def
definition
amplitudeS2
show as:
view math explainer →
open explainer
Generate a durable explainer page for this declaration.
open lean source
IndisputableMonolith.StandardModel.LongitudinalVectorScattering on GitHub at line 67.
browse module
All declarations in this module, on Recognition.
explainer page
depends on
used by
formal source
64
65 The Higgs cancellation is the statement that for the SM scalar
66 coupling, `a_gauge + a_scalar = 0`. -/
67def amplitudeS2 (a_gauge a_scalar v s : ℝ) : ℝ :=
68 (a_gauge + a_scalar) * s ^ 2 / v ^ 4
69
70/-- Gauge-only amplitude (no scalar contribution): the dangerous
71 `s²/v⁴` growth. -/
72def amplitudeGaugeOnly (a_gauge v s : ℝ) : ℝ :=
73 a_gauge * s ^ 2 / v ^ 4
74
75/-- Scalar-only amplitude. -/
76def amplitudeScalarOnly (a_scalar v s : ℝ) : ℝ :=
77 a_scalar * s ^ 2 / v ^ 4
78
79/-- The total amplitude is the sum of gauge and scalar contributions. -/
80theorem amplitude_decomposition
81 (a_gauge a_scalar v s : ℝ) (hv : v ≠ 0) :
82 amplitudeS2 a_gauge a_scalar v s
83 = amplitudeGaugeOnly a_gauge v s + amplitudeScalarOnly a_scalar v s := by
84 unfold amplitudeS2 amplitudeGaugeOnly amplitudeScalarOnly
85 have hv4 : v ^ 4 ≠ 0 := pow_ne_zero 4 hv
86 field_simp
87
88/-! ## §2. The Cancellation Condition -/
89
90/-- The high-energy cancellation condition: gauge and scalar exchange
91 sum to zero at the leading `s²/v⁴` order. -/
92def CancellationCondition (a_gauge a_scalar : ℝ) : Prop :=
93 a_gauge + a_scalar = 0
94
95/-- When the cancellation condition holds, the leading `s²` term vanishes
96 identically. -/
97theorem amplitude_vanishes_under_cancellation