Improved Calculation of Electroweak Radiative Corrections and the Value of V_ud

Alberto Sirlin; William J. Marciano

REVIEW

Improved Calculation of Electroweak Radiative Corrections and the Value of V_ud

William J. Marciano, Alberto Sirlin

High Energy Physics - Phenomenology · Submitted 7 Oct 2005 · 22 references

Pith's verdict: The method is the real contribution; the factor-of-two error reduction is a hand-assigned percentage on the region-2 interpolator, and the details are deferred to a paper not yet written.

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arXiv IDhep-ph/0510099 (version 2)

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CitationAlberto Sirlin, William J. Marciano. "Improved Calculation of Electroweak Radiative Corrections and the Value of V_ud." arXiv:hep-ph/0510099 (2005). https://pith.science/paper/NEC4P7EO

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Editor's note

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Short version: the method is the news, not the number. The central value moves by +0.00007, well inside the old error bar, so what Marciano and Sirlin are really selling is the reduction of the hadronic loop uncertainty from ±0.0004 to ±0.00019 in V_ud. That claim is stated candidly but is thinner than the abstract makes it sound. What holds up: the short-distance piece is not hand-waving. The O(alpha_s^3) coefficients in eqs. (9)-(11) come from the Bjorken sum rule literature and have been tested against polarized scattering data [16], which is genuine external support rather than self-citation. The three-resonance interpolator in eq. (12) satisfies the two conditions you can check by hand, the vanishing 1/Q^4 coefficient and F(0)=0, so the construction is internally consistent. The near-zero shift in the central value is itself a useful check: the old OPE-plus-cutoff estimate was not badly wrong. Where it is soft: do the arithmetic on the error budget after eq. (16). ±10% on C_Born gives about 0.00019 in RC, ±0.0001 is assigned to higher orders, and the quoted total is ±0.00038, so roughly 0.00031, nearly all the remaining budget, is the ±100% assigned to the region-2 interpolator integral. The headline improvement is, numerically, the assertion that that integral is known to a factor of two. The paper never quotes the integral or argues for 100% over 50% or 200%; at 200% the gain over the old ±0.0004 largely evaporates. The authors call the assignment heuristic, which is candid, but it is also the entire content of the improvement claim. Two smaller points. C_Born = 0.829 is computed for the neutron, while the V_ud average comes from nuclei, where the paper itself notes quenching and nucleon-nucleon electromagnetic effects modify it; the ±10% is not shown to cover that. And the residues, the matching procedure, and the C_Born update all live in ref. [12], described as a longer manuscript to come, so nothing load-bearing here is independently checkable yet. None of this undermines the result, and the unitarity reordering, with the dominant error now in f+(0), is real. Read it as a progress report with a promised follow-up rather than a finished error budget. Worth refereeing; I would cite it for the method and the V_ud value, with the caveat that the ±0.0002 waits on [12].

Referee report

Significance

If the error budget holds, this is the state-of-the-art treatment of the dominant hadronic uncertainty in low-energy semileptonic charged-current processes, and the unitarity test at the ±0.09% level is a meaningful Standard Model check. The central value is a validation of the authors' 1986 result, and the method is anchored to the experimentally verified Bjorken sum rule [16]; I checked that the coefficients in Eqs. (10)-(11) reproduce the standard N_F=3 values (C2 ≈ 3.58, C3 ≈ 20.2), and that Eq. (12) satisfies the stated chiral constraints (F(0) ≈ 0, vanishing 1/Q⁴ coefficient). Eq. (17) is a falsifiable prediction for future τ_n and g_A measurements. The improvement claim, however, is a judgment-based error assignment rather than a derived one, and that is where this report concentrates.

Major objections (3)

[Paragraph following Eq. (16)] The headline claim — a factor-of-2 reduction of the loop uncertainty — is arithmetically the assignment of ±100% to the region-2 interpolator integral over (0.823 GeV)² ≤ Q² < (1.5 GeV)². Decomposing the quoted ±0.00038 in RC: ±10% of the C_Born term contributes ≈0.00019, ±0.0001 is assigned to higher orders, and the remainder ≈0.00031 must come from region 2. The letter never quotes the size of that integral, never shows the matching point at which Eq. (12) equals the long-distance integrand, and gives no argument for 100% rather than 50% or 200%. At 200% the total becomes ≈0.00066 in RC (≈0.00033 in V_ud), and the improvement over the old ±0.0004 largely disappears. Since the fixed-point condition defining the (0.823 GeV)² boundary is itself part of what the 100% is meant to cover, the letter should at minimum quote the region-2 integral, state the matching point, and justify the percentage.
[Eqs. (12) and (16)] The residues of the interpolator in Eq. (12), the matching procedure that fixes them, and the updated C_Born = 0.829 in Eq. (16) are all deferred to ref. [12], described in the text as 'a later, longer manuscript' — i.e., unpublished. A letter may defer details, but the central quantitative inputs of the method should be reproducible from the letter itself. At minimum the manuscript should list the three residues, state the matching point Q², and give the value of the region-2 integral, so that a reader can check the arithmetic of the error budget in the preceding comment without access to ref. [12].
[Eq. (16) and the superallowed analysis] C_Born = 0.829 in Eq. (16) is computed for the neutron, but the V_ud average in Eq. (19) and Table 2 is from nuclei. The text itself notes (paragraph after Eq. (8)) that 'nuclear quenching modifies C_Born(neutron) and nucleon-nucleon electromagnetic effects must be included [11]', yet the ±10% assigned to C_Born in the error budget is not shown to cover those nuclear modifications. The manuscript should either quote the nuclear value of C_Born used in the superallowed analysis or argue explicitly that the ±10% envelope covers the quenching and nucleon-nucleon electromagnetic corrections.

Minor objections (7)

[Eq. (17)] The definition 'gA ≡ GV/GA' is inverted; it should read G_A/G_V, consistent with Eq. (8) where g_A ≃ 1.27.
[Table 2, first column] The entry '140' should be '14O'.
[Table 2, weighted average] The quoted uncertainty 0.00011 is the unscaled inverse-variance error; with the nine entries of Table 2 the χ²/dof is ≈1.9, driven by 46V at 2.7σ, so a scale factor of ≈1.4 would give ≈0.00015. Because the total is dominated by the (15) and (19) entries, the conclusion is unaffected, but the number should be corrected or a scale factor noted.
[Eq. (21)] The (5) attached to V_ud is the quadrature sum of (11)(15)(19); this should be stated explicitly so the reader can verify the propagation.
[Paragraph following Eq. (16)] The text states that the last three terms of Eq. (4) are replaced by 2.82 α/π and that the correction is reduced by 1.4×10⁻⁴. Since Eq. (4) is normalized by α/2π, 2.82 α/π = 5.64 α/2π, and the comparison with the old bracket (≈5.77) is consistent; but the factor-of-2 change of normalization is easy to miss and should be stated explicitly.
[Eq. (7) versus Eq. (4)] Eq. (7) is normalized by α/4π while Eq. (4) is normalized by α/2π; the factor of 2 (amplitude versus rate) should be stated to avoid the appearance of an inconsistency.
[Reference [12]] A preprint number should be supplied for ref. [12] if one exists, since the central quantitative inputs of the letter depend on it.

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The paper

The paper claims

A three-region treatment of the photon–W box diagram halves the hadronic uncertainty in the extraction of the CKM element $V_{ud}$ from superallowed nuclear beta decay, leaving the CKM unitarity sum at $0.9992$.

The reading

Superallowed $0^+$ nuclear $\beta$ decays give the cleanest handle on $V_{ud}$, the largest CKM matrix element, because the weak vector current is protected at tree level by conserved-vector-current symmetry. The catch is that the electroweak radiative correction one must divide out contains a piece induced by the axial-vector current — the $gammaleftrightarrow W$ box diagram — that strong interactions make hard to compute. Marciano and Sirlin split the box integral into three momentum regimes and treat each with the best available tool: order-$alpha_s^3$ perturbative QCD coefficients borrowed from the Bjorken sum rule at short distances, a three-resonance interpolating function motivated by large-$N_c$ QCD at intermediate distances, and updated nucleon dipole form factors at long distances. Matching the three regimes reduces the axial-vector-induced correction slightly and, more to the point, cuts the assigned hadronic loop uncertainty from about $0.0004$ to $0.0002$ in $V_{ud}$. The payoff is a sharper unitarity test: if the new error budget holds, the Standard Model's charged-current sector closes to better than a part in a thousand, and the dominant theoretical error in that test moves from the loop corrections to the $K_{l3}$ form factor $f_+(0)$.

What carries the argument

The load-bearing object is the interpolating function of eq. (12), $F(Q^2) = -1.490/(Q^2+m_ho^2) + 6.855/(Q^2+m_A^2) - 4.414/(Q^2+m_{ho'}^2)$, with $m_ho = 0.776~mathrm{GeV}$, $m_A = 1.230~mathrm{GeV}$ and $m_{ho'} = 1.465~mathrm{GeV}$. Its three residues are not fitted to data but fixed by three structural requirements: the integral over the intermediate region must match the asymptotic QCD integral over $(1.5~mathrm{GeV})^2 leq Q^2 < infty$; the coefficient of $1/Q^4$ in its large-$Q^2$ expansion must vanish, as chiral symmetry demands; and the function must vanish at $Q^2=0$, as chiral perturbation theory requires. Those three conditions exhaust three resonances, which is why the sum stops at three. The lower matching point $Q^2 = (0.823~mathrm{GeV})^2$ is not imposed but found: it is where the interpolator equals the long-distance integrand, and it lands near the $ho$ mass. A second piece of machinery is a technical ordering choice — in the long-distance Feynman diagrams the auxiliary Feynman parameters are integrated first, so the result is an integrand in $Q^2$ that can be matched onto eq. (12) at all.

Extended reading notes

Core claim

The paper's claim is that the hadronic uncertainty in the electroweak radiative corrections to low-energy semileptonic processes can be brought under control by a matched three-region description of the axial-vector-induced $gammaleftrightarrow W$ box amplitude $F(Q^2)$. Above $Q^2=(1.5~mathrm{GeV})^2$ the authors use the operator-product form with QCD corrections carried to order $alpha_s^3$, with coefficients $C_2 = 4.583 - 0.333N_F$ and $C_3 = 41.440 - 7.607N_F + 0.177N_F^2$ taken over from the Bjorken sum rule. Between $(0.823~mathrm{GeV})^2$ and $(1.5~mathrm{GeV})^2$ they use a three-pole interpolator in $ho$, $A_1$ and $ho'$ with residues fixed by three conditions. Below $(0.823~mathrm{GeV})^2$ they integrate the long-distance amplitude directly with updated nucleon electromagnetic and axial dipole form factors, obtaining $C_{mathrm{Born}}(mathrm{neutron}) simeq 0.829$ in place of the earlier $0.89$. The net effect is that the last three terms of the one-loop correction are replaced by $2.82,alpha/pi$ for neutron decay, a reduction of $1.4times10^{-4}$ in the correction and a $+7times10^{-5}$ shift upward in $V_{ud}$ — a validation of the authors' 1986 result rather than a revision of it. With the loop error taken as $pm0.00038$ in the correction, the weighted average over nine superallowed decays becomes $V_{ud} = 0.97377(11)(15)(19)$, and combining with the $K_{l3}$ value $V_{us} = 0.2257(9)(0.961/f_+(0))$ gives $|V_{ud}|^2+|V_{us}|^2+|V_{ub}|^2 = 0.9992(5)(4)(8)$.

Load-bearing premise

The claimed factor-of-two reduction in the loop uncertainty rests on error bands the authors assign by hand rather than derive: $pm10%$ on the long-distance $C_{mathrm{Born}}$ value, $pm100%$ on the interpolator's contribution over $(0.823~mathrm{GeV})^2 leq Q^2 < (1.5~mathrm{GeV})^2$, and $pm0.0001$ for neglected higher orders.

Editorial extensions

If this is right

The unitarity test $|V_{ud}|^2+|V_{us}|^2+|V_{ub}|^2 = 0.9992(5)(4)(8)$ stands as a quantum-loop-level check of the Standard Model and constrains new physics at the $pm0.09%$ level.
Because the loop error is now comparable to or below the $f_+(0)$ error, further progress on unitarity requires a better determination of the $K_{l3}$ form factor rather than better QCD loop calculations.
The neutron route, $|V_{ud}|^2 = 4908.7(1.9),mathrm{sec}, au_n(1+3g_A^2)$, becomes the eventual best determination of $V_{ud}$ once neutron lifetime and $g_A$ measurements improve.
The method is presented as general and reusable for other low-energy charged- and neutral-current semileptonic processes where axial-vector loop effects carry hadronic uncertainty.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

The same three-region matching could in principle be applied to the axial-vector box in parity-violating electron scattering and in neutral-current neutrino scattering, where the analogous hadronic uncertainty is currently a limiting error; the paper says the method is general but does not work those cases out.
The $2.7sigma$ low value of $V_{ud}$ from $^{46}mathrm{V}$, which the authors flag as following a $Q$-value revision, is a concrete handle: if further $Q$-value remeasurements move the other eight nuclei in the same direction, the central $V_{ud}$ drops and the apparent unitarity agreement in eq. (21) weakens without any change to the loop calculation.
Independent lattice determinations of the $gammaleftrightarrow W$ box hadronic contribution at low $Q^2$ would supply exactly the calibration that the hand-assigned $pm10%$ and $pm100%$ error bands lack, and could either confirm or inflate the claimed factor-of-two improvement.

Original abstract

A new method for computing hadronic effects on electroweak radiative corrections to low-energy weak interaction semileptonic processes is described. It employs high order perturbative QCD results originally derived for the Bjorken sum rule along with a large N QCD-motivated interpolating function that matches long and short-distance loop contributions. Applying this approach to the extraction of the CKM matrix element V_ud from superallowed nuclear beta decays reduces the theoretical loop uncertainty by about a factor of 2 and gives V_ud = 0.97377(11)(15)(19). Implications for CKM unitarity are briefly discussed.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 3,670 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.06 · states limitation 0.25 · human participants 0.02 · controlled comparison 0.05 · randomized assignment 0.01 · states quantitative result 0.99 · compares with prior results 0.62 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v2. Results and the main claim are underlined; show every role.

A new method for computing hadronic effects on electroweak radiative corrections to low-energy weak interaction semileptonic processes is described. It employs high order perturbative QCD results originally derived for the Bjorken sum rule along with a large N QCD-motivated interpolating function that matches long and short-distance loop contributions. Applying this approach to the extraction of the CKM matrix element V_ud from superallowed nuclear beta decays reduces the theoretical loop uncertainty by about a factor of 2 and gives V_ud = 0.97377(11)(15)(19). Implications for CKM unitarity are briefly discussed.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	A new method for computing hadronic effects on electroweak radiative corrections to low-energy weak interaction semileptonic processes is described.	contribution 0.85	0.84	0.07	asserted 0.95
s1	It employs high order perturbative QCD results originally derived for the Bjorken sum rule along with a large N QCD-motivated interpolating function that matches long and short-distance loop contributions.	method 0.99	0.36	0.04	asserted 1.00
s2	Applying this approach to the extraction of the CKM matrix element V_ud from superallowed nuclear beta decays reduces the theoretical loop uncertainty by about a factor of 2 and gives V_ud = 0.97377(11)(15)(19).	result 1.00	0.94	0.88	asserted 1.00
s3	Implications for CKM unitarity are briefly discussed.	interpretation 1.00	0.45	0.03	unclear 0.90

What kind of paper the classifier reports this is: method or tool 0.98 · evidence from simulation or computation 0.57.

What was examined, and what was not

sources read

arXiv listing abstract v2

not examined

full text
figures and tables
references and citing sentences
relations to other papers

levels run

P abstract

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S sections
T body sentences
C citations
R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

References

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First-Generation New Physics in Simplified Models: From Low-Energy Parity Violation to the LHC
hep-ph 2021-07 accept novelty 5.0 of 10

A unified SMEFT-based comparison of leptoquarks, vector bosons, vector-like quarks, and vector-like leptons against parity-violation, beta-decay, electroweak, and LHC data shows which models can still explain the Cabi...
Are the CKM anomalies induced by vector-like quarks? Limits from flavor changing and Standard Model precision tests
hep-ph 2021-03 conditional novelty 5.0 of 10

Existing flavor-changing and Z-pole data leave only narrow parameter windows for TeV-scale vector-like quarks as an explanation of the CKM first-row unitarity anomaly, and no single extra multiplet suffices.
The Fermi constant from muon decay versus electroweak fits and CKM unitarity
hep-ph 2021-02 accept novelty 5.0 of 10

The Fermi constant from muon decay, from a global electroweak fit, and from CKM unitarity disagree at 2 to 3.4 sigma, and a dimension-6 SMEFT survey leaves only two operator classes able to reconcile them.
New Physics effects in leptonic and semileptonic decays
hep-ph 2020-12 accept novelty 5.0 of 10

A general effective-Lagrangian fit to leptonic and semileptonic pseudoscalar-meson decays constrains scalar, tensor, vector and axial New Physics couplings and predicts three angular observables that can test them.
Muon $g-2$ and CKM Unitarity in Extra Lepton Models
hep-ph 2020-05 conditional novelty 5.0 of 10

A TeV-scale vectorlike lepton model with an SU(2) triplet and doublets can simultaneously relieve the muon g-2 and first-row CKM unitarity tensions, at the cost of a modified h to mu mu rate.
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hep-ph 2020-03 conditional novelty 5.0 of 10

Converting a lattice pion calculation to the neutron via Regge factorization yields a new value of the universal radiative correction, 0.02477(24), consistent with the earlier dispersion result and preserving the CKM ...
On the Statistical Treatment of the Cabibbo Angle Anomaly
hep-ph 2019-11 accept novelty 5.0 of 10

Testing Cabibbo angle universality across kaon and nuclear beta decays is a stronger Standard Model test than CKM first-row unitarity, and with current data the two give different significances (5.1 vs 4.8 sigma, or 3...
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hep-ph 2019-07 conditional novelty 5.0 of 10

The universal radiative correction to neutron and super-allowed nuclear beta decay is 2.426(32) percent, about 1.1 sigma below a 2018 dispersion-relation value and roughly midway between it and the 2006 result.
The CKM unitarity problem: A trace of new physics at the TeV scale?
hep-ph 2019-06 conditional novelty 5.0 of 10

Updated Vus and Vud determinations put the first row of the CKM matrix more than 4 sigma away from unitarity, and two TeV-scale scenarios are proposed to restore it.
$|V_{us}|$ from $K_{\ell 3}$ decay and four-flavor lattice QCD
hep-lat 2018-09 conditional novelty 5.0 of 10

Lattice QCD now gives the K to pi lepton-neutrino form factor f+(0) = 0.9696(19), hence |Vus| = 0.22333(61) with theory and experimental errors equal for the first time, and a 2 to 2.6 sigma tension with first-row CKM...
Nucleon Axial Radius and Muonic Hydrogen - A New Analysis and Review
hep-ph 2017-08 conditional novelty 5.0 of 10

Muonic hydrogen capture plus neutrino-scattering constraints give a nucleon axial radius of 0.46(16) fm^2 and confirm the chiral prediction for the induced pseudoscalar coupling at the 8% level.
PRyMordial: The First Three Minutes, Within and Beyond the Standard Model
hep-ph 2023-07 conditional novelty 4.0 of 10

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New UTfit Analysis of the Unitarity Triangle in the Cabibbo-Kobayashi-Maskawa scheme
hep-ph 2022-12 conditional novelty 4.0 of 10

An updated global Standard Model fit of the CKM unitarity triangle finds percent-level consistency with data, includes epsilon'/epsilon for the first time, and confirms a preference for large |Vcb| and small |Vub|.
Neutron Lifetime and Axial Coupling Connection
hep-ph 2018-02 accept novelty 4.0 of 10

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Electroweak Transitions of Hyperons and Charmed Baryons: Opportunities and Prospects
hep-ph 2026-10 conditional novelty 3.0 of 10

Baryon semileptonic decays of strange and charmed baryons are charted as a clean window to |V_us| and scalar/tensor new-physics searches, with concrete near-term precision targets.
FLAG Review 2021
hep-lat 2021-11 accept novelty 3.0 of 10

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FLAG Review 2024
hep-lat 2024-11 accept novelty 2.0 of 10

The FLAG 2024 review provides updated averages of lattice QCD determinations for quark masses, decay constants, form factors, mixing parameters, and nucleon matrix elements.
Anomalies in Particle Physics
hep-ph 2023-09 conditional novelty 2.0 of 10

A survey of particle-physics anomalies finds that new Higgs bosons and leptoquarks are the most promising explanations, though the evidence is heterogeneous and not yet conclusive.
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hep-lat 2019-04 conditional novelty 2.0 of 10

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hep-ph 2013-03 accept novelty 2.0 of 10

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hep-ph 2006-03 unverdicted

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How later papers used it

79 later papers cite it

Evidence: substantial. 77 of the citing papers share no author with it, and 21 of those carry a confident label from Pith's citation classifier.

Pith read 17 of the 134 citing sentences, choosing only those whose citation markers point at this paper alone, and wrote the paraphrases from them. The summary, the counts, the evidence level, the links and the quotes come from code; the summary counts the papers listed below. A later paper is listed under a label when Pith's citation classifier gives one of its sentences that label at probability 0.8 or more (0.95 for support), Pith's reading finds that the citing paper itself did it, and a second check confirms the paraphrase against the sentence. This section lists uses only. It does not list criticism or disagreement, so their absence here says nothing about how the paper has been received. Papers that share an author with this one are listed apart, under "By the same authors". A quote is the citing authors' own sentence, shown when their paper's licence is CC BY, CC BY-SA or CC0. JSON

2 later papers by other authors are listed below: 2 used its data or values.

Uses its data or values 2 of 18 papers with this label

Included a ±1×10^-4 uncertainty following this paper.

The Standard Model theory of neutron beta decay (2023) · 0.90 · paraphrased: the licence does not allow quoting
Took its value for the quantity determined from nuclear 0+ to 0+ transitions from this paper.

Tests of non-standard electroweak couplings of right-handed quarks (2007) · 0.94 · paraphrased: the licence does not allow quoting

How the literature uses it

52 arXiv papers cite this in 80 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 54 sentences without a confident label

Contests it 1 paper

Ref. [ref] fixed these four parameters with the four criteria as follows (we will see later than some of them are invalidated by more recent studies): * The result of the integral [ref] at $Q^2>(1.5 GeV)^2$ is required to be the same using the VMD parameterization and the asymptotic expression. * In the large-$Q^2$ limit, the coefficient of the $1/Q^4$ term in Eq.[ref] is required to vanish by chiral symmetry. * Eq.[ref] is required to vanish at $Q^2=0$ by ChPT. * Finally, the connection scale $Q_1^2$ is chosen through the matching of $F_Born$ and $F_Interpolation$ at $Q^2=Q_1^2$.

Radiative corrections to semileptonic beta decays: Progress and challenges · Earlier attempts · contest 0.79

Uses its data or values 12 papers

Results and conclusion: According to the PDG [ref] , precise values of $|V_ud|^2$ are obtained from superallowed nuclear and neutron beta decays [ref] as [equation] For superallowed decays, the first uncertainty stems from analyzing the half-lives of 15 precisely measured decays [ref] .

Lattice QCD Calculation of Electroweak Box Contributions to Superallowed Nuclear and Neutron Beta Decays · Introduction · 0.97
We take values from Refs. [ref] for the vector coupling constant $g_V(μ_χ= m_e) = 1.02499(13)$.

Radiative corrections to inverse beta decay: a precision analysis for reactor neutrinos · Inverse beta decay · 1.00
In this work, we adopt the vector coupling constant at the electron-mass renormalization scale $g_V = 1.02499(13)$ [ref] .

Theory of inverse beta decay for reactor antineutrinos · Heavy baryon chiral perturbation theory · 0.99

Compares with it 3 papers

That estimate is essentially the same as the error found for the universal radiative corrections to neutron decay and superallowed beta decays [ref] .

Nucleon Axial Radius and Muonic Hydrogen - A New Analysis and Review · Radiative corrections · 0.95
While reducing the existing theory uncertainty in Ref. [ref] by a half, the new result also showed a significant shift in the central value.

Radiative corrections to semileptonic beta decays: Progress and challenges · $_γW^V$: DR analysis · 0.88
An updated analysis [ref] of the latter agrees with the sense of the shift but finds a result intermediate to that of Refs. [ref] .

Neutron Stars with Baryon Number Violation, Probing Dark Sectors · Constraints from empirical studies of neutron $β$ decay within the SM · 0.93

Cites it as background 6 papers

Various approaches to computing $_γW^V A$ range from earlier works by Marciano and Sirlin [ref] to more recent dispersive analyses by Seng et al [ref] .

Lattice QCD Calculation of Electroweak Box Contributions to Superallowed Nuclear and Neutron Beta Decays · Introduction · 0.98
Despite a long history in their evaluation [ref] , it has proven challenging to quantify and ideally remove the remaining model dependence in these corrections, and substantial effort has been invested in recent years to address this issue using dispersion relations, lattice QCD, effective field theory (EFT), and ab-initio nuclear-structure methods [ref] .

Pion $\beta$ decay and $\tau\to\pi\pi\nu_\tau$ beyond leading logarithms · Introduction · 0.97
The various radiative corrections (including $Δ_RC^(0^+ →0^+)$) are discussed in detail in Refs. [ref] .

Probing Novel Scalar and Tensor Interactions from (Ultra)Cold Neutrons to the LHC · 0→0 transitions and scalar interactions · 0.92

Discussion

Disagree with the review, or know something it missed? Leave a comment, highlight any passage above to comment on it, or challenge this review formally.

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