Feynman Diagrams For Pedestrians - Herbstschule Maria Laach
Feynman Diagrams For Pedestrians - Herbstschule Maria Laach
Feynman Diagrams For Pedestrians - Herbstschule Maria Laach
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– . . . two different reductions in the same FORM program require advancedtricks . . .• running the program:ohl@thopad2:~fdfp$ form bhabha.frmFORM by J.Vermaseren,version 3.3(Mar 28 2009) Run at: Thu Jul 7 18:37:42 2011[SS*] =+ me^2 * ( - 64*u - 64*t )+ me^4 * ( 192 )+ 8*u^2 + 8*t^2;[TT*] =+ me^2 * ( - 64*u )+ me^4 * ( 64 )+ 16*u^2 + 16*t*u + 8*t^2;[ST*] =+ me^2 * ( 64*u )+ me^4 * ( - 96 )- 8*u^2;[TS*] =+ me^2 * ( 64*u )+ me^4 * ( - 96 )- 8*u^2;0.00 sec out of 0.00 sec• NB: |T s | 2 (t, u) = |T t | 2 (s, u)• final result very symmetrical∑spinsProblem 19. Compute the differential cross section( )tTT ∗ = 8e 4 2 + u 2+ s2 + u 2+ 2u2 + O(m 2s 2 t 2 ste) (144)for Bhabha scattering in the region s, −t, −u ≫ m 2 e.dσ(cos θ) (145)dΩ30