impact parameter meaning in French

paramètre d'impact

The impact parameter b {\displaystyle b} is defined as the perpendicular distance between the path of a projectile and the center of a potential field U ( r ) {\displaystyle U(r)} created by an object that the projectile is approaching (see diagram).
Le paramètre d'impact b
For small angles α1 the total deflection by a point mass M is given (see Schwarzschild metric) by α 1 = 4 G c 2 M b 1 {\displaystyle \alpha _{1}={\frac {4G}{c^{2}}}{\frac {M}{b_{1}}}} where b1 is the impact parameter (the distance of nearest approach of the lightbeam to the center of mass) G is the gravitational constant, c is the speed of light.
Pour une masse ponctuelle (M), selon la métrique de Schwarzschild et pour un petit αb1, la déviation totale est donnée par : α 1 = 4 G c 2 M b 1
The impact parameter is related to the scattering angle θ {\displaystyle \theta } by θ = π − 2 b ∫ r m i n ∞ d r r 2 1 − ( b / r ) 2 − 2 U / m v ∞ 2 {\displaystyle \theta =\pi -2b\int _{r_{\mathrm {min} }}^{\infty }{\frac {dr}{r^{2}{\sqrt {1-(b/r)^{2}-2U/mv_{\infty }^{2}}}}}} where v ∞ {\displaystyle v_{\infty }} is the velocity of the projectile when it is far from the center, and r m i n {\displaystyle r_{\mathrm {min} }} is its closest distance from the center.
Le paramètre d'impact est relié à l'angle de diffusion (scattering angle en anglais) θ