{
  "format": "sandboxphysics-bbn-replay-input",
  "formatVersion": 1,
  "units": {
    "eta10": "10^10 n_b / n_gamma today",
    "deltaNeff": "extra relativistic species counted as neutrino flavours, on top of the model's 3",
    "neutronLifetime": "s"
  },
  "solver": {"steps": 2000, "labSteps": 1000, "convergenceSteps": [250, 500, 1000, 2000, 4000]},
  "cases": [
    {"id": "standard-cmb-baryons", "eta10": 6.12, "deltaNeff": 0.0, "neutronLifetime": 878.4},
    {"id": "baryon-poor", "eta10": 2.0, "deltaNeff": 0.0, "neutronLifetime": 878.4},
    {"id": "baryon-rich", "eta10": 15.0, "deltaNeff": 0.0, "neutronLifetime": 878.4},
    {"id": "extra-radiation", "eta10": 6.12, "deltaNeff": 1.5, "neutronLifetime": 878.4},
    {"id": "missing-radiation", "eta10": 6.12, "deltaNeff": -1.0, "neutronLifetime": 878.4}
  ],
  "benchmarks": {
    "primatBornRow": {
      "source": "Pitrou et al., arXiv:1801.08023v3, Table V row 'Born' (Omega_b h^2 = 0.02225, tau_n = 879.5 s, N_nu = 3)",
      "eta10": 6.0913, "deltaNeff": 0.0, "neutronLifetime": 879.5,
      "heliumMassFraction": 0.24262, "deuteriumToHydrogen": 2.423e-5,
      "helium3ToHydrogen": 1.069e-5, "lithium7ToHydrogen": 5.635e-10,
      "toleranceHeliumRelative": 0.003
    },
    "serpico2004Tables": {
      "source": "Serpico et al., arXiv:astro-ph/0408076v3, Tables 3 and 4 (tau_n = 885.7 s, eta10 = 273.49 omega_b / (1 - 0.007 Y_p))",
      "neutronLifetime": 885.7,
      "rows": [
        {"omegaB": 0.022, "deuteriumToHydrogen": 2.63e-5, "helium3ToHydrogen": 1.03e-5, "lithium7ToHydrogen": 4.5e-10, "heliumMassFraction": 0.2477},
        {"omegaB": 0.023, "deuteriumToHydrogen": 2.44e-5, "helium3ToHydrogen": 1.01e-5, "lithium7ToHydrogen": 4.9e-10, "heliumMassFraction": 0.2481},
        {"omegaB": 0.024, "deuteriumToHydrogen": 2.28e-5, "helium3ToHydrogen": 0.98e-5, "lithium7ToHydrogen": 5.3e-10, "heliumMassFraction": 0.2485}
      ],
      "toleranceRelative": {"deuteriumToHydrogen": 0.04, "helium3ToHydrogen": 0.05, "lithium7ToHydrogen": 0.08}
    },
    "fields2020Sensitivities": {
      "source": "Fields et al., arXiv:1912.01132v1, Table II, d ln X / d ln p at eta10 = 6.129, tau_n = 879.4 s",
      "eta10": 6.129, "neutronLifetime": 879.4,
      "order": ["heliumMassFraction", "deuteriumToHydrogen", "helium3ToHydrogen", "lithium7ToHydrogen"],
      "rows": {
        "eta": [0.039, -1.597, -0.583, 2.094],
        "N_nu": [0.163, 0.396, 0.139, -0.280],
        "G_N": [0.357, 0.952, 0.335, -0.719],
        "neutron_lifetime": [0.729, 0.409, 0.144, 0.434],
        "p(n,g)d": [0.005, -0.193, 0.087, 1.323],
        "3He(n,p)t": [0.000, 0.023, -0.169, -0.267],
        "7Be(n,p)7Li": [0.000, 0.000, 0.000, -0.707],
        "d(p,g)3He": [0.000, -0.315, 0.376, 0.589],
        "7Li(p,a)4He": [0.000, 0.000, 0.000, -0.055],
        "t(a,g)7Li": [0.000, 0.000, 0.000, 0.029],
        "3He(a,g)7Be": [0.000, 0.000, 0.000, 0.964],
        "d(d,n)3He": [0.006, -0.529, 0.213, 0.696],
        "d(d,p)t": [0.005, -0.470, -0.265, 0.064],
        "t(d,n)4He": [0.000, 0.000, -0.009, -0.023],
        "3He(d,p)4He": [0.000, -0.012, -0.763, -0.754]
      },
      "toleranceAbsolute": 0.06
    },
    "pdgHeliumPerNeutrino": {
      "source": "Fields, Molaro and Sarkar, PDG 2025 Sec. 24.4: Delta Y_p ~= 0.013 Delta N_nu",
      "slope": 0.013, "toleranceAbsolute": 0.0015
    },
    "classPrimatHeliumPerNeutrino": {
      "source": "CLASS external/bbn/sBBN_2025_primat.dat (PRIMAT, tau_n = 878.4 s), Y_He at omega_b = 0.0224 for Delta N = -1, 0, +1",
      "omegaB": 0.0224, "heliumMinusOne": 0.231266, "heliumZero": 0.245674, "heliumPlusOne": 0.258157,
      "toleranceSlopeRelative": 0.08
    }
  },
  "monteCarlo": {"samples": 200, "seed": 20261112, "eta10": 6.12, "neutronLifetime": 878.4}
}