement that the H -> gamma gamma rate is modified by about -10% at large M_H+- is not a general 2HDM conclusion. A quantified bound, or a demonstration that the relaxed regions are excluded by the scan, is needed to support the distinguishability claim.","section":"Sec. 3.1, large-tan beta regime"}],"minor_comments":[{"comment":"The text uses both 'Type-1' and 'Type-I' for the same fermion coupling scenario; please unify the notation.","section":"Sec. 3.1"},{"comment":"The charged-Higgs mass is written both as M_H+ and as M_H+-; please use a single symbol consistently in equations, captions, and running text.","section":"Sec. 3.1, Eq. (3.3) and Fig. 3"},{"comment":"The statement that the HL-LHC is expected to become sensitive to pp -> hS -> h125 h125 for hS masses below about 500 GeV should cite the projection source, as is done for the BR(H -> NP) limit in the same section.","section":"Sec. 2.1"},{"comment":"The text contains the typo 'threrefore', and the benchmark scenarios M_h^125 and M_h^125(chi tilde) should be defined at first use rather than only referenced.","section":"Sec. 3.2"},{"comment":"The acknowledgment contains a garbled character in the German Research Foundation grant string; please repair the encoding.","section":"Acknowledgments"}],"recommendation":"major_revision","confidential_remarks":"To the editor: this manuscript is a workshop proceedings review rather than a full research article; most quantitative results are already published in Refs. [1], [10], [14], and [20]. The genuinely new element is the 2HDM h-versus-H distinguishability scan, which is currently supported by an in-preparation paper by the same group. If the journal's scope includes proceedings-style reviews, the paper is suitable after revision; for a regular research journal, the novelty is thin. The Sec. 3.1 technical issue should be resolved before publication: either provide the derivation and scan details or moderate the general claims. The reliance on the author's own public tools is not in itself a problem, but the in-preparation status of Ref. [19] makes the central figure non-reproducible."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"Candid take: this is a workshop proceedings review, not a research paper. It reads clearly and collects useful constraints for singlet extensions, the 2HDM, and the MSSM. The conclusion that LHC data push BSM scalar sectors toward an alignment limit while leaving room for extra states is correct and well supported by the cited analyses. The figures from HiggsBounds/HiggsSignals and the two-singlet companion paper are reproduced honestly, and the discussion of Higgs-to-Higgs cascades and H±→W±h is genuinely useful for planning HL-LHC searches. As a review, it earns its place.\n\nThe soft spots are in Section 3.1. The claim that an H-at-125 2HDM can be distinguished via the non-decoupling charged-Higgs loop in H→γγ is interesting, but the argument as printed leans on Eq. (3.3), which assumes m² ≡ 2m12²/sin2β ≲ O(v²) \"imposed by unitarity and stability.\" That is not a direct consequence of unitarity and stability; it also needs the mass ordering and perturbative couplings, and the bound weakens at large tanβ. The stress-test note is right about this. The paper neither derives the bound nor shows that the regions where it fails are excluded from Fig. 3. So the general statement of \"around −10% at large MH±\" should be treated as a plausibility claim, not a proven benchmark. The right fix is to point to the derivation in the in-preparation Ref. [19], or to show a scan that excludes the offending parameter region.\n\nThe other caveat is the heavy reliance on the author's own tools and companion papers. That is not a flaw when the tools are public and the prior results are published; HiggsBounds and HiggsSignals are well known. But it means the review's added value is synthesis, not new analysis.\n\nBottom line: I would get this into the proceedings as a useful overview. If this were a journal submission, I would send it to a referee who can check Eq. (3.3) and the tanβ-dependence before accepting. For the workshop, no need to block.","headline":"A competent, clearly written workshop review that is worth reading for the HL-LHC planning, but its most interesting claim—2HDM h-vs-H discrimination via H→γγ—rests on an unquantified bound in Eq. (3.3) and should be treated as provisional until the in-preparation paper appears.","tokens_in":9608,"tokens_out":2355,"would_cite":false,"duration_ms":24944,"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":"LHC measurements of the 125 GeV Higgs force beyond-Standard-Model scalar sectors into an approximate alignment limit, yet leave room for new Higgs states and signatures that upcoming runs could discover.","keywords":["Higgs boson","beyond Standard Model","two-Higgs-doublet model","alignment limit","scalar singlet extension","MSSM Higgs sector","Higgs-to-Higgs decays","HL-LHC"],"falsifier":"An HL-LHC measurement of the 125 GeV diphoton rate that matches the Standard Model within a few percent, while a charged Higgs is known or assumed to exist below 1 TeV, would rule out the H-at-125 interpretation, as would a dedicated $H^\\pm\\to W^\\pm h$ search that excludes the model's predicted order-one branching ratios across the allowed mass plane.","tokens_in":8524,"feed_emoji":"⚛️","tokens_out":13154,"duration_ms":129667,"temperature":0.7,"pith_summary":"This review asks what current LHC measurements of the 125 GeV Higgs boson and searches for additional scalars imply for simple beyond-Standard-Model scalar sectors: singlet extensions, the two-Higgs-doublet model, and the Minimal Supersymmetric Standard Model. The paper's central message is that all of these models are forced into an approximate alignment limit, meaning the observed Higgs boson must have tree-level couplings to W, Z, and fermions very close to the Standard Model's. The paper argues that this constraint still leaves room for new physics, including lighter scalars, Higgs-to-Higgs decays, charged-Higgs decays to a W and a light Higgs, and heavy neutral Higgs decays to neutralinos and charginos. A specific conclusion is that, in the two-Higgs-doublet model, the two possible alignments are experimentally distinguishable through a non-decoupling charged-Higgs contribution to the diphoton rate.","feed_headline":"LHC Higgs data push BSM models into the alignment limit","feed_subtitle":"Yet the same models still hide new scalars and cascade decays that the HL-LHC could reveal.","key_machinery":"The central object is the alignment limit of a two-Higgs-doublet model: when $\\sin(\\beta-\\alpha)\\to 1$ the lighter state $h$ has Standard-Model-like couplings, and when $\\cos(\\beta-\\alpha)\\to 1$ the heavier state $H$ does. The argument that separates these two cases is a non-decoupling relation for the charged-Higgs coupling in the $H$-aligned limit, $g_{HH^+H^-}\\to -2M_{H^\\pm}^2/v$, which holds because the soft mass parameter $m^2\\equiv 2m_{12}^2/\\sin(2\\beta)$ is bounded by $\\mathcal{O}(v^2)$ from unitarity and vacuum stability. This coupling prevents the charged-Higgs loop from vanishing as $M_{H^\\pm}$ grows, leaving a measurable suppression of about 10% in $H\\to\\gamma\\gamma$. In the singlet models, the analogous machinery is a universal suppression of all Standard Model couplings by a mixing-angle factor, which lets measured Higgs rates be translated directly into limits on singlet mixing and on Higgs-to-Higgs decay rates.","core_discovery":"The paper's central claim is that the absence of new scalar signals plus the measured properties of the 125 GeV state do not simply close the book on beyond-Standard-Model Higgs sectors; they place those sectors in an approximate alignment limit and, at the same time, leave open a set of signatures that current searches have not covered. In the two-Higgs-doublet model, the paper shows that the two possible alignments are distinguishable: if the heavier $H$ is the 125 GeV state, the charged-Higgs loop in $H\\to\\gamma\\gamma$ cannot decouple, producing a roughly 10% rate suppression, and $H^\\pm\\to W^\\pm h$ becomes the dominant charged-Higgs decay over most of the allowed Type-I parameter space. In singlet extensions, Higgs rate measurements bound the singlet mixing to $g/g_{\\rm SM}\\lesssim 0.26$ and cap any new-physics decay of the 125 GeV state at a branching ratio of about 7%, while resonant $h_2\\to h_1h_1$ production remains beyond current search sensitivity. In the Minimal Supersymmetric Standard Model, $\\tau^+\\tau^-$ searches for $H/A$ will cover heavy Higgs masses below about 1 TeV at the high-luminosity LHC, except where those states decay to neutralinos and charginos, a channel in need of dedicated searches.","pith_inferences":["A testable extension of the h-versus-H argument would combine the diphoton rate with other loop-induced couplings such as $H\\to Z\\gamma$, since the same non-decoupling charged-Higgs loop should enter both and could discriminate the two alignments with less integrated luminosity than the diphoton channel alone.","The paper leaves implicit that the $\\mathrm{BR}(H\\to\\mathrm{NP})\\lesssim 7\\%$ bound in the singlet model can be read as a generic cap on any exotic or invisible decay of the 125 GeV Higgs induced by mixing with a hidden scalar, and tightening it to the projected 4% would make the constraint comparable to the strongest direct invisible-Higgs searches.","A concrete search strategy suggested by the two-singlet benchmark planes is to optimize existing multi-$b$-tag analyses for the three- and four-$b$-jet final states of the $h_3\\to h_2h_2\\to h_1h_1h_1h_1$ cascade, since the paper identifies the softness of the final state as the main experimental challenge."],"forward_implications":["New scalar states discovered at the LHC will characteristically have suppressed couplings to fermions and gauge bosons, so they are more likely to surface in Higgs-to-Higgs cascades or diboson final states than in standard Higgs-like single-production searches.","A precise high-luminosity LHC measurement of $H\\to\\gamma\\gamma$ can probe charged-Higgs masses far above the direct reach, because the predicted suppression grows with $M_{H^\\pm}$ instead of decoupling.","Dedicated searches for $H^\\pm\\to W^\\pm h$ are required to decide whether the observed 125 GeV state is the lighter or the heavier CP-even scalar of a two-Higgs-doublet model.","In the Minimal Supersymmetric Standard Model, the high-luminosity LHC will cover essentially all $H/A\\to\\tau^+\\tau^-$ signatures below about 1 TeV, making the $H/A\\to$ neutralino/chargino channel the principal remaining blind spot.","Resonant double-Higgs production from a heavy singlet is currently unconstrained, so the high-luminosity phase of the LHC, not Run 2, is the first real opportunity to discover that signature."],"supporting_citations":[{"why":"Supplies the high-luminosity LHC projection setup and the Higgs self-coupling sensitivity discussion that frame the review's future-reach statements.","marker":"[1]"},{"why":"Provides the public tool used to test the models against experimental limits from LHC Higgs searches.","marker":"[7]"},{"why":"Provides the public tool used to test the models against measured Higgs signal rates.","marker":"[8]"},{"why":"Supplies the detailed singlet-extension phenomenology whose constraints and maximal rates are shown in the paper.","marker":"[10]"},{"why":"The LHC search combination for resonant $h_2\\to h_1h_1$ production that defines the current sensitivity against which the singlet-model rate is compared.","marker":"[12]"},{"why":"Provides the two-singlet benchmark planes and the cascade rates featuring $h_3\\to h_1h_2$ and $h_3\\to h_2h_2$ signatures.","marker":"[14]"},{"why":"Establishes that the charged-Higgs contribution to $H\\to\\gamma\\gamma$ neither decouples at large $M_{H^\\pm}$ nor vanishes in the alignment limit, which is the basis of the h-versus-H distinction.","marker":"[17]"},{"why":"Gives the flavor constraint $M_{H^\\pm}\\gtrsim 600$ GeV in Type-II that motivates focusing the light-charged-Higgs discussion on Type-I.","marker":"[18]"},{"why":"The proposed dedicated search for $H^\\pm\\to W^\\pm h$ that the paper argues is needed to tell the h-at-125 and H-at-125 interpretations apart.","marker":"[19]"},{"why":"Defines the Mh125 and Mh125(chi) benchmark scenarios used to project the high-luminosity LHC reach in the Minimal Supersymmetric Standard Model.","marker":"[20]"}],"fun_headline_variants":["Alignment limit: BSM Higgs still hiding new scalars","New scalars lurk beyond current LHC reach in BSM Higgs","BSM Higgs: alignment limit masks new physics, HL-LHC to probe","HL-LHC to catch BSM Higgs decays hidden from current probes","BSM Higgs sectors align, hide new scalars from LHC"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The h-versus-H distinguishability argument depends on the soft mass parameter $m^2 \\equiv 2m_{12}^2/\\sin(2\\beta)$ being bounded by roughly the weak scale, as unitarity and stability require; if that parameter could be much larger, the charged-Higgs coupling would decouple and the predicted diphoton-rate shift would not occur.","fun_headline_variants_meta":{"raw":{"variants":["Alignment limit: BSM Higgs still hiding new scalars","New scalars lurk beyond current LHC reach in BSM Higgs","BSM Higgs: alignment limit masks new physics, HL-LHC to probe","HL-LHC to catch BSM Higgs decays hidden from current probes","BSM Higgs sectors align, hide new scalars from LHC"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000725,"raw_usage":{"total_tokens":3241,"prompt_tokens":926,"completion_tokens":2315,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":542,"completion_tokens_details":{"reasoning_tokens":2223}},"tokens_in":542,"tokens_out":2315,"duration_ms":17836,"temperature":1.0,"reasoning_tokens":2223,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-14T10:30:44.955414+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"An HL-LHC measurement of the 125 GeV diphoton rate that matches the Standard Model within a few percent, while a charged Higgs is known or assumed to exist below 1 TeV, would rule out the H-at-125 interpretation, as would a dedicated $H^\\pm\\to W^\\pm h$ search that excludes the model's predicted order-one branching ratios across the allowed mass plane.","supporting_citations":[{"cited_title":"Stefaniak, J","cited_arxiv_id":null,"evidence_quote":"The proposed dedicated search for $H^\\pm\\to W^\\pm h$ that the paper argues is needed to tell the h-at-125 and H-at-125 interpretations apart."}],"review_version":1}