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mass_evolution_exp
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IndisputableMonolith.Physics.RunningCouplings on GitHub at line 244.
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241def mass_anomalous_dim : ℝ := 8
242
243/-- Mass evolution exponent γ₀/(2b₀) for `n_f` active flavors. -/
244noncomputable def mass_evolution_exp (n_f : ℕ) : ℝ :=
245 mass_anomalous_dim / (2 * b0_qcd n_f)
246
247theorem mass_anomalous_dim_pos : 0 < mass_anomalous_dim := by
248 unfold mass_anomalous_dim; norm_num
249
250theorem mass_evolution_exp_pos (n_f : ℕ) (h : n_f ≤ 16) :
251 0 < mass_evolution_exp n_f := by
252 unfold mass_evolution_exp
253 exact div_pos mass_anomalous_dim_pos
254 (mul_pos (by norm_num) (asymptotic_freedom_criterion n_f h))
255
256/-- Concrete mass evolution exponents for physical n_f values. -/
257theorem mass_evo_exp_nf3 : mass_evolution_exp 3 = 8 / 18 := by
258 unfold mass_evolution_exp mass_anomalous_dim b0_qcd; norm_num
259theorem mass_evo_exp_nf4 : mass_evolution_exp 4 = 8 / (50 / 3) := by
260 unfold mass_evolution_exp mass_anomalous_dim b0_qcd; norm_num
261theorem mass_evo_exp_nf5 : mass_evolution_exp 5 = 8 / (46 / 3) := by
262 unfold mass_evolution_exp mass_anomalous_dim b0_qcd; norm_num
263theorem mass_evo_exp_nf6 : mass_evolution_exp 6 = 8 / 14 := by
264 unfold mass_evolution_exp mass_anomalous_dim b0_qcd; norm_num
265
266/-- LO QCD running mass at scale μ₂ given reference mass at μ₁.
267 Uses real-valued power `rpow` since the exponent γ₀/(2b₀) is non-integer. -/
268noncomputable def running_mass (m_ref α_s_ref α_s_target : ℝ) (n_f : ℕ) : ℝ :=
269 m_ref * (α_s_target / α_s_ref) ^ (mass_evolution_exp n_f)
270
271/-- **Mass ratios within a sector are RG-invariant at LO** when both masses
272 are evolved from the same reference scale with the same α_s values. -/
273theorem mass_ratio_rg_invariant (m1 m2 α_s_ref α_s_target : ℝ) (n_f : ℕ)
274 (hr : (α_s_target / α_s_ref) ^ (mass_evolution_exp n_f) ≠ 0) :