Symmetry Factors of Feynman Diagrams for Scalar Fields
نویسندگان
چکیده
The symmetry factor of Feynman diagrams for real and complex scalar fields is presented. Being analysis of Wick expansion for Green functions, the mentioned factor is derived in a general form. The symmetry factor can be separated into two ones corresponding to that of connected and vacuum diagrams. The determination of symmetry factors for the vacuum diagrams is necessary as they play a role in the effective action and phase transitions in cosmology. In the complex scalar theory the diagrams different in topology may give the same contribution, hence inverse of the symmetry factor (1/S) for total contribution is a summation of each similar ones (1/Si), i.e., 1/S = ∑ i(1/Si). PACS number(s): 11.15.Bt, 12.39.St.
منابع مشابه
A General Expression for Symmetry Factors of Feynman Diagrams
The calculation of the symmetry factor corresponding to a given Feynman diagram is well known to be a tedious problem. We have derived a simple formula for these symmetry factors. Our formula works for any diagram in scalar theory (φ3 and φ4 interactions), spinor QED, scalar QED, or QCD. PACS numbers:11.10.-z, 11.15.-q, 11.15.Bt Typeset using REVTEX 1
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