# ============================================================================ # P02 — Heavy Majorana neutrino production at the LHC ($pp \to \mu^\pm N$) # ---------------------------------------------------------------------------- # Adapts ColliderAgent paper-reproduction prompt: # /home/shiqiu/ColliderAgent/paper-reproduction/1308.2209/prompt_figure_3.md # Source: arXiv:1308.2209 — heavy Majorana neutrino searches at the LHC, # extending the SM with a single right-handed singlet $N$ that mixes with # the muon flavor via $V_{\mu N}$. # ============================================================================ id: P02 title: "Reproducing $pp \\to \\mu^\\pm N$ cross section vs heavy-Majorana-neutrino mass at $\\sqrt{s} = 7, 8, 14$ TeV" arxiv_id: "1308.2209" venue: "ARC-Bench Physics 2026" paper_asset: null synthesis: | Reproducing the LHC sensitivity to a single heavy Majorana neutrino $N$ in the muon channel as a benchmark of the agent's ability to assemble a hadron-collider Lagrangian -> MC -> analysis pipeline. The BSM extension adds a right-handed singlet $N$ mixing with $\nu_\mu$ via the dimensionless real parameter $V_{\mu N}$, so the relevant interaction is $\mathcal{L}_N \supset -(g_2/\sqrt{2})\,V_{\mu N}\,(\bar\mu\gamma^\mu P_L N)\,W^-_\mu + (\text{NC term}) + \text{h.c.}$ The diagnostic observable is the $W^*$-mediated cross section $\sigma(pp \to \mu^\pm N)$ scanned over $m_N \in \{100, 200, \ldots, 1000\}$ GeV with $|V_{\mu N}|=1$, at three LHC energies $\sqrt{s} \in \{7, 8, 14\}$ TeV with the CTEQ6L PDF. A credible study (a) implements the heavy-Majorana-neutrino Lagrangian (FeynRules .fr or analytic UFO modification), (b) sets up MadGraph runs for the 30 (mass, energy) cells with the CTEQ6L PDF, (c) extracts the cross section per cell, and (d) plots three side-by-side panels of $\sigma(m_N)$ on a log-y axis over $[100,1000]$ GeV vs $[0.1, 4\times 10^4]$ fb. Research question: *does the agent reproduce the steep PDF-driven fall-off of $\sigma(pp \to \mu^\pm N)$ with $m_N$ and the correct ordering between $\sqrt{s}=7$, 8, and 14 TeV predicted by arXiv:1308.2209 Fig. 3?* hypotheses: - id: H1 statement: "At $m_N = 200$ GeV and $\\sqrt{s}=14$ TeV, $\\sigma(pp \\to \\mu^\\pm N)$ falls within $\\pm 30\\%$ of the published reference value." measurable: true - id: H2 statement: "Cross-section ordering $\\sigma(14\\,\\mathrm{TeV}) > \\sigma(8\\,\\mathrm{TeV}) > \\sigma(7\\,\\mathrm{TeV})$ holds at every mass point, with the 14/7 ratio at $m_N = 500$ GeV in $[5, 30]$." measurable: true - id: H3 statement: "$\\sigma(m_N)$ falls by at least 2 orders of magnitude between $m_N = 100$ GeV and $m_N = 1000$ GeV at every LHC energy." measurable: true experiment_design: research_question: "Does the agent reproduce the cross-section curves for $pp \\to \\mu^\\pm N$ as a function of the heavy-Majorana-neutrino mass at the 7, 8, and 14 TeV LHC, matching Figure 3 of arXiv:1308.2209?" conditions: - name: "lhc_7tev" description: "$pp$ collisions at $\\sqrt{s}=7$ TeV with CTEQ6L PDF, mass scan $m_N \\in \\{100, 200, 300, 400, 500, 600, 700, 800, 900, 1000\\}$ GeV, $|V_{\\mu N}|=1$." - name: "lhc_8tev" description: "Same setup at $\\sqrt{s}=8$ TeV (LHC Run 1 final dataset energy)." - name: "lhc_14tev" description: "Same setup at $\\sqrt{s}=14$ TeV (HL-LHC design)." baselines: - "Charged-current SM $pp \\to \\mu \\nu_\\mu$ (W production) cross check at the same energies" metrics: - name: "cross_section_fb" direction: "match_reference" description: "Total $\\sigma(pp \\to \\mu^\\pm N)$ in fb at each (mass, energy) cell." - name: "energy_ratio_14_to_7" direction: "match_reference" description: "$\\sigma(14\\,\\mathrm{TeV})/\\sigma(7\\,\\mathrm{TeV})$ at $m_N = 500$ GeV." - name: "mass_dropoff_factor" direction: "match_reference" description: "$\\sigma(m_N=100)/\\sigma(m_N=1000)$ at each $\\sqrt{s}$." datasets: - process_id: "pp_to_muN_via_Wstar" sqrt_s_TeV: 14 description: "$pp \\to \\mu^\\pm N$ via $W^*$ at the LHC (CTEQ6L PDF). Three sub-samples for $\\sqrt{s} \\in \\{7,8,14\\}$ TeV." compute_requirements: gpu_required: false estimated_wall_clock_sec: 3600 rubric_path: "experiments/arc_bench/config/physics/rubrics/P02.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_xsec_at_mN_200 type: numeric description: >- results.json metrics MUST report a numeric `sigma_pp_to_muN_at_mN200_14TeV_fb` (or equivalent) within ±30% of the published reference value at m_N=200 GeV, √s=14 TeV. 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