hw21 - ϕ 3-theory described by the Lagrangian density L =...

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Homework Set No. 1, Physics 880.08 Deadline – Wednesday, January 19, 2011 1. Consider real scalar ϕ 4 -theory described by the Lagrangian density L = 1 2 μ ϕ∂ μ ϕ m 2 2 ϕ 2 λ 4! ϕ 4 . a. (10 pts) Draw all connected Feynman diagrams contributing to the two-point function a ψ 0 | ( x ) ϕ ( y ) | ψ 0 A at the order λ 3 . Find the symmetry factors for all the graphs. b. (15 pts) Draw all connected (= no vacuum bubbles) Feynman diagrams contributing to the four-point function a ψ 0 | ( x 1 ) ϕ ( x 2 ) ϕ ( x 3 ) ϕ ( x 4 ) | ψ 0 A up to the order λ 3 . Calculate the symmetry factors. c. (5 pts) What is the symmetry factor of the following Feynman diagram? 2. Consider real scalar
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Unformatted text preview: ϕ 3-theory described by the Lagrangian density L = 1 2 ∂ μ ϕ∂ μ ϕ − m 2 2 ϕ 2 − λ 3! ϕ 3 . a. (10 pts) Draw all connected Feynman diagrams contributing to the two-point function a ψ | Tϕ ( x ) ϕ ( y ) | ψ A up to the order λ 4 . Find the symmetry factors. b. (10 pts) Draw all connected (= no vacuum bubbles) Feynman diagrams contributing to the three-point function a ψ | Tϕ ( x 1 ) ϕ ( x 2 ) ϕ ( x 3 ) | ψ A up to the order λ 3 . Calculate the symmetry factors. 1...
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This note was uploaded on 07/28/2011 for the course PHYSICS 880.08 taught by Professor Staff during the Fall '10 term at Ohio State.

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