Feynman diagrams

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    • feynman diagrams allow us to draw interactions
    • feynman diagrams are drawn on a slant to show time passing
    • The squiggle in the middle of a fireman diagram shows the exchange particles
    • the gauge boson associated with nucleons is the pion
    • gauge bone associated with corks is the gluon
    • beta minus decay?

      Neutron turns into a proton electron and antielectron neutrino
    • beta minus decay?

      n -> p + e- + ve-
    • in beta minus decay the neutron decay to a proton and a w- boson is emitted
    • The W- boson emitted in beta minus decay transfers a negative charge across to the other side so the charge balances.
    • beta plus decay?

      protein decays into a neutron , positron and an electron neutrino
    • beta plus decay?

      p -> n + e+ + ve
    • in beta plus decay, a proton decays to a neutron and a w+ boson is emitted
    • the w+ boson in beta plus decay carries the charge to the positron
    • beta minus decay
    • beta plus decay
    • electron captureweak interaction
    • electron proton collision is not an electromagnetic interaction
    • electron capture?

      p+ e- -> n + ve
    • electron-proton collision?

      p + e- -> n + ve
    • in electron capture, proton rich nuclei capture an orbital electron from inside the atom and change it into a neutron
    • in electron capture a proton decays to a neutron and a W plus boson is emitted. this interacts with electron to produce the electron neutrino
    • in electron capture the W plus boson arrow is towards the right because the proton decays into it ( coming from it )
    • in an electron-proton collision, the electron collides with the proton and the w- boson comes from the electron so the arrow is pointing left/down.
    • electron capture
    • electron- proton collision
    • antiparticles move back in time
    • electromagnetic repulsion - the exchange particle is a gamma photon
    • electromagnetic repulsion
    • neutrino interactions are not very common
    • neutrino interactions?

      • p + ve- -> n + e+ = this has a w+ boson
      • n + ve -> p + e- = this has a w- boson
      • p + ve- -> n + e+
      • n + ve -> p + e-
    • all decays involve W plus or W minus bosons
    • exchange particles:
      • electromagnetic repulsion - gamma photon
      • beta minus decay - w- boson right
      • beta plus decay - w+ boson right
      • electron capture - w+ boson right
      • electron-photon collision - w- boson left
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