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r_min
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IndisputableMonolith.Nuclear.QCDToNuclearBridge on GitHub at line 113.
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110/-! ## Saturation Properties -/
111
112/-- Nuclear saturation radius r_min = √(α_s/σ). -/
113noncomputable def r_min : ℝ := Real.sqrt (alpha_strong / stringTension)
114
115/-- r_min is positive. -/
116theorem r_min_pos : 0 < r_min :=
117 Real.sqrt_pos_of_pos (div_pos alpha_strong_pos stringTension_pos)
118
119/-- α_s/σ is positive (both terms are positive). -/
120theorem alpha_over_sigma_pos :
121 0 < alpha_strong / stringTension := by
122 exact div_pos alpha_strong_pos stringTension_pos
123
124/-- α_s/σ > 1 (strong coupling exceeds string tension). -/
125theorem alpha_over_sigma_gt_one :
126 1 < alpha_strong / stringTension := by
127 have hα : alpha_strong = 2/17 := by unfold alpha_strong alpha_s_geom; norm_num
128 have hσ := stringTension_bounds
129 have hσ_pos := stringTension_pos
130 -- 1 < (2/17) / σ: cross-multiply by σ to get σ < 2/17
131 rw [hα]
132 have hσ_ne : stringTension ≠ 0 := ne_of_gt hσ_pos
133 have hgoal : stringTension < 2/17 := by nlinarith [hσ.2]
134 calc 1 = stringTension / stringTension := (div_self hσ_ne).symm
135 _ < (2/17) / stringTension := by
136 apply div_lt_div_of_pos_right hgoal hσ_pos
137
138/-- Strong coupling is larger than EM coupling. -/
139theorem strong_vs_em : (1/137 : ℝ) < alpha_strong := by
140 unfold alpha_strong alpha_s_geom; norm_num
141
142end
143