# ============================================================================ # P07 — Scalar leptoquark $m_{ej}$ resonance at the 13 TeV LHC (LUXlep PDF) # ---------------------------------------------------------------------------- # Adapts ColliderAgent paper-reproduction prompt: # /home/shiqiu/ColliderAgent/paper-reproduction/2005.06475/prompt_figure_2.md # Source: arXiv:2005.06475 — single resonant LQ production via lepton-PDF # (LUXlep) inside the proton, $pp \to \mathrm{LQ} \to ej$ resonance peak. # ============================================================================ id: P07 title: "Reproducing the $m_{ej}$ resonance in $pp \\to \\mathrm{LQ} \\to ej$ via the LUXlep proton lepton PDF" arxiv_id: "2005.06475" venue: "ARC-Bench Physics 2026" paper_asset: null synthesis: | Reproducing the LHC sensitivity to a scalar leptoquark in the $pp \to \mathrm{LQ} \to ej$ channel as a benchmark of the agent's ability to assemble a full Lagrangian -> MC -> shower -> detector -> analysis pipeline using a non-trivial PDF (LUXlep, with electrons inside the proton). The Lagrangian $\mathcal{L} = \lambda_{eu}\,\mathrm{LQ}_{eu}\,e_R^T i\sigma^2 u_R + \mathrm{h.c.}$ describes an $SU(2)_L$-singlet, color-triplet, $Q=-1/3$ scalar leptoquark coupling to a right-handed lepton-quark pair. The diagnostic observable is the reconstructed invariant mass $m_{ej}$ of the leading electron and leading jet, peaked at the input $M_\mathrm{LQ}=3$ TeV with $\Gamma_\mathrm{LQ}=60$ GeV after Pythia8 + Delphes ATLAS detector smearing. A credible study (a) implements the scalar-LQ Lagrangian (FeynRules .fr + UFO), (b) generates 100k events at $\sqrt{s}=13$ TeV with the LUXlep PDF (proton content redefined to include leptons + photon) and generation cuts $p_T(\ell, j) > 500$ GeV, $|\eta| < 2.5$, (c) applies the Pythia8 lepton-to-photon workaround (replace initial-state leptons with photons in the LHE; set Check:event=off; shower; Delphes ATLAS card with anti-$k_T$ R=0.4 jets; LHCO output), (d) selects events with exactly one $e$ ($p_T>500$ GeV, $|\eta|<2.5$), one $j$ ($p_T>500$ GeV, $|\eta|<2.5$), $E_T^\mathrm{miss} < 50$ GeV, lepton veto, jet veto, (e) histograms $m_{ej}$ in 100 GeV bins from 0 to 5000 GeV weighted by $\sigma\mathcal{L}/N_\mathrm{gen}$ at $\mathcal{L}=100$ fb$^{-1}$, and (f) plots on log-y $[10^{-3}, 5\times 10^2]$ events/bin over [1000, 5000] GeV. Research question: *does the agent reproduce the scalar-LQ resonance peak at $m_{ej} \approx 3$ TeV from Figure 2 of arXiv:2005.06475?* hypotheses: - id: H1 statement: "Reconstructed $m_{ej}$ peaks within $\\pm 5\\%$ of the input $M_\\mathrm{LQ}=3000$ GeV after Pythia8+Delphes smearing (i.e., peak in [2850, 3150] GeV)." measurable: true - id: H2 statement: "The generation-level $p_T(\\ell, j) > 500$ GeV cut yields $\\geq 50\\%$ acceptance for the benchmark $M_\\mathrm{LQ}=3$ TeV signal." measurable: true - id: H3 statement: "Total event count in the [2.5, 3.5] TeV $m_{ej}$ window at $\\mathcal{L} = 100$ fb$^{-1}$ matches the published value within $\\pm 30\\%$." measurable: true experiment_design: research_question: "Does the agent reproduce the $m_{ej}$ invariant-mass distribution for $pp \\to \\mathrm{LQ} \\to ej$ at $\\sqrt{s}=13$ TeV with LUXlep PDF and $M_\\mathrm{LQ}=3$ TeV (Figure 2 of arXiv:2005.06475)?" conditions: - name: "lq_3tev_lambda1" description: "Scalar LQ at $M_\\mathrm{LQ}=3000$ GeV, $\\Gamma_\\mathrm{LQ}=60$ GeV, $\\lambda_{eu}=1$, 100k events at $\\sqrt{s}=13$ TeV, LUXlep PDF, $p_T > 500$ GeV gen cuts, Pythia8 + Delphes ATLAS, LHCO output." - name: "lq_2tev_check" description: "Cross-check at $M_\\mathrm{LQ}=2000$ GeV with $\\lambda_{eu}=1$, same setup; verify that $m_{ej}$ peak shifts to 2 TeV." baselines: - "Background-only sanity check: $\\lambda_{eu}=0$ (LQ decoupled) should produce zero $m_{ej}$ events above the gen-level cut" metrics: - name: "peak_position_gev" direction: "match_reference" description: "Bin-center of the maximum of the reconstructed $m_{ej}$ histogram for the 3 TeV signal." - name: "acceptance_pt500" direction: "match_reference" description: "Fraction of generated events with both lepton and jet $p_T > 500$ GeV at $M_\\mathrm{LQ}=3$ TeV." - name: "integrated_yield_in_window" direction: "match_reference" description: "Sum of weighted events in $m_{ej} \\in [2500, 3500]$ GeV at $\\mathcal{L}=100$ fb$^{-1}$." datasets: - process_id: "pp_to_LQ_to_ej_LUXlep" sqrt_s_TeV: 13 description: "Single resonant scalar leptoquark production via lepton-quark fusion using LUXlep proton PDF." compute_requirements: gpu_required: false estimated_wall_clock_sec: 3600 rubric_path: "experiments/arc_bench/config/physics/rubrics/P07.json" # --------------------------------------------------------------------------- # Agent-mode requirements (consumed by researchclaw.pipeline.requirements_judge # at stage 15 RESEARCH_DECISION). Schema mirrors B01.yaml: # id — stable identifier # type — advisory hint to the LLM judge (numeric | artifact | discussion) # description — natural-language statement of what must be true post-run # must_pass — true → unmet ⇒ rerun (1 retry max); false → optional # # The five generic must_pass items apply uniformly across P01-P10; the sixth # is topic-specific (mirrors this manifest's H1). The two must_pass=false # items reward mechanistic interpretation and MC-reproducibility metadata # without blocking proceed-vs-rerun on them. # --------------------------------------------------------------------------- requirements: - id: req_results_json type: artifact description: >- A canonical results.json file exists at the workspace root with at least the keys: primary_metric (number), metric_key (string), metrics (object with numeric keys), hypotheses (object with h1/h2/h3 entries each carrying a `supported` boolean), summary (non-empty string). must_pass: true - id: req_metrics_numeric type: numeric description: >- results.json metrics MUST contain at least 3 numeric (non-null, finite) values directly relevant to the headline physics observable named in the experiment_design.metrics list above — these are the numbers the paper will report in its Results section. must_pass: true - id: req_hypotheses_supported_flags type: discussion description: >- results.json hypotheses.h1/h2/h3 each MUST have an explicit `supported` boolean AND a `details` string ≥ 40 characters quoting the numerical evidence (specific values + their source artifact) used to reach the verdict. must_pass: true - id: req_publication_figure type: artifact description: >- At least one publication-quality figure file (PDF or PNG, ≥150 DPI for raster) exists under figures/ or output/figures/ with axes labeled in physical units (GeV / pb / fb / dimensionless) and a legend if multiple series are plotted. The figure must directly support a hypothesis verdict. must_pass: true - id: req_model_implementation type: artifact description: >- The BSM Lagrangian is implemented either as a FeynRules .fr file (models/*.fr) with a matching UFO directory (models/*_UFO/ containing at least particles.py, parameters.py, couplings.py, vertices.py), OR as analytic Python code that explicitly computes the cross sections from the Lagrangian terms. A pure SM baseline with no BSM piece is NOT sufficient. must_pass: true - id: req_mej_peak_position type: numeric description: >- results.json metrics MUST report the reconstructed m_ej peak position (after Pythia8+Delphes smearing) in the interval [2850, 3150] GeV (input M_LQ=3 TeV ±5%). must_pass: true - id: req_mechanistic_writeup type: discussion description: >- The summary or structured_results section provides a one-paragraph mechanistic interpretation of WHY the headline observable comes out the way it does (which interference / propagator structure / cut effect drives the result). Nice-to-have, not blocking proceed. must_pass: false - id: req_mc_reproducibility type: discussion description: >- results.json or a sibling reproducibility section names: (a) the MadGraph5_aMC@NLO version, (b) the PDF set used (if applicable), (c) at least one explicit random seed. Required for full reproducibility but not for scientific correctness. must_pass: false