CP-Violation and Particle Oscillations

  • Sylvie Braibant
  • Giorgio Giacomelli
  • Maurizio Spurio
Part of the Undergraduate Lecture Notes in Physics book series (ULNP)


The CP transformation combines the charge conjugation C and parity P operators. If CP is an exact symmetry, the laws of nature would be completely identical for matter and antimatter. Most of the observed phenomena are symmetric with respect to C and P, and consequently symmetric to CP. Exceptions are the weak interaction, which violates C and P maximally. CP-violation is a necessary condition for baryogenesis, i.e., the dynamic process generating matter-antimatter asymmetry in the Universe. The Universe seems to be made of matter, with almost no antimatter. Despite the phenomenological success of the mechanism that describes the CP-violation in the Standard Model (which is presented in different problems using both the \(K^{0}-\overline{K}^{\,0}\) and \(B^{0}-\overline{B}^{\,0}\) oscillations), there are probably additional, still unknown, sources of CP-violation to explain the observed matter-antimatter asymmetry in the Universe. In its original formulation, the Standard Model assumes massless neutrinos. A first indication of physics beyond the SM are neutrino oscillations (possible only with massive neutrinos). Problems discussing solar and atmospheric neutrino oscillations are included. In the most conventional scheme, neutrinos are Dirac particles: ν’s can be distinguished from \(\overline{\nu}\)’s through their interactions. There is no reason to exclude the possibility that neutrinos are Majorana particles: i.e., members of a doublet in which neutrinos coincide with their own antiparticles. The ν is the left-handed component of the doublet while the \(\overline{\nu}\) is the right-handed one. The possibility to distinguish between the Dirac or Majorana hypothesis is presented in Supplement 12.2.


Neutrino Mass Neutrino Oscillation Atmospheric Neutrino Mass Eigenstates Majorana Neutrino 
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Copyright information

© Springer Science+Business Media Dordrecht 2012

Authors and Affiliations

  • Sylvie Braibant
    • 1
  • Giorgio Giacomelli
    • 1
  • Maurizio Spurio
    • 1
  1. 1.Department of Physics and INFNUniversity of BolognaBolognaItaly

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