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SMdata

Outline

  • non-field theory (Halzen)
  • Introduction to SM
  • External/Internal Particles
  • Interactions and Feynman Rules
  • QED
  • QFT (Peskin)
  • \(e^+e^-\to\mu^+\mu^-\)
    • Feynman Diagrams
    • Dirac Algebra
  • Crossing Symmetry
  • Helicity Structure
  • \(e^+e^-\to\gamma\gamma\)
  • \(\tau\to W b\)

Introduction

  • QFT
  • Spontaneous symmetry breaking
  • Perturbative region
  • Non-perturbative region
  • Renormalisability SM: \(SU(3)\otimes SU(2) \otimes U(1)\) color and broken electroweak
  • Particle content of SM
  • 3 generation for the spin-\(\frac{1}{2}\) fermions
  • spin-\(1\): \(g,\gamma,Z,W^\pm\)
  • spin-\(0\): Higgs
  • Expending Lagrangian
  • Dark matter
  • Neutrinos Oscillate
  • Matter and anti-matter asymmetry

Scattering

\[\text{Cross-Section}\approx \text{Scattering likelihood} \times \text{Scattering configuration} / \text{Incoming flux}\]
\[d\sigma_{AB\to fX}^{\text{Theory}}=\frac{\sum_{ndf}|A_{AB\to fX}|^2d\phi_{fX}}{2S}\]

Here \(\phi\) means the phase space.

  • Amplitude
  • \(A(I\to F)\sim \sum_{l} g^2\sum(l~\text{loops for feynman diagrams})\) \(g\) is the \(g\) coupling constant
  • \(l=0\) tree level
    1. Identify Feynman diagram
    2. Apply Feynman rules
    3. \(A=\sum_{i}F_i\) - \(F_i\) Feynman diagram
    4. \(|A|^2\)

QED

Klein-Gordon Equation

\[-\frac{\partial ^2 \phi}{\partial t^2}+\nabla^2\phi = m^2\phi\]

Here \(\phi(x,t)=Ne^{-i\rho^\mu x_\mu}\) and \(E^2=\vec{p}^2+m^2\), the \(\vec{p}\) is a three vector

Dirac Equation

\[\partial^{\mu=0,1,2,3}=\left(\frac{\partial}{\partial t},-\vec{\nabla}\right)\]

最后更新: 2023年9月8日