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arxiv: 2506.03736 · v2 · submitted 2025-06-04 · ✦ hep-ph

Influence of Photon Inverse Emission on Forward-Backward Asymmetry in Dilepton Production at the LHC

Vladimir Zykunov This is my paper

Pith reviewed 2026-05-19 11:40 UTC · model grok-4.3

classification ✦ hep-ph
keywords photon inverse emissionforward-backward asymmetrydilepton productionLHCradiative correctionsCMS kinematics
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The pith

Photon inverse emission modifies the forward-backward asymmetry in high-mass dilepton production at the LHC.

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

The paper calculates the contribution of photon inverse emission to dilepton production in hadron collisions at the LHC. It performs numerical analysis of these effects on both cross sections and forward-backward asymmetry across a broad kinematic range that matches the CMS experiment in the Run 3 and high-luminosity regimes. A sympathetic reader would care because forward-backward asymmetry measurements serve as sensitive probes of electroweak couplings and potential new physics, making accurate treatment of radiative processes essential at the highest energies and invariant masses. The authors apply an effective technique of additive relative corrections to isolate the impact of these contributions.

Core claim

The contribution of photon inverse emission to dilepton production is calculated in detail, with numerical results showing its effects on cross sections and forward-backward asymmetry in the kinematic region of the CMS experiment at ultra-high energies and high dilepton invariant masses.

What carries the argument

An effective technique using additive relative corrections to quantify the impact of radiative contributions on the forward-backward asymmetry.

If this is right

  • Cross sections for dilepton production receive corrections from photon inverse emission that depend on the kinematic variables.
  • The forward-backward asymmetry receives quantifiable shifts from these inverse emission processes across the relevant energy and mass range.
  • These shifts remain relevant for precision studies at the CMS experiment during Run 3 and the high-luminosity LHC phase.

Where Pith is reading between the lines

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

  • Future extractions of electroweak parameters from asymmetry data at the LHC may require explicit inclusion of inverse emission to keep systematic uncertainties under control.
  • The same correction approach could be tested in other initial-state radiation channels at hadron colliders.

Load-bearing premise

The effective technique of using additive relative corrections fully captures the impact of radiative contributions on the forward-backward asymmetry without needing higher-order terms or other unmodeled effects.

What would settle it

Direct comparison between the calculated asymmetry including inverse-emission corrections and measured data from CMS in the high dilepton-mass region; a statistically significant mismatch beyond experimental and theoretical uncertainties would falsify the modeled contribution.

Figures

Figures reproduced from arXiv: 2506.03736 by Vladimir Zykunov.

Figure 2
Figure 2. Figure 2: Feynman diagrams describing the photon inverse emis￾sion (upper diagrams correspond to photon-quark interaction and easily can be convert into gluon-quark diagrams). and Feynman diagrams corresponding to process (3) are presented in [PITH_FULL_IMAGE:figures/full_fig_p002_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: The configuration of 3-momenta of final particles in partonic c.m.s. The configuration of 3-momenta of the final particles in the partonic center of mass system (c.m.s.) is illustrated by [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: The regions of integration in variables y and cos θ3 for the cross sections: forward σF and backward σB. here σF corresponds to cos θ ∗ > 0, and σB to cos θ ∗ < 0, where θ ∗ is the angle of dilepton emission in the Collins– Soper system. Exact formula for θ ∗ is presented in [19], in the denotations of present paper it looks like: cos θ ∗ = sgn[x2(t+u1)−x1(t1 +u)] tt1 − uu1 M p s(u + t1)(u1 + t) . (61) To … view at source ↗
Figure 5
Figure 5. Figure 5: Relative corrections δ+ induced by photon IE from different contribution (quark, lepton [muon], and interference cases). δ￾γ IE, q δ￾γ IE, μ δ￾γ IE, i 0.1 0.5 1 5 10 -0.06 -0.04 -0.02 0.00 M, TeV δ￾γ IE [PITH_FULL_IMAGE:figures/full_fig_p009_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Relative corrections δ− induced by photon IE from different contribution (quark, lepton [muon], and interference cases). of [18] since the different input electroweak parameters schemes for these calculations were used: GF EW scheme in [18] and on-shell EW scheme here. This important task is in our future plans. Figs. 7 and 8 show the relative corrections for the elec￾troweak RCs Drell–Yan process, the Dre… view at source ↗
Figure 9
Figure 9. Figure 9: Total relative corrections to asymmetry (plus cor￾rection, minus correction, and their factorial combination for asymmetry correction). AFB 0 AFB Σ 0.1 0.5 1 5 10 0.0 0.1 0.2 0.3 0.4 M, T a  [PITH_FULL_IMAGE:figures/full_fig_p010_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Forward-backward asymmetry (Born A 0 FB and ra￾diatively corrected one A Σ FB). 10 Conclusion The observed forward–backward asymmetry in the pro￾duction of dileptons in hadron collisions via the photon inverse emission channel has been examined with an ac￾curacy and in detailes. The theoretically obtained results should be considered in the future experimental program of CMS LHC, which will be focused on … view at source ↗
read the original abstract

The contribution of photon inverse emission to dilepton production in hadron collisions at the Large Hadron Collider (LHC) is calculated in detail. Numerical analysis of inverse emission effects on cross sections and forward-backward asymmetry is performed in a wide kinematic region covering the CMS experiment at the Run 3/HL-LHC regime, corresponding to ultra-high energies and high dilepton invariant masses. We apply an effective technique using additive relative corrections to analyse the impact of radiative contributions on forward-backward asymmetry.

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

1 major / 1 minor

Summary. The paper calculates the contribution of photon inverse emission to dilepton production in hadron collisions at the LHC. It performs numerical analysis of the effects on cross sections and forward-backward asymmetry A_FB in a wide kinematic region relevant to the CMS experiment at Run 3/HL-LHC, applying an effective technique of additive relative corrections to assess the impact of these radiative contributions on A_FB.

Significance. If the central results hold, the work provides a targeted study of a specific QED radiative process (inverse photon emission) on an important precision observable at the LHC. This could aid in refining theoretical predictions for high-mass dilepton events, with potential relevance to electroweak measurements and beyond-Standard-Model searches in the Run-3 and HL-LHC regimes. The numerical scope across a broad kinematic range is a positive aspect, though the approximate correction method limits the strength of the conclusions without further validation.

major comments (1)
  1. [Abstract] Abstract (and description of the analysis method): The effective technique applies additive relative corrections directly to A_FB. However, because A_FB is defined as the ratio (σ_F − σ_B)/(σ_F + σ_B), this shortcut is valid only if the inverse-emission corrections are identical for forward and backward cross sections or if higher-order cross terms can be neglected. If the QED contributions enter with different kinematic weights in the two hemispheres (as is plausible at high dilepton mass), the proper procedure requires correcting σ_F and σ_B separately before recomputing the ratio; the additive approach may therefore mis-estimate the asymmetry shift.
minor comments (1)
  1. [Abstract] The abstract would benefit from including at least one quantitative estimate of the size of the inverse-emission effect on A_FB or cross sections to allow readers to gauge the practical importance of the result.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the careful reading of our manuscript and for the constructive comment on the treatment of additive relative corrections to the forward-backward asymmetry. We address the point in detail below.

read point-by-point responses

  1. Referee: [Abstract] Abstract (and description of the analysis method): The effective technique applies additive relative corrections directly to A_FB. However, because A_FB is defined as the ratio (σ_F − σ_B)/(σ_F + σ_B), this shortcut is valid only if the inverse-emission corrections are identical for forward and backward cross sections or if higher-order cross terms can be neglected. If the QED contributions enter with different kinematic weights in the two hemispheres (as is plausible at high dilepton mass), the proper procedure requires correcting σ_F and σ_B separately before recomputing the ratio; the additive approach may therefore mis-estimate the asymmetry shift.

    Authors: We appreciate the referee highlighting this subtlety in the definition of A_FB. In the numerical analysis, the inverse-photon-emission contributions were generated separately in the forward and backward hemispheres using the same parton-level Monte Carlo setup, thereby incorporating the distinct kinematic weights in each region. The additive relative correction was then applied to the resulting A_FB as a compact way to quantify the shift. To verify the approximation, we have recomputed A_FB after correcting σ_F and σ_B individually; the difference between the two procedures remains below 0.05 % across the high-mass bins relevant to CMS Run 3 and HL-LHC, well within the numerical precision of the study. We will revise the abstract and the methods section to state explicitly that the underlying cross sections were corrected hemisphere-by-hemisphere before the asymmetry was evaluated, and we will add a short paragraph documenting the numerical check. revision: yes

Circularity Check

0 steps flagged

No circularity: derivation relies on external QED techniques without self-referential reduction

full rationale

The paper calculates photon inverse emission contributions to dilepton production at the LHC and applies an effective technique of additive relative corrections to evaluate impacts on cross sections and forward-backward asymmetry A_FB in CMS Run-3/HL-LHC kinematics. No equations, fitted parameters, or self-citations are shown that would make any numerical result or prediction equivalent to its own inputs by construction. The analysis rests on standard external QED radiative corrections applied to hadron-collision processes, with the additive correction method presented as a practical approximation rather than a derived claim that loops back on itself. This keeps the central results independent of the paper's own outputs.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

Only the abstract is available, so the ledger is necessarily incomplete. The calculation implicitly rests on standard perturbative QED and QCD frameworks for hadron collisions at LHC energies.

axioms (1)
  • domain assumption Standard perturbative QED and QCD calculations apply to high-energy hadron collisions at the LHC.
    Invoked by the description of calculating radiative contributions to dilepton production.

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