Pith. Sign in

REVIEW

Update on transverse-spin azimuthal asymmetries in single-hadron SIDIS on transversely polarised deuterons at COMPASS

PaperPDF from arXiv

data files

ReviewThe objections and verdict, as JSON Paper breakdownThe authors' claims, conditions and measurements, as JSON Signed receiptProof this review has not been altered
X Bluesky LinkedIn Reddit Hacker News
Artur Hoghmrtsyan (on behalf of the COMPASS Collaboration)

High Energy Physics - Experiment · Submitted 26 Oct 2026 · 16 references

Pith's verdict: Incremental deuteron SIDIS data from COMPASS, useful for TMD fits, but the extension to eight modulations lacks fit validation — acceptable for a proceedings, needed for a journal paper.

T0 · AI review

How this review was made: An AI referee (deepseek/deepseek-v4-flash) read the paper on October 28, 2026 and answered a fixed list of questions about it. T0 is the starting level every paper gets. The levels describe how deeply Pith has checked the paper, never the authors.

  1. T0 AI review An AI read the paper and answered a fixed list of questions.
  2. T1 Audit Automatic checks that the references and files the paper relies on exist and match.
  3. T2 Compute The paper's code or calculations re-run with the same results.
  4. T3 Formal statement The claims written out in a formal math language a computer can read.
  5. T4 Proof Those claims proved, and the proof checked by computer.

How Pith checks papers →

· 3 major objections · 4 minor · Ask about this paper · The compiled record · Read the full review →
Challenge this review Comment (0) Read on arXiv ↗
Cite ▾
arXiv ID2610.36224 (version 1)
Pith IDX25G657V, Pith's permanent record of this paper and its review
CitationArtur Hoghmrtsyan (on behalf of the COMPASS Collaboration). "Update on transverse-spin azimuthal asymmetries in single-hadron SIDIS on transversely polarised deuterons at COMPASS." arXiv:2610.36224 (2026). https://pith.science/paper/X25G657V
Cite this reviewBibTeX for Pith's review of this paper
Claim paper

Why Pith says this

Highlight any text to comment on it.

Referee report

How Pith checks papers → · Full audit of this paper →

The paper

The paper claims

The COMPASS collaboration reports the simultaneous extraction of all eight transverse-spin azimuthal asymmetries from the complete 2022 deuteron sample, confirming earlier partial-statistics Collins and Sivers results and providing first…

The reading

This paper presents the final full-statistics measurement of all eight transverse-spin azimuthal asymmetries in single-hadron semi-inclusive deep-inelastic scattering (SIDIS) on a transversely polarised deuteron target, using the complete 2022 COMPASS dataset of about 114 million charged hadrons. The Collins and Sivers asymmetries, previously reported with roughly 70% of the data, are confirmed with the full sample and found consistent. The six remaining asymmetries—the pretzelosity, Kotzinian–Mulders, and four subleading-twist modulations—are shown for the first time with full statistics. All measured amplitudes are small and generally compatible with zero, except for a tendency toward opposite signs for positive and negative hadrons at large x in the Collins channel. Combined with existing proton measurements, these results complete a comprehensive COMPASS programme on transverse-spin effects and provide essential input for flavour-separated global analyses of transverse-momentum-dependent parton distributions.

What carries the argument

The central object is the set of eight transverse-spin-dependent azimuthal asymmetries defined in the SIDIS cross-section formula for a transversely polarised target, each corresponding to a distinct modulation in φ_h and φ_S. The amplitudes are extracted simultaneously via a two-dimensional (φ_h, φ_S) extended unbinned maximum-likelihood fit, corrected for target polarisation, dilution factor, and depolarisation factors. The analysis uses the same selection and procedure as the earlier partial-statistics publication, leveraging the full 2022 dataset with approximately 114 million selected charged hadrons.

Extended reading notes

Core claim

Using the complete 2022 transversely polarised deuteron dataset, the COMPASS collaboration has simultaneously extracted all eight azimuthal asymmetries that appear in single-hadron SIDIS when the target is transversely polarised. The Collins and Sivers results from the full sample are consistent with the previously published analysis based on about 70% of the statistics, and the other six asymmetries are now reported with the same high-statistics sample for the first time. The Collins amplitudes remain small, with an opposite-sign tendency for positive and negative hadrons in the largest-x bin; the Sivers asymmetry is small and compatible with zero across all kinematic bins. The pretzelosity asymmetry is compatible with zero, and the Kotzinian–Mulders asymmetry shows no significant signal beyond a possible positive tendency at large x. The four subleading-twist asymmetries ($A^{{sin φ_S}}$_{UT}, $A^{{sin(2φ_h-φ_S)}}$_{UT}, $A^{{cos φ_S}}$_{LT}, $A^{{cos(2φ_h-φ_S)}}$_{LT}) are all generally small and zero-compatible within uncertainties.

Load-bearing premise

The analysis procedure is assumed identical to that used for the earlier partial-statistics analysis without revalidation for the full sample; any systematic effect that varies over the final 30% of data or new time-dependent detector effects could affect the results.

Editorial extensions

If this is right

  • The full-statistics deuteron asymmetries, combined with existing proton data, allow a refined flavour separation of the transversity and Sivers distributions, particularly constraining the down-quark contributions.
  • The new pretzelosity and Kotzinian–Mulders measurements provide complementary input for global extractions of the TMD PDFs h^{⊥}_{1T} and g_{1T}.
  • The subleading-twist asymmetries, though small, can serve as constraints for higher-twist correlation functions and tests of Wandzura–Wilczek-type approximations in SIDIS.
  • The consistency check between the partial and full statistics validates the stability of the COMPASS analysis procedure and strengthens confidence in the previously published Collins and Sivers results.

Reading between the lines

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

  • If the deuteron Collins asymmetry's opposite-sign tendency at large x holds with future higher-statistics data, it would reinforce a similar pattern seen in proton data, supporting the sign-flip prediction for the transversity distribution between up and down quarks.
  • The persistent smallness of the Sivers asymmetry on deuterons compared to protons may sharpen the evidence for a flavour-dependent Sivers function, with implications for the orbital angular momentum interpretation.
  • The compatibility with zero of the four subleading-twist asymmetries across essentially all kinematic bins suggests that genuine twist-3 contributions to these modulations are not required at the current precision, which could simplify global TMD analyses.
  • The paper's reported results are still preliminary; if the final systematic uncertainties include additional corrections (e.g., acceptance effects from the full dataset), small shifts in the non-zero Collins bins cannot be ruled out.
Original abstract

Over the years, the COMPASS experiment at CERN has pursued an extensive SIDIS programme aimed at a comprehensive understanding of the structure of the nucleon, using a high-energy muon beam and polarised targets. Within this programme, measurements with a transversely polarised deuteron target were performed in 2022 using the 160 GeV/c muon beam. In single-hadron SIDIS on such a target, eight transverse-spin-dependent azimuthal asymmetries arise, providing sensitivity to several transverse-momentum-dependent parton distribution functions and to subleading-twist partonic correlations. We report the simultaneous extraction of all eight asymmetries from the complete 2022 deuteron sample. The Collins and Sivers asymmetries, previously presented using about 70% of the 2022 statistics, are updated with the full sample and found consistent with the earlier result, while the six remaining asymmetries are presented for the first time with the full 2022 statistics. Combined with the existing proton results, these measurements complete a comprehensive COMPASS programme on transverse-spin effects in SIDIS, providing essential input for global analyses.

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-1.13.0 via TypeSafe API, question bank abstract-p1-20260923, 2026-10-28: 1 request, 5,163 input tokens.

What the abstract itself states, as probabilities: claims first 0.33 · states limitation 0.11 · human participants 0.02 · controlled comparison 0.09 · randomized assignment 0.01 · states quantitative result 0.51 · compares with prior results 0.94 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; .

Over the years, the COMPASS experiment at CERN has pursued an extensive SIDIS programme aimed at a comprehensive understanding of the structure of the nucleon, using a high-energy muon beam and polarised targets. Within this programme, measurements with a transversely polarised deuteron target were performed in 2022 using the 160 GeV/c muon beam. In single-hadron SIDIS on such a target, eight transverse-spin-dependent azimuthal asymmetries arise, providing sensitivity to several transverse-momentum-dependent parton distribution functions and to subleading-twist partonic correlations. We report the simultaneous extraction of all eight asymmetries from the complete 2022 deuteron sample. The Collins and Sivers asymmetries, previously presented using about 70% of the 2022 statistics, are updated with the full sample and found consistent with the earlier result, while the six remaining asymmetries are presented for the first time with the full 2022 statistics. Combined with the existing proton results, these measurements complete a comprehensive COMPASS programme on transverse-spin effects in SIDIS, providing essential input for global analyses.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 Over the years, the COMPASS experiment at CERN has pursued an extensive SIDIS programme aimed at a comprehensive understanding of the structure of the nucleon, using a high-energy muon beam and polarised targets. background 1.00 0.44 0.02 asserted 1.00
s1 Within this programme, measurements with a transversely polarised deuteron target were performed in 2022 using the 160 GeV/c muon beam. method 0.81 0.84 0.03 asserted 1.00
s2 In single-hadron SIDIS on such a target, eight transverse-spin-dependent azimuthal asymmetries arise, providing sensitivity to several transverse-momentum-dependent parton distribution functions and to subleading-twist partonic correlations. background 0.95 0.09 0.06 asserted 1.00
s3 We report the simultaneous extraction of all eight asymmetries from the complete 2022 deuteron sample. contribution 0.90 0.97 0.50 asserted 1.00
s4 The Collins and Sivers asymmetries, previously presented using about 70% of the 2022 statistics, are updated with the full sample and found consistent with the earlier result, while the six remaining asymmetries are presented for the first time with the full 2022 statistics. result 0.81 0.95 0.36 asserted 0.98
s5 Combined with the existing proton results, these measurements complete a comprehensive COMPASS programme on transverse-spin effects in SIDIS, providing essential input for global analyses. interpretation 0.98 0.66 0.57 asserted 1.00

What kind of paper the classifier reports this is: empirical study 1.00 · evidence from observation or experiment 0.66.

What was examined, and what was not

sources read
  • arXiv listing abstract v1
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • 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

Figures
Figure 2. −0.05 0 0.05 h Coll A LiD 2022: preliminary 6 2010: PLB 717(2012)376 NH3 0.2 0.4 0.6 0.8 0.05 0 0.05 COMPASS data ' h X + ) → µ ↑ (p ↑ d + µ 0.5 1 1.5 0.05 0 0.05 + h −2 10 −1 10 x −0.05 0 0.05 h Coll A LiD 2022: preliminary 6 2010: PLB 717(2012)376 NH3 0.2 0.4 0.6 0.8 z 0.05 0 0.05 0.5 1 1.5 (GeV/c) T p 0.05 0 0.05 − h −0.05 0 0.05 h Siv A LiD 2022: preliminary 6 2010: PLB 717(2012)376 NH3 0.2 0.4 0.6 0.8 0.05 0 0.05 COMPASS data ' h X + ) → µ ↑ (p ↑ d + µ 0.5 1 1.5 0.05 0 0.05 + h −2 10 −1 10 x −0.05 0 0.05 h Siv A LiD 2022: preliminary 6 2010: PLB 717(2012)376 NH3 0.2 0.4 0.6 0.8…
Figure 3. Full-statistics 2022 deuteron results for the sin(3𝜙h − 𝜙S) pretzelosity (left) and cos(𝜙h − 𝜙S) Kotzinian–Mulders (right) asymmetries as functions of 𝑥, 𝑧, and 𝑝T for positive (red circles) and negative (black triangles) hadrons. The error bars represent the statistical uncertainties; the red and grey bands mark the systematic uncertainties for positive and negative hadrons, respectively. The results are COMPASS preliminary. Across the 𝑥, 𝑧, and 𝑝T projections, the pretzelosity amplitudes fluctuate around zero without a coherent kinematic dependence, whereas the Kotzinian–Mulders…
Figure 4. Full-statistics 2022 deuteron results for 𝐴 sin 𝜙S UT (top left), 𝐴 sin(2𝜙h−𝜙S ) UT (top right), 𝐴 cos 𝜙S LT (bottom left), and 𝐴 cos(2𝜙h−𝜙S ) LT (bottom right), as functions of 𝑥, 𝑧, and 𝑝T for positive (red circles) and negative (black triangles) hadrons. The error bars represent the statistical uncertainties; the red and grey bands mark the systematic uncertainties for positive and negative hadrons, respectively. The results are COMPASS preliminary. 5

Showing 3 of the paper's 4 figures. See all figures in the PDF ↗ Figures reproduced from arXiv:2610.36224 by the authors.

References

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.