REVIEW 3 major objections 7 minor 48 references
Charmless B→VV decays disagree with the SU(3)_F Standard Model by more than 7σ once ϕ and ω modes are included.
Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →
T0 review · grok-4.5
2026-07-30 11:07 UTC pith:YBJ5V26Y
load-bearing objection Clean, cross-checked SU(3) fits show a real exact-symmetry tension in B o VV (5.2–>7σ); the SM-anomaly reading still needs a breaking study. the 3 major comments →
Anomalies in Hadronic B to VV Decays
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
In the exact SU(3)_F limit of the Standard Model, a global fit of the effective topological diagrams to all available charmless B→VV data yields χ²_min/d.o.f. = 39.2/5 (5.2σ) when V ∈ {ρ, K*} and χ²_min/d.o.f. = 130/20 (>7σ) when V ∈ {ρ, K*, ϕ, ω}. The isospin-only B→ρK* subset remains acceptable (χ²_min/d.o.f. = 3.6/3).
What carries the argument
SU(3)_F reduced matrix elements (equivalently, effective topological diagrams) for each of the three transversity amplitudes, reduced by the electroweak-penguin–tree relations after dropping c7 and c8.
Load-bearing premise
That the roughly 30 percent SU(3) breaking expected in the Standard Model cannot absorb a tension larger than 7σ.
What would settle it
A global fit that allows O(30 %) SU(3)_F breaking among the same diagrams and still finds an acceptable χ² would falsify the claim that the discrepancy is anomalous.
If this is right
- Polarization fractions and CP asymmetries in the still-unmeasured B→VV modes become high-priority experimental targets.
- Any new-physics explanation proposed for the earlier B→PP anomaly must also accommodate the larger VV tension.
- Isospin sum rules for each transversity of B→ρK* can be tested once complete angular analyses of all four modes exist.
- The pattern of which observables dominate the χ² points to longitudinal-versus-transverse polarization mismatches between ΔS=0 and ΔS=1 channels.
Where Pith is reading between the lines
- If the same diagrams also fail once moderate SU(3) breaking is introduced, the anomaly would rank among the strongest indirect hints in the flavour sector.
- The growth of tension when ϕ and ω are added suggests that singlet–octet mixing or OZI-suppressed amplitudes may be the most sensitive probes.
- A parallel U-spin analysis restricted to the K*K* and ρρ pairs could isolate whether the breaking is mainly s↔d or more general.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper extends a previous exact-flavour-SU(3)_F analysis of charmless B→PP decays to B→VV, treating the three transversity amplitudes separately. It gives RME and topological-diagram decompositions for (8⊗8)S, 8⊗1 and 1⊗1 final states, imposes EWP–tree relations after neglecting c7,c8, and performs three fits. An isospin-only B→ρK* fit has χ²min/d.o.f.=3.6/3, although with unexpectedly large effective Puc/Ptc ratios. Requiring common SU(3)_F diagrams for V∈{ρ,K*} gives χ²min/d.o.f.=39.2/5, quoted as 5.2σ from SM_SU(3)_F; including ω and ϕ gives χ²min/d.o.f.=130/20, quoted as >7σ. The authors emphasize that these are exact-SU(3)_F results and that ∼30% symmetry breaking remains to be checked.
Significance. If the numerical fits are robust, this is a significant over-constrained test of flavour SU(3)_F in charmless B→VV decays and a useful companion to the reported B→PP tension. Notable strengths are the explicit RME and diagram decompositions in Tables III–VIII, the EWP–tree relations, the careful independent-observable counting in Appendix E, the experimental isospin sum-rule test, and the cross-checking of large fits with three independent codes and many starting points. The result is presently strongest as evidence against the exact symmetry limit; its interpretation as a Standard Model anomaly awaits quantified SU(3)-breaking and fitting systematics.
major comments (3)
- [§IV.B–C, Eqs. (31)–(41), Tables XV–XVI] The fits force each helicity’s effective diagrams/RMEs to be common across ΔS=0, ΔS=1 and related final states. Tables XV–XVI therefore establish a failure of the exact-SU(3)_F implementation, not yet of the full SM. No helicity- or channel-dependent SU(3)-breaking nuisance parameters or theory covariance enter the 5.2σ and >7σ significances; the abstract and §V instead rely on the unquantified judgement that ∼30% breaking is unlikely to suffice. Please scan or marginalize over a specified breaking model, or restrict the conclusions to exclusion of SM_SU(3)_F.
- [§IV and Appendices C and E] The χ² construction appears to treat all entries as independent Gaussian observables. Several fitted quantities come from the same angular analyses—for example the large sets for B+→ρ0K*+ in Table X, Bs→K*0 anti-K*0 in Table X, and Bs→ϕϕ in Table XII. Appendix E removes algebraic redundancy, but algebraic independence does not imply statistical or systematic uncorrelatedness. The experimental covariance matrices, or a conservative correlation sensitivity analysis, are needed before the precise χ² values and Gaussian-equivalent significances can be regarded as established.
- [Eqs. (21), (25), (32), (34), (38) and (41); §§IV–V] The EWP–tree relations neglect c7,c8, with an estimated ∼10% modification, but this uncertainty is not propagated into the fit. CKM inputs are also fixed to central world averages in §IV. Since these choices reduce the parameter space and the quoted discrepancies are 5–7σ, the fit should include nuisance variations or a demonstrated theory covariance, and report the resulting range of χ²min/significance.
minor comments (7)
- [§IV.C, Eq. (44)] Please state the numerical value and source used for θω, whether it is fixed or fitted, and how its uncertainty/convention is treated. Table XVI contains no θω entry, although the enlarged fit depends on the ω–ϕ decomposition.
- [Appendix C, Tables IX and XI] Several branching fractions are near or outside the physical boundary, e.g. B(B0→ϕϕ)=(-0.04±0.12)×10−6 and B(B0→ωϕ)=(0.0±0.3)×10−6. Explain the likelihood used for these and for asymmetric entries such as B(B0→K*+K*−), and show that excluding or treating them as upper-limit likelihoods does not materially change the result.
- [§I] The statement that fL=0.16 versus 0.61 directly indicates strong U-spin violation should be qualified. Exact U-spin relates these amplitudes with different CKM factors and tree/penguin compositions, so it does not by itself require equal fL values.
- [§III.A, Eqs. (27)–(30)] Give the normalization and units of δρK* in its numerical test. It is not clear from Eqs. (27)–(30) and the amplitude units why the result is quoted as (-4±6)×10−4.
- [Tables XIII–XVI] The phase notation such as “(36±23)×10°” is ambiguous, and several phases have errors comparable to or reach the imposed [0,360°] range. Please clarify the notation and treatment of phase boundaries.
- [§III.A and Table XII] Typographical/notation issues: “ampliudes” after Eq. (30), and the symbol rendered as fδ⊥ in Table XII should be checked against the phase notation of Eq. (13). The tangent transformation and associated error propagation should also be stated explicitly.
- [§V and Appendix D] Reproducibility would be substantially improved by providing machine-readable fit inputs, per-observable χ² contributions, and the minimization code or notebooks, particularly given the stated three-code cross-check.
Circularity Check
Standard overconstrained SU(3)_F fit: free diagrams vs external data; poor χ² is an output, not an input by construction.
full rationale
The paper parametrizes B→VV amplitudes via SU(3)_F (or isospin) reduced matrix elements / effective topological diagrams (Secs. III–IV, Eqs. 31–41, Tables III–VIII), imposes standard EWP–tree relations after neglecting c7,c8 (~10% theory input), fixes CKM elements to external world averages, and minimizes χ² against experimental branching ratios, polarization fractions, CP asymmetries, and phases (Tables IX–XII). The reported 5.2σ and >7σ discrepancies are the resulting fit qualities (χ²_min/d.o.f. = 39.2/5 and 130/20), not quantities forced by the definitions of the free parameters. Effective diagrams are linear redefinitions of RMEs (Eqs. 36–41), an equivalent basis, not a tautology that manufactures tension. Self-citations to the authors’ B→PP and B→πK papers supply the shared methodology and EWP–tree relations; they do not supply the VV data or the χ² values. No fitted subset is relabeled a prediction, no uniqueness theorem is load-bearing, and no sum rule or polarization observable is defined in terms of the claimed anomaly. The analysis is self-contained against external benchmarks; any concern about unmodeled SU(3)_F breaking is a correctness/interpretation issue, not circularity.
Axiom & Free-Parameter Ledger
free parameters (5)
- B→ρK* isospin diagram set (12 magnitudes + 11 relative strong phases) =
χ²_min=3.6/3 unconstrained; 26.1/3 with |P̃_uc/P̃_tc|≤1
- SU(3) (8⊗8)_S diagram set for V∈{ρ,K*} (21 magnitudes + 20 relative strong phases) =
χ²_min/d.o.f.=39.2/5
- Full SU(3) diagram set including 8⊗1 and 1⊗1 (39 magnitudes + 38 relative strong phases) =
χ²_min/d.o.f.=130/20
- CKM magnitudes and weak phases β, γ, β_s =
world averages [35]
- ω–ϕ mixing angle θ_ω =
arctan(1/√2)≈35.3°
axioms (6)
- domain assumption Exact flavour SU(3)_F (or exact isospin) relates all amplitudes via a common set of RMEs/effective diagrams for each helicity.
- domain assumption EWP–tree relations after neglecting Wilson coefficients c7 and c8 (expected ~10% correction if restored).
- standard math Wigner–Eckart / topological-diagram equivalence: only effective linear combinations of diagrams appear, matching the RME count.
- domain assumption Naive size estimates |P_uc/P_tc|<0.5 (or conservative ≤1) and |E,A|/T≲5% may be used as optional constraints but are not required for the headline χ².
- domain assumption Experimental averages from HFLAV/PDG and primary papers are treated as independent Gaussian (or asymmetric) inputs after the observable-counting reductions of Appendix E.
- ad hoc to paper ~30% SU(3)_F breaking is unlikely to remove a >7σ symmetry-limit discrepancy.
read the original abstract
Recently, a fit of charmless $B\to PP$ decays ($B \in \{B^0, B^+, B_s^0\}$, $P \in \{ \pi, K, \eta, \eta' \}$) to the latest data was performed under the assumption of flavour SU(3) symmetry [SU(3)$_F$]. It was found that there is a $4.1\sigma$ disagreement with the SU(3)$_F$ limit of the Standard Model [$\rm SM_{SU(3)_F}$]. In this paper, we extend this analysis to charmless $B \to VV$ decays ($V \in \{\rho, K^*, \phi, \omega\}$). The fit examining $B \to \rho K^*$ decays, assuming only isospin symmetry, is found to be acceptable. When we fit to $B \to VV$ decays with $V \in \{ \rho, K^* \}$ within SU(3)$_F$, we find a $5.2\sigma$ discrepancy with SM$_{SU(3)_F}$. Finally, when $B \to VV$ decays with $V \in \{ \rho, K^*, \phi, \omega \}$ are considered, the discrepancy grows to $>7\sigma$. The theoretical input in this analysis is modest, so our results are quite rigorous, group theoretically, and hold almost exactly in the SU(3)$_F$ limit. Although it seems unlikely that the introduction of $\sim 30$% SU(3)$_F$-breaking effects can account for this discrepancy, this must be verified.
Figures
Reference graph
Works this paper leans on
-
[1]
The quarks (u, d, s) form a triplet (3) under SU(3)F , so that the initial stateB= (B +, B0, B0 s ) also is a3
RMEs We begin with the (8⊗8) S final state. The quarks (u, d, s) form a triplet (3) under SU(3)F , so that the initial stateB= (B +, B0, B0 s ) also is a3. The weak Hamiltonian 14 (8⊗8) S ∆S= 0 ∆S= 1 B+ →K ∗+ ¯K∗0 B+ →ρ +K∗0 B+ →ρ +ρ0 B+ →ρ 0K∗+ B+ →ω 8 ρ+ B+ →ω 8 K∗+ B0 →K ∗0 ¯K∗0 B0 s →K ∗0 ¯K∗0 B0 →ρ +ρ− B0 s →ρ +ρ− B0 →ρ 0ρ0 B0 s →ρ 0ρ0 B0 →K ∗+K∗− B0...
-
[2]
There are six diagrams proportional toλ (q) u :T,C,P uc,E,A,P A uc
Diagrams The amplitudes can also be expressed in terms of diagrams. There are six diagrams proportional toλ (q) u :T,C,P uc,E,A,P A uc. There are eight diagrams proportional toλ (q) t : Ptc,P Atc,P EW ,P C EW ,P A EW ,P E EW ,P Pu EW ,P P Au EW . For the (8⊗8) S final state, Ref. [2] gives the expressions for theB→P Pamplitudes in terms of diagrams. As us...
-
[3]
R. Berthiaume, B. Bhattacharya, R. Boumris, A. Jean, S. Kumbhakar, and D. London, Phys. Rev. Lett.133, 211802 (2024), arXiv:2311.18011 [hep-ph]
Pith/arXiv arXiv 2024
-
[4]
B. Bhattacharya, M. Bouchard, L. Hudy, A. Jean, D. London, and C. MacKenzie, (2025), arXiv:2505.11492 [hep-ph]
arXiv 2025
-
[5]
D. Choudhury, S. Kumbhakar, A. Kundu, and S. Nandi, Phys. Rev. D114, 015019 (2026), arXiv:2601.05324 [hep-ph]
Pith/arXiv arXiv 2026
-
[6]
J. Chai, S. Cheng, F.-Q. Hu, Y. Li, J.-Y. Shen, and D.-C. Yan, (2026), arXiv:2607.22093 [hep-ph]. 37
Pith/arXiv arXiv 2026
-
[7]
Banerjeeet al.(Heavy Flavor Averaging Group (HFLA V)), Phys
S. Banerjeeet al.(Heavy Flavor Averaging Group (HFLA V)), Phys. Rev.D113, 012008 (2026), with online updates athttps://hflav.web.cern.ch/, arXiv:2411.18639 [hep-ex]
Pith/arXiv arXiv 2026
-
[8]
M. Alguer´ o, A. Crivellin, S. Descotes-Genon, J. Matias, and M. Novoa-Brunet, JHEP04, 066, arXiv:2011.07867 [hep-ph]
Pith/arXiv arXiv 2011
- [9]
-
[10]
M. Beneke, J. Rohrer, and D. Yang, Nucl. Phys. B774, 64 (2007), arXiv:hep-ph/0612290
Pith/arXiv arXiv 2007
-
[11]
A. S. Dighe, I. Dunietz, H. J. Lipkin, and J. L. Rosner, Phys. Lett. B369, 144 (1996), arXiv:hep-ph/9511363
Pith/arXiv arXiv 1996
-
[12]
R. Fleischer and I. Dunietz, Phys. Rev. D55, 259 (1997), arXiv:hep-ph/9605220
Pith/arXiv arXiv 1997
-
[13]
A. S. Dighe, I. Dunietz, and R. Fleischer, Eur. Phys. J. C6, 647 (1999), arXiv:hep-ph/9804253
Pith/arXiv arXiv 1999
-
[14]
C.-W. Chiang and L. Wolfenstein, Phys. Rev. D61, 074031 (2000), arXiv:hep-ph/9911338
Pith/arXiv arXiv 2000
-
[15]
B. Bhattacharya, A. Datta, M. Duraisamy, and D. London, Phys. Rev. D88, 016007 (2013), arXiv:1306.1911 [hep-ph]
Pith/arXiv arXiv 2013
-
[16]
R. Aaijet al.(LHCb), Phys. Rev. Lett.136, 021803 (2026), arXiv:2508.13563 [hep-ex]
Pith/arXiv arXiv 2026
-
[17]
Aaijet al.(LHCb), JHEP12, 155, arXiv:1907.10003 [hep-ex]
R. Aaijet al.(LHCb), JHEP12, 155, arXiv:1907.10003 [hep-ex]
arXiv 1907
-
[18]
A. Datta and D. London, Int. J. Mod. Phys. A19, 2505 (2004), arXiv:hep-ph/0303159
Pith/arXiv arXiv 2004
-
[19]
Aaijet al.(LHCb), JHEP05, 026, arXiv:1812.07008 [hep-ex]
R. Aaijet al.(LHCb), JHEP05, 026, arXiv:1812.07008 [hep-ex]
-
[20]
G. Buchalla, A. J. Buras, and M. E. Lautenbacher, Rev. Mod. Phys.68, 1125 (1996), arXiv:hep-ph/9512380
Pith/arXiv arXiv 1996
-
[21]
Chau and H.-Y
L.-L. Chau and H.-Y. Cheng, Phys. Rev. Lett.56, 1655 (1986)
1986
-
[22]
M. Gronau, O. F. Hernandez, D. London, and J. L. Rosner, Phys. Rev. D50, 4529 (1994), arXiv:hep-ph/9404283
Pith/arXiv arXiv 1994
-
[23]
M. Gronau, O. F. Hernandez, D. London, and J. L. Rosner, Phys. Rev. D52, 6374 (1995), arXiv:hep-ph/9504327
Pith/arXiv arXiv 1995
-
[24]
M. Gronau, D. Pirjol, and T.-M. Yan, Phys. Rev. D60, 034021 (1999), [Erratum: Phys.Rev.D 69, 119901 (2004)], arXiv:hep-ph/9810482
Pith/arXiv arXiv 1999
-
[25]
A. J. Buras and R. Fleischer, Phys. Lett. B341, 379 (1995), arXiv:hep-ph/9409244
Pith/arXiv arXiv 1995
-
[26]
M. Beneke, G. Buchalla, M. Neubert, and C. T. Sachrajda, Nucl. Phys. B606, 245 (2001), arXiv:hep-ph/0104110
Pith/arXiv arXiv 2001
- [27]
-
[28]
G. Bell, Nucl. Phys. B822, 172 (2009), arXiv:0902.1915 [hep-ph]. 38
Pith/arXiv arXiv 2009
-
[29]
M. Beneke, T. Huber, and X.-Q. Li, Nucl. Phys. B832, 109 (2010), arXiv:0911.3655 [hep-ph]
Pith/arXiv arXiv 2010
-
[30]
G. Bell, M. Beneke, T. Huber, and X.-Q. Li, Phys. Lett. B750, 348 (2015), arXiv:1507.03700 [hep-ph]
Pith/arXiv arXiv 2015
-
[31]
A. J. Buras, R. Fleischer, S. Recksiegel, and F. Schwab, Eur. Phys. J. C32, 45 (2003), arXiv:hep-ph/0309012
Pith/arXiv arXiv 2003
-
[32]
A. J. Buras, R. Fleischer, S. Recksiegel, and F. Schwab, Phys. Rev. Lett.92, 101804 (2004), arXiv:hep-ph/0312259
Pith/arXiv arXiv 2004
-
[33]
A. J. Buras, R. Fleischer, S. Recksiegel, and F. Schwab, Nucl. Phys. B697, 133 (2004), arXiv:hep-ph/0402112
Pith/arXiv arXiv 2004
-
[34]
B. Bhattacharya, M. Bouchard, A. Jean, D. London, and I. Ray, JHEP05, 195, arXiv:2510.13969 [hep-ph]
- [35]
-
[36]
I. Adachiet al.(Belle-II), Phys. Rev. D109, 012001 (2024), arXiv:2310.06381 [hep-ex]
Pith/arXiv arXiv 2024
-
[37]
Takahashiet al.(Particle Data Group), Int
F. Takahashiet al.(Particle Data Group), Int. J. Mod. Phys. A41, 2630011 (2026)
2026
-
[38]
James and M
F. James and M. Roos, Comput. Phys. Commun.10, 343 (1975)
1975
-
[39]
B. Aubertet al.(BaBar), Phys. Rev. D78, 051103 (2008), arXiv:0806.4467 [hep-ex]
Pith/arXiv arXiv 2008
-
[40]
B. Aubertet al.(BaBar), Phys. Rev. D78, 071104 (2008), arXiv:0807.4977 [hep-ex]
Pith/arXiv arXiv 2008
-
[41]
Aaijet al.(LHCb), (2025), arXiv:2512.05102 [hep-ex]
R. Aaijet al.(LHCb), (2025), arXiv:2512.05102 [hep-ex]
Pith/arXiv arXiv 2025
-
[42]
del Amo Sanchezet al.(BaBar), Phys
P. del Amo Sanchezet al.(BaBar), Phys. Rev. D83, 051101 (2011), arXiv:1012.4044 [hep-ex]
Pith/arXiv arXiv 2011
-
[43]
B. Aubertet al.(BaBar), Phys. Rev. Lett.101, 201801 (2008), arXiv:0807.3935 [hep-ex]
Pith/arXiv arXiv 2008
-
[44]
B. Aubertet al.(BaBar), Phys. Rev. D79, 052005 (2009), arXiv:0901.3703 [hep-ex]
Pith/arXiv arXiv 2009
-
[45]
J. P. Leeset al.(BaBar), Phys. Rev. D89, 051101 (2014), arXiv:1312.0056 [hep-ex]
Pith/arXiv arXiv 2014
-
[46]
Y. Guanet al.(Belle), Phys. Rev. Lett.133, 081801 (2024), arXiv:2401.04646 [hep-ex]
Pith/arXiv arXiv 2024
-
[47]
Aaijet al.(LHCb), JHEP05, 069, arXiv:1403.2888 [hep-ex]
R. Aaijet al.(LHCb), JHEP05, 069, arXiv:1403.2888 [hep-ex]
-
[48]
R. Aaijet al.(LHCb), Phys. Rev. Lett.131, 171802 (2023), arXiv:2304.06198 [hep-ex]. 39
arXiv 2023
discussion (0)
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