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The Feynman diagrams are much easier to keep track of than "old-fashioned" terms, because the old-fashioned way treats the particle and antiparticle contributions as separate. Each Feynman diagram is the sum of exponentially many old-fashioned terms, because each internal line can separately represent either a particle or an antiparticle.
Generation of QED Feynman graphs at any order in the coupling constant was automatized in the late 70's[15]. One of the first major application of these early developments in this field was the calculation of the anomalous magnetic moments of the electron and the muon[16].
FORM has been the essential tool to calculate the higher-order QCD beta function. The mathematical structure of multiple zeta values has been researched with dedicated FORM programs. [2] The software package FormCalc which is widely used in the physics community to calculate Feynman diagrams is built on top of FORM.
To calculate the probability of any interactive process between electrons and photons, it is a matter of first noting, with Feynman diagrams, all the possible ways in which the process can be constructed from the three basic elements. Each diagram involves some calculation involving definite rules to find the associated probability amplitude.
The Casimir effect, Hawking radiation and Lamb shift are examples of phenomena whose existence can be implied using one-loop Feynman diagrams, especially the well-known "triangle diagram": The evaluation of one-loop Feynman diagrams usually leads to divergent expressions, which are either due to: zero-mass particles in the cycle of the diagram ...
Interactions in the Standard Model. All Feynman diagrams in the model are built from combinations of these vertices. q is any quark, g is a gluon, X is any charged particle, γ is a photon, f is any fermion, m is any particle with mass (with the possible exception of the neutrinos), m B is any boson with mass. In diagrams with multiple particle ...
In the Stückelberg–Feynman interpretation, pair annihilation is the same process as pair production: Møller scattering: electron-electron scattering Bhabha scattering: electron-positron scattering Penguin diagram: a quark changes flavor via a W or Z loop Tadpole diagram: One loop diagram with one external leg Self-interaction or oyster diagram
In Feynman diagrams, which serve to calculate the rate of collisions in quantum field theory, virtual particles contribute their propagator to the rate of the scattering event described by the respective diagram.