Higgs, Fermi-Dirac distribution, and Pauli exclusion principle

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Discussion Overview

The discussion revolves around the Higgs Mechanism, specifically focusing on the implications of spontaneous symmetry breaking (SSB) in the early universe, the behavior of particle masses, and the application of the Fermi-Dirac distribution and the Pauli exclusion principle in a hot, massless state. The scope includes theoretical aspects and conceptual clarifications related to particle physics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that the masses of particles scale with the vacuum expectation value (VEV) of the Higgs, suggesting that fluctuations will be significant near the transition point where SSB occurs.
  • Another participant questions the implications of the VEV growing continuously from zero, seeking clarification on the behavior of the system between specific time points (t1 and t3) during the transition.
  • There is a mention of the importance of triple and quartic Higgs vertices in the context of fluctuations dominating near the transition point, although the reasoning behind this is not fully explained.
  • Some participants express confusion regarding the definitions of the time points t1 and t3, indicating a lack of clarity in the discussion.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the significance of the time points t1 and t3, and there is uncertainty regarding the implications of the Higgs mechanism during the transition period. The discussion remains unresolved on these points.

Contextual Notes

Limitations include unclear definitions of time points t1 and t3, and the dependence on specific models (e.g., Ginzburg-Landau) for understanding the behavior of the VEV and particle masses during the transition.

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hi,

I am studying the Higgs Mechanism these days. And I get two questions. I hope some ones could help me.

1>We know that due to the non-zero VEV, SSB takes place and higgs condensates give masses to bosons and fermions. I wonder that after the SSB and before the universe became as cool as today, what are different points? All the masses should be smaller, and what about renormalization?

2>When the universe was hot enough that all partiles are massless, what Fermi-Dirac distribution and Pauli exclusion principle would be ?

Thanks.
 
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1. The masses scale with the VEV of the Higgs. Using a Ginzburg-Landau model, the VEV grows continuously from zero, but with a divergent rate at the point of transition. However, that's assuming that the temperature corresponds to the quadratic term in the GL model. Furthermore, fluctuations (both thermal and quantum) will be important. Near the transition point fluctuations will dominate, and the quadratic treatment will be insufficient; diagrams containing the the three and four Higgs vertices will become increasing important.

2. Nothing changes.
 
Thank you.

In the picture, the Fig. 1 is used by many people to explain Higgs mechanism. When t<t1, SSB does not happen, and when t>t3, we have W/Z. Since I am not sure the exact meaning of "the VEV grows continuously from zero", I want to know when t1<t<t3, which one is correct, Fig.2, Fig.3 or neither?

And I cannot figure out why triple and quartic Higgs vertices are important in this case. Could you explain me more about this?
 

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Last edited:
I don't see what t1 and t3 are.
 
genneth said:
I don't see what t1 and t3 are.

t1 is the time that before t1, SSB does not take place. And t3>t1, after t3 the maxima VEV appears.
 

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