The discussion centers on the theoretical necessity of the 4th generation of particles in the context of anomaly cancellation and multiplet completeness. While the 3rd generation is essential for anomaly cancellation, the 4th generation remains a topic of interest due to its theoretical allowance and potential contributions to physics, particularly in scenarios involving non-standard Higgs bosons. Experimental evidence suggests that 4th generation particles are likely too heavy and unstable for direct detection in colliders, yet they may still influence lower-energy processes through loop contributions. The ongoing research into the 4th generation highlights its relevance in advanced theoretical frameworks.
PREREQUISITESParticle physicists, theoretical physicists, and researchers interested in the implications of higher generations in the Standard Model and beyond.
That's not quite true.Accidently said:3 generation is required for anomaly cancellation ...
It's allowed theoretically, just as the 2nd and 3rd one.Accidently said:But there are still papers about the 4th generation, what is the reason?
tom.stoer said:I am not absolutely sure but I thought that a 4th generation is almost certainly ruled out experimentally (the 4th generation particles would be too heavy to be produced directly in colliders, they may by too instable to be detected directly, but they do contribute to loops even at lower energies therefore there are indirect indications regarding the number of generations).