-- Verify formulas for electron scattering E = sqrt(p^2 + m^2) p1 = (E, 0, 0, p) p2 = (E, 0, 0, -p) p3 = (E, p expsin(theta) expcos(phi), p expsin(theta) expsin(phi), p expcos(theta)) p4 = (E, -p expsin(theta) expcos(phi), -p expsin(theta) expsin(phi), -p expcos(theta)) I = ((1,0,0,0),(0,1,0,0),(0,0,1,0),(0,0,0,1)) gmunu = ((1,0,0,0),(0,-1,0,0),(0,0,-1,0),(0,0,0,-1)) gamma0 = ((1,0,0,0),(0,1,0,0),(0,0,-1,0),(0,0,0,-1)) gamma1 = ((0,0,0,1),(0,0,1,0),(0,-1,0,0),(-1,0,0,0)) gamma2 = ((0,0,0,-i),(0,0,i,0),(0,i,0,0),(-i,0,0,0)) gamma3 = ((0,0,1,0),(0,0,0,-1),(-1,0,0,0),(0,1,0,0)) gamma = (gamma0,gamma1,gamma2,gamma3) gammaT = transpose(gamma) gammaL = transpose(dot(gmunu,gamma)) pslash1 = dot(p1,gmunu,gamma) pslash2 = dot(p2,gmunu,gamma) pslash3 = dot(p3,gmunu,gamma) pslash4 = dot(p4,gmunu,gamma) X1 = pslash1 + m I X2 = pslash2 + m I X3 = pslash3 + m I X4 = pslash4 + m I T1 = contract(dot(X3,gammaT,X1,gammaT),1,4) T2 = contract(dot(X4,gammaL,X2,gammaL),1,4) f11 = contract(dot(T1,transpose(T2))) T = contract(dot(X3,gammaT,X1,gammaT,X4,gammaL,X2,gammaL),1,6) f12 = contract(contract(T,1,3)) T1 = contract(dot(X4,gammaT,X1,gammaT),1,4) T2 = contract(dot(X3,gammaL,X2,gammaL),1,4) f22 = contract(dot(T1,transpose(T2))) "Verify momentum formulas (1=ok)" f11 == 32 dot(p1,gmunu,p2)^2 + 32 dot(p1,gmunu,p4)^2 - 64 m^2 dot(p1,gmunu,p3) + 64 m^4 f12 == -32 dot(p1,gmunu,p2)^2 + 32 m^2 dot(p1,gmunu,p2) + 32 m^2 dot(p1,gmunu,p3) + 32 m^2 dot(p1,gmunu,p4) - 32 m^4 f22 == 32 dot(p1,gmunu,p2)^2 + 32 dot(p1,gmunu,p3)^2 - 64 m^2 dot(p1,gmunu,p4) + 64 m^4 "Verify Mandelstam formulas (1=ok)" s = dot(p1 + p2,gmunu,p1 + p2) t = dot(p1 - p3,gmunu,p1 - p3) u = dot(p1 - p4,gmunu,p1 - p4) f11 == 8 s^2 + 8 u^2 - 64 s m^2 - 64 u m^2 + 192 m^4 f12 == -8 s^2 + 64 s m^2 - 96 m^4 f22 == 8 s^2 + 8 t^2 - 64 s m^2 - 64 t m^2 + 192 m^4 m = 0 s == 4 E^2 t == 2 E^2 (expcos(theta) - 1) u == -2 E^2 (expcos(theta) + 1) "Verify probability density (1=ok)" d11 = t^2 d12 = t u d22 = u^2 A = 1/4 (f11/d11 - 2 f12/d12 + f22/d22) B = 4 (expcos(theta)^2 + 3)^2 / (expcos(theta)^2 - 1)^2 A == B -- Zee formula A = 2 ((1 + expcos(theta/2)^4) / expsin(theta/2)^4 + 2 / (expsin(theta/2)^2 expcos(theta/2)^2) + (1 + expsin(theta/2)^4) / expcos(theta/2)^4) B = 4 (expcos(theta)^2 + 3)^2 / (expcos(theta)^2 - 1)^2 A == B
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