Recognition: no theorem link
FastJet user manual
Pith reviewed 2026-05-13 05:19 UTC · model grok-4.3
The pith
FastJet is a C++ package that provides efficient implementations of all widely used jet algorithms for particle physics.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
FastJet is a C++ package that provides a broad range of jet finding and analysis tools. It includes efficient native implementations of all widely used 2-to-1 sequential recombination jet algorithms for pp and e+e- collisions, as well as access to 3rd party jet algorithms through a plugin mechanism, including all currently used cone algorithms. FastJet also provides means to facilitate the manipulation of jet substructure, including some common boosted heavy-object taggers, as well as tools for estimation of pileup and underlying-event noise levels, determination of jet areas and subtraction or suppression of noise in jets.
What carries the argument
The FastJet C++ library, which unifies implementations of jet reconstruction algorithms and provides supporting analysis tools for substructure and background handling.
If this is right
- Users gain access to multiple jet algorithms through a consistent interface without needing separate codes for each.
- The plugin system allows incorporation of cone algorithms and other third-party methods.
- Substructure manipulation tools enable tagging of boosted heavy objects within jets.
- Noise estimation and subtraction features support cleaner jet measurements in high-pileup environments.
Where Pith is reading between the lines
- Switching between jet definitions within one framework could simplify comparisons of results from different algorithms.
- The area-based subtraction methods may allow more precise removal of underlying event contributions in complex collision events.
- Availability of these tools in a single package could reduce development time for new physics analyses.
Load-bearing premise
The package correctly and efficiently implements the described jet algorithms and analysis methods as claimed.
What would settle it
Running the package on benchmark events with known jet configurations and comparing outputs to independent calculations of the same algorithms would reveal any implementation errors.
read the original abstract
FastJet is a C++ package that provides a broad range of jet finding and analysis tools. It includes efficient native implementations of all widely used 2-to-1 sequential recombination jet algorithms for pp and e+e- collisions, as well as access to 3rd party jet algorithms through a plugin mechanism, including all currently used cone algorithms. FastJet also provides means to facilitate the manipulation of jet substructure, including some common boosted heavy-object taggers, as well as tools for estimation of pileup and underlying-event noise levels, determination of jet areas and subtraction or suppression of noise in jets.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript is the user manual for the FastJet C++ package. It describes the software's provision of efficient native implementations of all widely used 2-to-1 sequential recombination jet algorithms for pp and e+e- collisions, a plugin mechanism for third-party algorithms (including all current cone algorithms), tools to facilitate jet substructure manipulation (including common boosted heavy-object taggers), and utilities for estimating pileup and underlying-event noise levels, determining jet areas, and performing noise subtraction or suppression in jets.
Significance. As a comprehensive user manual for a widely adopted tool in high-energy physics, this document is significant for enabling correct and reproducible use of jet reconstruction algorithms in experimental analyses at facilities such as the LHC. The coverage of both standard clustering methods and advanced techniques like substructure tagging and area-based pileup mitigation directly supports ongoing research needs in jet physics.
minor comments (3)
- [Abstract] The abstract states that the package provides 'efficient native implementations' but does not include any performance benchmarks, timing comparisons, or verification tests; while not load-bearing for a user manual, adding a brief reference to such metrics (or to a companion paper) would strengthen user confidence in the efficiency claims.
- The document would benefit from an explicit statement of the software version number and release date to allow users to match the manual to their installed package.
- A dedicated section listing recommended citations for both the FastJet library and the manual itself would aid proper attribution in publications.
Simulated Author's Rebuttal
We thank the referee for their thorough review and positive recommendation to accept the manuscript. The referee's summary accurately captures the scope and purpose of the FastJet user manual.
Circularity Check
No significant circularity: user manual with no derivations or predictions
full rationale
The document is a software user manual whose content consists of factual descriptions of package capabilities, algorithm implementations, usage instructions, and API details. No physical derivations, quantitative predictions, fitted parameters, or mathematical claims are advanced. The central claim (provision of native sequential recombination algorithms, plugins, substructure tools, and pileup handling) is a direct statement of software features and does not rely on any internal chain of reasoning, self-citation, or ansatz that could reduce to its own inputs. As a self-contained documentation artifact, it has no load-bearing steps amenable to circularity analysis.
Axiom & Free-Parameter Ledger
Forward citations
Cited by 34 Pith papers
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Energy Correlators Within Jets in Transversely Polarized Proton-Proton Collisions at $\sqrt{s} = 200$ GeV
First measurement of energy correlators in jets from transversely polarized pp collisions at 200 GeV shows sizable spin asymmetries for pions that provide sensitivity to nucleon transversity with reduced fragmentation...
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Probing Boosted Light Scalars in the Type-I 2HDM
Boosted light scalars decaying to b b-bar in Type-I 2HDM can be tagged as double-b fat-jets and used with SM gauge bosons to probe heavy scalars up to 540 GeV at the HL-LHC for masses 30-70 GeV.
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Measurement of jet photoproduction in ultra-peripheral Pb+Pb collisions without nuclear breakup at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV with the ATLAS detector
First measurement of γ+IP→jets cross-sections in 0n0n ultra-peripheral Pb+Pb collisions at 5.02 TeV, achieved by statistically separating photon-pomeron, photon-photon, and peripheral photonuclear contributions via te...
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Probing compressed triplet scalars with ISR jets and soft leptons at the LHC
A cut-and-count analysis exploiting ISR jets and soft leptons can reach discovery sensitivity for compressed triplet scalars with 1-30 GeV splittings at 3000 fb^{-1}.
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NLO QCD and parton-shower effects for Higgs-boson production in association with a hard photon via vector-boson fusion
NLO QCD plus parton-shower matched implementation for VBF Higgs plus photon production, with studies showing small shower effects on Higgs observables and larger effects on sub-leading jets.
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Composite top partners in exotic colour representations
Colour-sextet top partners in composite Higgs models are excluded up to 2-2.5 TeV by current LHC data via top-rich decays, with HL-LHC reach near 3 TeV.
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Observation of impact parameter dependent modifications of nuclear parton distributions in photonuclear Pb+Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV with the ATLAS detector
ATLAS reports a 6 sigma observation that nuclear parton distribution modifications in photonuclear Pb+Pb collisions depend on impact parameter, shown by differing cross-section shapes versus x+ with and without forwar...
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How Invisible: Regressing The Key Model Parameter for Semi-visible Jet Searches
A regression model reconstructs the key parameter r_inv for semi-visible jets at higher precision than prior analytical methods and may unify s- and t-channel production searches.
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Low-Multiplicity Jets as Probes of GeV-Scale Light-Quark-Coupled Particles
A proposed LHC search using low-multiplicity jets plus a photon can extend sensitivity to GeV-scale particles that couple to light quarks.
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A new approach to long-lived particle detection at hadron colliders: the $\textsf{DELIGHT-SHIELD}$ concept
DELIGHT-SHIELD uses a dedicated shield followed by tracking to suppress hadronic and electromagnetic backgrounds by up to seven orders of magnitude, reaching branching ratio sensitivity of O(10^{-9}) for h to phi phi ...
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Measurement of jet quenching in O+O collisions at $\sqrt{s_\mathrm{NN}}=200$ GeV by the STAR experiment at RHIC
STAR reports 20% suppression of recoiling hadrons and jets in high-event-activity O+O collisions at 200 GeV, with a measured 0.7 GeV/c pT shift for large-radius jets, providing evidence for jet quenching in small systems.
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Probing Higgs and Top Interactions through the Muon Lens at multi-TeV Muon Colliders
A 10 TeV muon collider could improve existing bounds on muon-Higgs-gauge and muon-top interactions by up to an order of magnitude over current limits and FCC-ee projections.
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Dijet invariant mass of charged-particle jets in pp and p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV
The first measurement of charged-particle dijet invariant mass spectra shows no significant nuclear modification in p-Pb collisions at low masses.
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Search for pair production of additional neutral scalars within the Inert Doublet Model in a final state with two electrons or two muons in proton-proton collisions at $\sqrt{s}$ = 13 TeV and 13.6 TeV
No significant excess found; new exclusion limits reach m_H = 108 GeV for m_H - m_A = 78 GeV in the Inert Doublet Model.
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Time-dependent signals of new physics at the LHC
Incorporating timing information from time-dependent new physics signals can improve LHC search sensitivity by up to a factor of two compared to standard time-invariant analyses.
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Probing anomalous quartic gauge couplings via vector boson scattering at the same-sign muon collider
Projections show the μTRISTAN same-sign muon collider can significantly improve bounds on anomalous quartic gauge couplings via vector boson scattering in multiple final states at 2 and 6 TeV.
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Kitchen Sink Anomaly Detection
A combined kitchen sink observable set of Energy Flow Polynomials and subjettiness variables outperforms standard baselines in sensitivity to a wide range of resonant signals, with new public benchmarks released and a...
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Quantum Tomography and Entanglement in Semi-Leptonic $h\to VV^*$ Decays at Higher Orders
Semi-leptonic h to VV* decays retain an effective two-qutrit description for quantum tomography and entanglement after including finite fermion masses and NLO corrections.
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Logarithmic EW corrections at two-loop
Implementation of NNLO EW NLL corrections in OpenLoops for massless fermions and transversely polarized vector bosons, validated against analytic results and applied to representative LHC processes.
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A dynamical implementation of colour coherence for quenched jets in JEWEL
A per-interaction resolution check in JEWEL dynamically breaks colour coherence, suppressing hard radiation and reducing scattering rates in quenched jets.
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DELPHES 3, A modular framework for fast simulation of a generic collider experiment
DELPHES 3 delivers a modular fast-simulation framework with particle-flow and pile-up features for reconstructing physics objects in collider detector studies.
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Constraints on anomalous Higgs boson couplings to vector bosons and fermions using the $\gamma\gamma$ final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV
Updated constraints from the full Run 2 dataset show no evidence for anomalous Higgs couplings in gluon fusion, vector boson fusion, and associated production modes decaying to two photons.
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Search for charginos and neutralinos with $B-L$ $R$-parity violating decays in $\sqrt{s}=13$ TeV and $13.6$ TeV $pp$ collisions with the ATLAS detector
No evidence for charginos and neutralinos in R-parity violating Higgs-decay channels; masses 150-1100 GeV excluded at 95% CL assuming equal lepton branching fractions.
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Phenomenology of electroweak spin-1 resonances
Composite Higgs models with SU(2)_L × SU(2)_R predict spin-1 resonances mixing with electroweak bosons that remain viable at the LHC down to masses of about 1.5 TeV.
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Search for quantum black holes in lepton+jet final states using proton-proton collisions at $\sqrt{s}=13.6$ TeV with the ATLAS detector
No significant excess of high-mass lepton+jet events is observed in 164 fb^{-1} of 13.6 TeV pp collisions, setting 95% CL upper limits on quantum black hole production cross-section times branching ratio that reach a ...
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Sensitivity to top-quark FCNC interactions at future muon colliders
A 10 TeV muon collider with 10 ab^{-1} could reach O(10^{-3}) sensitivity on top-quark FCNC couplings, improving current ATLAS/CMS bounds by more than an order of magnitude.
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An Introduction to PYTHIA 8.2
PYTHIA 8.2 is a mature C++ event generator that combines hard processes, parton showers, multiparton interactions, and string fragmentation into a complete simulation framework for high-energy collisions.
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Search for new physics in triple boson production in proton-proton collisions at $\sqrt{s}$ = 13 TeV using the effective field theory approach
No excess in VVV production; bounds set on c_W/Λ² (-0.13 to 0.12 TeV^{-2}) and c_Hq3/Λ² (-0.24 to 0.21 TeV^{-2}) at 95% CL.
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Prospects for Measuring $H\to \rm{invisble}$ at the FCCee
FCC-ee at 240 GeV with 10.8 ab^{-1} could set a 95% CL upper limit of 0.15% on the branching ratio of Higgs to invisible particles.
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Possibility of Probing an Extra Higgs Boson at the Compact Linear Collider
CLIC can probe an additional neutral Higgs boson H in the Two Higgs Doublet Model through the process e+e- to H nu nu-bar with H decaying to WW in the dilepton channel.
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Probing the electron Yukawa coupling via resonant Higgs boson production at FCC-ee via $e^+e^- \to H \to WW^*$ in lepton-plus-jets final states
Simulation projects 2.0 sigma significance for resonant Higgs production at FCC-ee, yielding an upper limit of kappa_e less than or equal to 1.35 at 95% CL on the electron Yukawa coupling modifier with 10 ab inverse l...
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Doubly charged Higgs production within the Higgs triplet model at future electron-positron colliders
CLIC offers superior discovery potential for doubly charged Higgs bosons in the Higgs triplet model compared to HL-LHC, reaching masses up to 1.2 TeV in gauge-like scenarios and high significance in Yukawa-like region...
- Looking inside jets: an introduction to jet substructure and boosted-object phenomenology
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discussion (0)
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