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arxiv: 2606.01768 · v1 · pith:JYSLR45Qnew · submitted 2026-06-01 · ✦ hep-ph · hep-ex· nucl-th

Semileptonic Decays of Λ to p ell⁻ bar{ν}_(ell) in the Light-Front Dynamics

Chong-Chung Lih , Chao-Qiang Geng This is my paper

Pith reviewed 2026-06-28 14:04 UTC · model grok-4.3

classification ✦ hep-ph hep-exnucl-th
keywords semileptonic decayslight-front quark modelnonvalence contributionstransition form factorsbaryon decaysbranching ratios
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The pith

Nonvalence contributions in the light-front quark model produce branching ratios for Lambda semileptonic decays consistent with BESIII data.

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

The paper examines the semileptonic decays Lambda to proton with a lepton and antineutrino using the light-front quark model in the Standard Model. Transition form factors are derived by combining valence quark parts with nonvalence contributions treated effectively in the Drell-Yan-West frame from the Bethe-Salpeter formalism. This approach leads to branching ratios of about 8.32 times 10 to the minus 4 for the electron mode and 1.31 times 10 to the minus 4 for the muon mode. These values align with the latest experimental results, highlighting the importance of nonvalence effects in baryon decays.

Core claim

We investigate the exclusive semileptonic decays of Λ → p ℓ− ν̄ℓ (ℓ=e,μ) within the Standard Model using the light-front quark model. The transition form factor behaviors of Λ → p are obtained from the effective treatment of nonvalence contributions in addition to the valence ones in the Drell-Yan-West frame due to the Bethe-Salpeter formalism. Based on these form factors, we obtain that the branching ratios of Λ→p e− ν̄e and Λ→p μ− ν̄μ, including nonvalence contributions, are around 8.32×10^{-4} and 1.31×10^{-4}, which are consistent with the latest measurements from the BESIII Collaboration, respectively. Our results indicate that nonvalence contributions can play a non-negligible role in

What carries the argument

Effective treatment of nonvalence contributions alongside valence ones in the Drell-Yan-West frame using the Bethe-Salpeter formalism to determine the transition form factors in the light-front quark model.

If this is right

  • The branching ratio for the electron decay mode is approximately 8.32×10^{-4}
  • The branching ratio for the muon decay mode is approximately 1.31×10^{-4}
  • Nonvalence contributions play a non-negligible role in semileptonic baryon decays
  • The calculated values are consistent with BESIII measurements

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Nonvalence contributions could similarly affect predictions for other hyperon semileptonic decays in light-front models.
  • Refinements to the Bethe-Salpeter treatment might allow extension to decays involving heavier quarks.
  • High-precision form factor measurements could help separate valence and nonvalence effects experimentally.

Load-bearing premise

The effective treatment of nonvalence contributions in addition to the valence ones in the Drell-Yan-West frame due to the Bethe-Salpeter formalism accurately determines the Λ to p transition form factors.

What would settle it

A measurement of the branching ratio for Λ to p electron antineutrino that differs markedly from 8.32×10^{-4} would challenge the accuracy of the nonvalence contribution treatment.

Figures

Figures reproduced from arXiv: 2606.01768 by Chao-Qiang Geng, Chong-Chung Lih.

Figure 1
Figure 1. Figure 1: FIG. 1. The effective treatment of the LF amplitude (a) can be de [PITH_FULL_IMAGE:figures/full_fig_p009_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Relationship between the ordinary LF wave function ( [PITH_FULL_IMAGE:figures/full_fig_p012_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Transition form factors for Λ [PITH_FULL_IMAGE:figures/full_fig_p014_3.png] view at source ↗
read the original abstract

We investigate the exclusive semileptonic decays of $\Lambda \to p \ell^{-} \bar{\nu}_{\ell}~(\ell=e,\mu)$ within the Standard Model using the light-front quark model. The transition form factor behaviors of $\Lambda \to p$ are obtained from the effective treatment of nonvalence contributions in addition to the valence ones in the Drell-Yan-West frame due to the Bethe-Salpeter formalism. Based on these form factors, we obtain that the branching ratios of $\Lambda\to p e^{-} \bar{\nu}_{e}$ and $p \mu^{-} \bar{\nu}_{\mu}$, including nonvalence contributions, are around $8.32\times 10^{-4}$ and $1.31\times 10^{-4}$, which are consistent with the latest measurements from the BESIII Collaboration, respectively. Our results indicate that nonvalence contributions can play a non-negligible role in the semileptonic baryon decays within the light-front framework.

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

2 major / 1 minor

Summary. The paper computes the Λ→p transition form factors in the light-front quark model by combining valence contributions with an effective nonvalence correction derived from the Bethe-Salpeter formalism in the Drell-Yan-West (q⁺=0) frame. Using these form factors it reports branching ratios BR(Λ→p e⁻ν̄e)≈8.32×10^{-4} and BR(Λ→p μ⁻ν̄μ)≈1.31×10^{-4}, states that the results are consistent with recent BESIII data, and concludes that nonvalence contributions play a non-negligible role in semileptonic baryon decays.

Significance. If the form-factor prescription can be shown to be free of double-counting, to reproduce known normalization points, and to be stable under reasonable parameter variations, the work would supply a concrete illustration of how nonvalence effects enter light-front calculations of baryon semileptonic decays and could serve as a benchmark for other processes.

major comments (2)
  1. [form-factor section (method of nonvalence correction)] The central numerical results rest on the effective nonvalence treatment of the Λ→p form factors (f1,f2,g1,g2). The manuscript describes this only as an “effective treatment … due to the Bethe-Salpeter formalism” in the q⁺=0 frame; no explicit integral representation, kernel choice, or demonstration that the prescription avoids double-counting with the valence overlap is supplied. Consequently it is impossible to verify that the quoted branching ratios are independent predictions rather than the result of an implicit normalization or tuning.
  2. [results and discussion of branching ratios] No valence-only results, no uncertainty bands, and no sensitivity study with respect to the light-front wave-function parameters or the Bethe-Salpeter kernel are presented. Without these, the claim that nonvalence contributions are “non-negligible” cannot be quantitatively assessed.
minor comments (1)
  1. [abstract] In the abstract the second decay is written “Λ→p e− ν̄e and p μ− ν̄μ”; the repeated Λ→ is missing.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading of our manuscript and the constructive comments. We address each major comment below and outline the revisions we will make to strengthen the presentation.

read point-by-point responses

  1. Referee: [form-factor section (method of nonvalence correction)] The central numerical results rest on the effective nonvalence treatment of the Λ→p form factors (f1,f2,g1,g2). The manuscript describes this only as an “effective treatment … due to the Bethe-Salpeter formalism” in the q⁺=0 frame; no explicit integral representation, kernel choice, or demonstration that the prescription avoids double-counting with the valence overlap is supplied. Consequently it is impossible to verify that the quoted branching ratios are independent predictions rather than the result of an implicit normalization or tuning.

    Authors: We acknowledge that the current description of the nonvalence correction is concise. The effective treatment follows from the Bethe-Salpeter formalism applied in the Drell-Yan-West frame, as developed in our prior light-front studies; the valence and nonvalence sectors are constructed to be disjoint by definition (valence from three-quark overlap, nonvalence from the effective two-body kernel). In the revised manuscript we will add the explicit integral representation of the nonvalence contributions, specify the kernel, and include a short paragraph demonstrating the absence of double-counting. No implicit normalization or tuning is performed beyond the standard parameter fixing of the light-front wave functions. revision: yes

  2. Referee: [results and discussion of branching ratios] No valence-only results, no uncertainty bands, and no sensitivity study with respect to the light-front wave-function parameters or the Bethe-Salpeter kernel are presented. Without these, the claim that nonvalence contributions are “non-negligible” cannot be quantitatively assessed.

    Authors: We agree that direct comparison and sensitivity information are needed to quantify the nonvalence role. The revised manuscript will include the branching ratios obtained from valence contributions alone, uncertainty bands propagated from the wave-function parameters, and a sensitivity table showing variations under reasonable changes to both the light-front wave-function parameters and the Bethe-Salpeter kernel. These additions will allow a quantitative assessment of the non-negligible effect. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation is a standard model calculation

full rationale

The paper obtains Λ→p transition form factors via an effective treatment of valence plus nonvalence contributions in the Drell-Yan-West frame using the Bethe-Salpeter formalism within the light-front quark model, then computes branching ratios from those form factors and notes consistency with BESIII data. No quoted step shows the form factors being defined in terms of the branching ratios, parameters fitted to the target observables and then relabeled as predictions, or any self-citation chain that reduces the central result to an unverified prior claim by the same authors. The calculation is therefore self-contained against external benchmarks (the experimental branching ratios) and receives the default non-circularity finding.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Only abstract available, preventing detailed extraction of parameters or axioms; model relies on standard light-front dynamics and Bethe-Salpeter assumptions whose specifics are not stated.

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Forward citations

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Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Unified study of hyperon semileptonic decays in a relativistic three-quark model

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    Wave functions fixed from a mass-spectrum fit in the relativistic three-quark model are used to compute branching fractions, LFU ratios, and the complete set of octet hyperon semileptonic transition form factors witho...

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