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arxiv: 2604.25998 · v1 · submitted 2026-04-28 · ✦ hep-ph

Recognition: unknown

New insights into the brightarrow c bar{u}q puzzle through Top-Bottom synergies

Jack Y. Araz , Christoph Englert , Matthew Kirk , Gilberto Tetlalmatzi-Xolocotzi
Authors on Pith no claims yet

Pith reviewed 2026-05-07 15:51 UTC · model grok-4.3

classification ✦ hep-ph
keywords non-leptonic B decaysb to c u q transitionscharged Higgs bosonsSU(2) scalar doubletsB meson anomaliesQCD power correctionstop pair production
0
0 comments X

The pith

Collider bounds on scalar doublets resist relaxation from top-pair rates

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper explores whether anomalies in non-leptonic B decays can be explained by new physics in the form of additional SU(2)_L scalar doublets. It conducts collider analyses to check if raising the branching ratio to top pairs, adding large power corrections to QCD factorisation, or using multi-scalar setups can evade existing constraints. The results indicate that charged Higgs searches maintain strong bounds even when ttbar modes become more prominent, and the other model-building routes also fail to open viable space. A reader cares because these discrepancies between bottom decays and the Standard Model would point to new particles if they cannot be reconciled with current data.

Core claim

Additional SU(2)_L scalar doublets cannot easily accommodate the non-leptonic B decay anomalies because collider bounds from charged Higgs and ttbar searches remain robust even with increased top-pair branching ratios, and typical extensions via power corrections or multiple scalars stay constrained by measurements.

What carries the argument

The top-bottom synergy in models with extra weak scalar doublets, where bottom-quark decay rates are linked to collider signatures in charged Higgs and ttbar final states.

Load-bearing premise

New physics effects are captured by additional SU(2)_L scalar doublets whose collider signatures are dominated by charged Higgs and top-pair production without compensating contributions from the rest of the model spectrum.

What would settle it

Observation of a charged Higgs boson in the relevant mass range and with couplings that simultaneously fit the B-decay anomalies while respecting current ttbar limits, or a clear excess in ttbar rates that matches the required branching without violating other searches.

Figures

Figures reproduced from arXiv: 2604.25998 by Christoph Englert, Gilberto Tetlalmatzi-Xolocotzi, Jack Y. Araz, Matthew Kirk.

Figure 1
Figure 1. Figure 1: FIG. 1. Bounds on the couplings of the charged (left) and CP-even neutral (right) components of the extra doublet from our view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Effect of turning on additional view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Comparing the collider limits from decays of the charged (blue) and neutral (orange) components of the additional view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. BSM regions for different numbers of additional dou view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. BSM regions for 0, 5 and 10 per cent power correc view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. BSM regions for different numbers of additional doublets, each with the same BSM coupling structure, and different view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7. Comparison of exclusion limits on the Yukawa cou view at source ↗
read the original abstract

Anomalies in the non-leptonic $\bar{B}^0\rightarrow D^{(*)+}K^{(*)-}$ and $\bar{B}^0_s\rightarrow D^{(*)+}_s\pi^-$ decays may be an indication of physics beyond the Standard Model, but the large deviations require strongly coupled new physics that should be visible at colliders. We explore three new directions that could lead to viable new physics models, performing a detailed collider study to examine the possible weakening of previously known constraints on additional $SU(2)_L$ doublets. Our results show that, despite the difficulty of probing $t\bar{t}$ final states, increasing the branching ratio to this decay mode does not significantly weaken the bounds on weak doublet scalars, as additionally existing charged Higgs searches are equally strong. Beyond this, we analyse a potentially large breakdown of QCD factorisation by including large-power corrections to $B$ decays, and the effect of diluting collider searches with multi-scalar extensions. We find that these typical model-building routes for constructing a viable scenario remain constrained by collider measurements, indicating that these non-leptonic anomalies remain among the most puzzling discrepancies from the SM.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 3 minor

Summary. The manuscript examines anomalies in non-leptonic B decays (B0 → D(*)K(*)- and Bs → Ds(*)π-) that deviate from Standard Model expectations and may indicate strongly coupled new physics. Focusing on extensions with additional SU(2)_L scalar doublets, the authors investigate three potential resolutions: (i) increasing the branching ratio to ttbar final states, (ii) incorporating large power corrections to QCD factorization in B decays, and (iii) diluting collider signals via multi-scalar spectra. Through detailed LHC recasts of charged Higgs and top-pair searches plus parameter scans, they conclude that these routes do not sufficiently relax existing bounds, leaving the anomalies in tension with collider data.

Significance. If the numerical results hold, the work demonstrates the robustness of LHC constraints against standard model-building strategies, reinforcing the difficulty of reconciling non-leptonic B anomalies with simple BSM scenarios. Credit is given for the concrete collider recasts, the inclusion of power-correction estimates, and the multi-doublet dilution scans, which provide falsifiable, quantitative limits rather than qualitative arguments. This strengthens the case that these flavor discrepancies remain among the more puzzling deviations from the SM.

minor comments (3)
  1. The abstract and introduction refer to the 'b→c ūq puzzle' without a dedicated reference to the specific experimental measurements or anomaly significance; adding one or two key citations (e.g., to the relevant LHCb or Belle papers) would improve context.
  2. In the collider simulation section (likely §3 or §4), the Monte Carlo tools, parton-shower settings, and luminosity assumptions used for the ttbar and charged-Higgs recasts are not stated explicitly; this information is needed for reproducibility of the exclusion contours.
  3. Figure captions for the multi-scalar dilution plots should clarify the exact number of doublets scanned and the color coding for different mass hierarchies to avoid ambiguity in interpreting the weakening of bounds.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for their positive assessment of our manuscript and for recommending minor revision. The referee's summary accurately reflects our analysis of the non-leptonic B decay anomalies and the three directions explored to potentially relax collider bounds on additional SU(2)_L scalar doublets. We appreciate the credit given for the concrete LHC recasts, power-correction estimates, and multi-doublet scans. We will implement the minor revisions in the next version of the manuscript.

Circularity Check

0 steps flagged

No significant circularity detected

full rationale

The paper derives collider bounds on SU(2)_L doublet scalars from independent LHC searches (charged Higgs and ttbar recasts) that are not fitted to the B-decay anomaly data. Power-correction estimates and multi-doublet dilution scans use standard QCD and parameter-space methods without reducing to self-defined inputs or self-citation chains. No step equates a prediction to its own fitted parameter by construction, and external benchmarks remain independent of the present results.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 1 invented entities

Paper relies on standard model assumptions for baseline B decay rates and postulates additional scalar doublets as new physics; no free parameters or invented entities beyond conventional BSM scalars are detailed in the abstract.

axioms (1)
  • domain assumption Standard Model provides accurate baseline for non-leptonic B decay rates absent new physics
    Invoked when stating anomalies as deviations from SM predictions
invented entities (1)
  • additional SU(2)_L scalar doublets no independent evidence
    purpose: To mediate new physics explaining the B decay anomalies
    Postulated to explore viable models consistent with anomalies

pith-pipeline@v0.9.0 · 5524 in / 1215 out tokens · 49661 ms · 2026-05-07T15:51:56.956778+00:00 · methodology

discussion (0)

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Reference graph

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