# ============================================================================ # P03 — B-L Z' exclusion contours at LHC Run 1 dilepton search # ---------------------------------------------------------------------------- # Adapts ColliderAgent paper-reproduction prompt: # /home/shiqiu/ColliderAgent/paper-reproduction/1605.02910/prompt_figure_1.md # Source: arXiv:1605.02910 — kinetic-mixing B-L Z' phenomenology, three-panel # exclusion contours in the $(\tilde g, g_1')$ plane at $\sqrt{s}=8$ TeV. # ============================================================================ id: P03 title: "Reproducing 8 TeV LHC dilepton exclusion contours for a B-L Z' boson with kinetic mixing" arxiv_id: "1605.02910" venue: "ARC-Bench Physics 2026" paper_asset: null synthesis: | Reproducing the LHC Run 1 sensitivity to a B-L gauge boson Z' with kinetic mixing as a benchmark of the agent's ability to combine MC parameter scans with an analytic statistical recast. The model has a Z' coupling to SM fermions via a left/right combination $C_{f,L/R}(\tilde g, g_1', M_{Z'})$ where $g_1'$ is the B-L gauge coupling, $\tilde g$ is the kinetic mixing, and the production cross section is the exact quadratic form $\sigma(pp \to Z') = A g_1'^2 + B g_1' \tilde g + C \tilde g^2$ — so three runs per mass point determine $(A,B,C)$ for the entire $(\tilde g, g_1')$ plane. The diagnostic observable is the three-panel exclusion contour at $\mathrm{Sig}\equiv 2(\sqrt{S+B}-\sqrt B) = 2$ for $M_{Z'} \in \{2.0, 2.5, 3.0\}$ TeV at $\mathcal{L} = 20$ fb$^{-1}$. A credible study (a) implements the kinetic-mixing B-L Lagrangian and $C_{f,L/R}$ couplings, (b) runs the 9 signal MadGraph runs (3 mass points x 3 coupling points) plus 3 SM Drell-Yan background runs with $m_{\ell\ell} > 0.9 M_{Z'}$ generator cut, (c) computes the analytic $Z' \to e^+e^- + \mu^+\mu^-$ branching ratio including 3 degenerate heavy Majorana neutrinos $m_{\nu_h}=95$ GeV, (d) applies the published NNLO k-factors $k\in\{1.35,1.40,1.50\}$ and acceptance $\epsilon_\mathrm{acc}=0.6$, (e) solves the $\mathrm{Sig}=2$ equation on a 2D grid in $(\tilde g, g_1')$, and (f) plots three side-by-side contours. Research question: *does the agent reproduce the three-panel $(\tilde g, g_1')$ exclusion contours at $M_{Z'}=2.0, 2.5, 3.0$ TeV from Figure 1 of arXiv:1605.02910?* hypotheses: - id: H1 statement: "For the $M_{Z'}=2$ TeV panel, the exclusion contour crosses the $\\tilde g = 0$ axis at $g_1' \\in [0.10, 0.20]$ (matching the published value within 30%)." measurable: true - id: H2 statement: "The $(A, B, C)$ quadratic coefficients extracted at $M_{Z'}=2$ TeV satisfy $A > 0$ and $|B| \\le 4\\sqrt{AC}$ (positivity of the cross section over the full parameter plane)." measurable: true - id: H3 statement: "The maximum reach in $g_1'$ at $\\tilde g = 0$ degrades by at least a factor of 2 going from $M_{Z'}=2$ TeV to $M_{Z'}=3$ TeV, reflecting the PDF suppression at high mass." measurable: true experiment_design: research_question: "Does the agent reproduce the three-panel $(\\tilde g, g_1')$ 2$\\sigma$ exclusion contours at $M_{Z'}=2.0, 2.5, 3.0$ TeV from the LHC Run 1 dilepton search at $\\sqrt{s}=8$ TeV with $\\mathcal{L}=20$ fb$^{-1}$ (Figure 1 of arXiv:1605.02910)?" conditions: - name: "mzp_2tev" description: "$M_{Z'}=2$ TeV: 3 signal runs at $(g_1', \\tilde g) \\in \\{(0.10, 0), (0.10, -0.10), (0.15, -0.05)\\}$." - name: "mzp_2p5tev" description: "$M_{Z'}=2.5$ TeV: 3 signal runs at the same three $(g_1', \\tilde g)$ points." - name: "mzp_3tev" description: "$M_{Z'}=3$ TeV: 3 signal runs at $(g_1', \\tilde g) \\in \\{(0.30, 0), (0.30, -0.30), (0.50, -0.60)\\}$." baselines: - "SM Drell-Yan $pp \\to \\ell^+\\ell^-$ at $\\sqrt{s}=8$ TeV with generator-level cut $m_{\\ell\\ell} > 0.9 M_{Z'}$, one per mass point" metrics: - name: "exclusion_g1p_at_kinmix0" direction: "match_reference" description: "Value of $g_1'$ at which the $\\mathrm{Sig}=2$ contour crosses $\\tilde g = 0$, per mass point." - name: "quadratic_coefficients_ABC" direction: "match_reference" description: "$(A, B, C)$ extracted from the 3 signal runs per mass; positive-definite check." - name: "br_zprime_to_dilepton" direction: "match_reference" description: "Analytic $\\mathrm{BR}(Z' \\to e^+e^-+\\mu^+\\mu^-)$ at the three benchmark masses." datasets: - process_id: "pp_to_Zprime_BL_kinmix" sqrt_s_TeV: 8 description: "$pp \\to Z'$ with kinetic-mixing B-L Z' at the LHC, dilepton final state. Background: SM Drell-Yan with $m_{\\ell\\ell}$ cut." compute_requirements: gpu_required: false estimated_wall_clock_sec: 3600 rubric_path: "experiments/arc_bench/config/physics/rubrics/P03.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_g1prime_threshold type: numeric description: >- results.json metrics MUST report the g1' coordinate where the 2σ exclusion contour at M_Z'=2 TeV crosses the g̃=0 axis, in the interval [0.07, 0.26] (i.e. published [0.10, 0.20] ±30%). 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