Transverse momentum dependent multiplicities of hadrons produced in DIS at COMPASS
Pith reviewed 2026-05-24 20:10 UTC · model grok-4.3
The pith
The paper presents preliminary measurements of transverse momentum dependent multiplicities of charged hadrons produced in deep inelastic scattering off unpolarized protons.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The central claim is that the transverse momentum dependent multiplicities of charged hadrons have been measured in deep inelastic scattering off unpolarized protons and are shown as a function of P_hT² in bins of x, Q² and z, with the presented results being preliminary and based on part of the available data sample.
What carries the argument
The multiplicities of charged hadrons studied as a function of the square of the hadron transverse momentum with respect to the virtual photon direction, examined separately in bins of the Bjorken variable x, the photon virtuality Q² and the energy fraction z carried by the hadron.
If this is right
- The multiplicities are now available for a proton target in addition to prior isoscalar target results.
- The dependence on transverse momentum squared can be inspected independently within each chosen bin of the kinematic variables.
- Refinement of these preliminary values will follow from analysis of the remaining data.
Where Pith is reading between the lines
- The binned multiplicities supply input that can constrain models of transverse momentum distributions inside the proton.
- Comparison of proton-target results with isoscalar ones may highlight differences arising from proton versus neutron contributions.
- Verification against the complete dataset would test whether the current selection introduces any systematic offsets.
Load-bearing premise
The preliminary analysis performed on a fraction of the available data sample is representative of the full data set and free of significant unaccounted selection or detector biases.
What would settle it
Completion of the analysis on the full data sample that yields substantially different multiplicity values or uncovers large unaccounted biases in the current selection or detector response.
read the original abstract
The COMPASS Collaboration measured the transverse momentum dependent multiplicities of charged hadrons produced in Deep Inelastic Scattering (DIS) off unpolarized protons. Complementing previous COMPASS measurements obtained with an isoscalar target, the data have been collected in 2016 and 2017 with 160 GeV/$c$ muon beams and a liquid hydrogen target. The multiplicities are studied as a function of the square of the hadron transverse momentum with respect to the virtual photon direction $P_{hT}^2$ in bins of the Bjorken variable $x$, of the photon virtuality $Q^2$ and of the fraction $z$ of the photon energy carried by the hadron. Preliminary results of this analysis, performed on a fraction of the available data sample, are shown here for the first time.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript reports preliminary measurements by the COMPASS Collaboration of transverse-momentum-dependent multiplicities of charged hadrons produced in deep-inelastic scattering off unpolarized protons. Data were collected in 2016–2017 with a 160 GeV/c muon beam and liquid-hydrogen target; multiplicities are presented versus P_hT² in bins of x, Q² and z, complementing earlier isoscalar-target results. The analysis uses only a fraction of the available sample.
Significance. If the full analysis with documented selection, acceptance corrections and systematic uncertainties were completed and shown to be representative, the results would supply new proton-target input for global TMD fits and tests of factorization in the current-fragmentation region.
major comments (2)
- [Abstract] Abstract: the central observables are extracted from an unspecified fraction of the 2016–2017 data with no quantitative statement of the fraction used, the run-period selection criteria, or any stability/cross-check distributions demonstrating that the analyzed subset is free of unaccounted selection or detector biases. Because the reported P_hT²-dependent multiplicities are the primary result, this omission directly affects the quoted values.
- [Abstract] Abstract: no information is supplied on analysis cuts, background subtraction, acceptance corrections, or systematic uncertainties. These elements are load-bearing for any experimental multiplicity measurement and are required to assess whether the preliminary distributions can be compared with theory or other experiments.
Simulated Author's Rebuttal
We thank the referee for the careful assessment of our preliminary results. The comments correctly identify areas where the abstract could be strengthened to better contextualize the data subset and analysis status. We address each point below and will update the manuscript accordingly.
read point-by-point responses
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Referee: [Abstract] Abstract: the central observables are extracted from an unspecified fraction of the 2016–2017 data with no quantitative statement of the fraction used, the run-period selection criteria, or any stability/cross-check distributions demonstrating that the analyzed subset is free of unaccounted selection or detector biases. Because the reported P_hT²-dependent multiplicities are the primary result, this omission directly affects the quoted values.
Authors: We agree that the abstract would benefit from a quantitative indication of the data fraction. In the revised version we will state the approximate fraction of the 2016–2017 sample that was analyzed and note the run-period selection criteria applied. Detailed stability and cross-check distributions are internal to the ongoing analysis and are not customarily shown in preliminary reports; we will nevertheless add a sentence confirming that the selected subset passed standard data-quality and stability checks. revision: yes
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Referee: [Abstract] Abstract: no information is supplied on analysis cuts, background subtraction, acceptance corrections, or systematic uncertainties. These elements are load-bearing for any experimental multiplicity measurement and are required to assess whether the preliminary distributions can be compared with theory or other experiments.
Authors: We acknowledge that the abstract currently provides no reference to these elements. Because the results are preliminary, the full set of cuts, corrections and uncertainties has not yet been finalized. We will revise the abstract to indicate that the analysis follows the procedures documented in our earlier isoscalar-target publications and that acceptance corrections together with systematic studies are in progress. This will give readers the necessary context without overstating the completeness of the present report. revision: partial
- Complete numerical values and tables for systematic uncertainties cannot be supplied at this stage because the full analysis of the entire 2016–2017 data set is still underway.
Circularity Check
Direct experimental measurement; no derivation or prediction chain present
full rationale
The paper reports measured transverse-momentum-dependent multiplicities extracted directly from COMPASS DIS data on a liquid-hydrogen target. No equations, ansätze, fitted parameters, or first-principles derivations are introduced whose outputs are then re-labeled as predictions. The sole methodological statement is that results are preliminary and based on a data subset; this is an empirical limitation, not a self-referential reduction of any claimed result to its own inputs. No self-citations, uniqueness theorems, or renamings of known patterns appear in a load-bearing role. The analysis is therefore self-contained against external benchmarks and receives the default non-circularity finding.
Axiom & Free-Parameter Ledger
axioms (1)
- standard math Standard definitions of DIS kinematic variables x, Q², z and P_hT² are used without modification.
discussion (0)
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