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arxiv: 2512.23727 · v2 · pith:BEI2XHUBnew · submitted 2025-12-19 · ✦ hep-ex

Addendum to multiplicities of charged pions, kaons and unidentified charged hadrons on an isoscalar target measured by COMPASS Collaboration

The COMPASS Collaboration This is my paper

Pith reviewed 2026-05-16 21:06 UTC · model grok-4.3

classification ✦ hep-ex
keywords COMPASShadron multiplicitiesisoscalar targetradiative correctionspionskaonsdeep inelastic scatteringDJANGOH
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The pith

COMPASS updates isoscalar hadron multiplicities using DJANGOH radiative corrections

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

This addendum reprocesses COMPASS data on charged pion, kaon, and unidentified hadron multiplicities from an isoscalar target. It replaces the earlier radiative corrections with values obtained from the DJANGOH Monte Carlo generator. The new corrections are larger by up to 12 percent in the low-x high-z region. This step creates methodological consistency with the proton target multiplicities published using the same generator. The resulting tables supersede the 2017 publications.

Core claim

The paper establishes an updated set of multiplicities for positive and negative pions, kaons, and unidentified charged hadrons measured in deep-inelastic muon scattering off an isoscalar target, obtained by re-evaluating QED radiative corrections with the DJANGOH Monte Carlo generator to match the treatment applied to recent proton target data.

What carries the argument

The DJANGOH Monte Carlo generator used to compute QED radiative corrections for the multiplicity extraction

If this is right

  • The new multiplicity tables must replace the 2017 values in any combined COMPASS analyses of isoscalar and proton data.
  • Differences of up to 12 percent appear in the low-x high-z kinematic region and propagate into extracted fragmentation functions.
  • All future COMPASS multiplicity publications will adopt the DJANGOH correction procedure for consistency.
  • The updated results allow direct comparison with proton target measurements without correction-related offsets.

Where Pith is reading between the lines

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

  • The change may shift extracted quark fragmentation functions when the updated isoscalar data are combined with other experiments.
  • Other deep-inelastic scattering experiments using older radiative correction methods may need similar re-evaluations to maintain precision.
  • The size of the correction difference underscores the sensitivity of multiplicity measurements to the treatment of QED radiation at low x and high z.

Load-bearing premise

That the DJANGOH Monte Carlo generator supplies more accurate QED radiative corrections than the method used in the 2017 publications.

What would settle it

A direct comparison showing that the original 2017 radiative corrections reproduce independent data better than the DJANGOH-based corrections in the low-x high-z bins would falsify the need for the update.

Figures

Figures reproduced from arXiv: 2512.23727 by The COMPASS Collaboration.

Figure 1
Figure 1. Figure 1: Left panel: comparison of RC factors for positive pions in a selected (x,y) bin as a function of z using DJANGOH-MC (red circles) and TERAD from Ref. [1] (black circles), right panel: comparison of RC factors for positive kaons in a selected (x, y) bin as a function of z using DJANGOH-MC (red squares) and based on TERAD from Ref. [2] (black squares). In the left panel of [PITH_FULL_IMAGE:figures/full_fig_… view at source ↗
Figure 2
Figure 2. Figure 2: Left panel: the values of RCDJANGOH for π ± and K± in a selected (x,y) bin as a function of z (for clarity staggered horizontally), right panel: the values of RCDJANGOH obtained for proton and isoscalar targets in a selected (x,y) bin as a function of z. 3 New multiplicity results To obtain new isoscalar multiplicities, radiative corrections are removed from the previous results [1, 2] and the new RCDJANGO… view at source ↗
Figure 3
Figure 3. Figure 3: Values of dMπ + ratio−1 /dz as a function of z for nine bins of x and five bins of y (for clarity staggered vertically by α). 4 Summary In this Addendum, we present updated multiplicity values for an isoscalar target, published in Phys. Lett. B 764 (2017) 1 and Phys. Lett. B 767 (2017) 133. They are recalculated using radiative corrections obtained with the DJANGOH Monte Carlo generator. These radiative co… view at source ↗
Figure 4
Figure 4. Figure 4: Values of dMK + ratio−1 /dz as a function of z for nine bins of x and five bins of y (for clarity staggered vertically by α). them enables a consistent treatment of COMPASS isoscalar target multiplicity results with the proton multiplicities, recently published in Phys. Rev. D 112 (2025) 012002. Acknowledgements We express our gratitude to H. Spiesberger for his valuable assistance in the use of the DJANGO… view at source ↗
read the original abstract

The COMPASS Collaboration has recently published an article "Multiplicities of positive and negative pions, kaons, and unidentified hadrons from deep-inelastic scattering of muons off a liquid hydrogen target", Phys. Rev. D 112 (2025) 012002. In contrast to earlier COMPASS publications on similar topics, the aforementioned article features an enhanced treatment of QED radiative corrections, employing the DJANGOH Monte Carlo generator. This methodological improvement led to corrections that are up to 12% larger in the low-x, high-z region compared to the previously applied ones. To ensure consistent treatment of COMPASS data sets obtained using both isoscalar and proton targets, this paper presents an updated set of isoscalar multiplicities based on DJANGOH-derived radiative corrections. The present results supersede those published in Phys. Lett. B 764 (2017) 1 and Phys. Lett. B 767 (2017) 133.

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 / 1 minor

Summary. The manuscript is an addendum that recomputes the multiplicities of charged pions, kaons, and unidentified hadrons from muon deep-inelastic scattering on an isoscalar target using the DJANGOH Monte Carlo generator for QED radiative corrections. This update ensures methodological consistency with the recent proton-target publication (Phys. Rev. D 112 (2025) 012002) and supersedes the results published in Phys. Lett. B 764 (2017) 1 and Phys. Lett. B 767 (2017) 133, with the corrections being up to 12% larger in the low-x, high-z region.

Significance. If the updated multiplicities are adopted, they enable uniform treatment of COMPASS isoscalar and proton-target datasets, which is valuable for global analyses of fragmentation functions and parton distributions. The paper provides explicit quantification of the correction differences without introducing new data, binning changes, or fitted parameters, supporting transparency in the re-processing.

minor comments (1)
  1. [Abstract] The abstract and introduction could briefly state that the kinematic binning and data selection remain identical to the 2017 publications, to make the scope of the update immediately clear to readers.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive assessment of the addendum and the recommendation to accept the manuscript. The update ensures consistency with the recent proton-target results using DJANGOH radiative corrections, and we appreciate the recognition of its value for global analyses of fragmentation functions.

Circularity Check

0 steps flagged

No significant circularity

full rationale

The paper is a concise addendum whose sole purpose is to recompute existing isoscalar multiplicity tables by applying the identical DJANGOH Monte Carlo radiative-correction procedure already used in the 2025 proton-target publication. Multiplicities are extracted directly from experimental data; the only change is substitution of an external, independently developed generator for the prior correction method. No parameters are fitted to the target result, no self-definitional equations appear, and the reported numerical shifts are the direct numerical consequence of the re-processing rather than a derived prediction. The derivation chain therefore remains self-contained against external benchmarks and does not reduce to its own inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is an experimental data-update paper. No new free parameters, axioms, or invented entities are introduced; the work applies an established Monte Carlo generator to reprocess previously collected data.

pith-pipeline@v0.9.0 · 5471 in / 1137 out tokens · 72807 ms · 2026-05-16T21:06:44.430246+00:00 · methodology

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Reference graph

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