Standard model, mass prediction

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Discussion Overview

The discussion revolves around the Standard Model of particle physics, specifically addressing the question of why the model does not inherently predict particle masses and how it manages to provide mass predictions through other means. The scope includes theoretical aspects and conceptual clarifications related to particle mass and the Higgs mechanism.

Discussion Character

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

Main Points Raised

  • One participant notes that the Standard Model does not predict that matter inherently has mass, questioning how it can still predict particle masses.
  • Another participant suggests that particle masses are treated as free parameters within the Standard Model, indicating that these values must be experimentally determined rather than predicted by the theory.
  • A further contribution explains that all particles in the Standard Model are massless until the Higgs mechanism is applied, which generates masses for weak gauge bosons based on the Higgs field's vacuum expectation value.
  • It is mentioned that Yukawa couplings provide masses for other elementary particles, but these values are also considered model parameters and are not predicted by the Standard Model.
  • One participant emphasizes the need for precise references when discussing claims made on the CERN website, highlighting the ambiguity in the original question.

Areas of Agreement / Disagreement

Participants express differing views on the nature of mass predictions in the Standard Model, with some clarifying the role of the Higgs mechanism and Yukawa couplings while others question the adequacy of the original reference. No consensus is reached regarding the implications of these points.

Contextual Notes

The discussion highlights limitations in understanding the Standard Model's treatment of mass, particularly regarding the dependence on experimental parameters and the ambiguity in the original source referenced.

jamie.j1989
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Hi, I've read on the cern website that the standard model does not predict that matter inherently has mass, if this is the case how does the model predict particle masses and also why doesn't it predict that matter inherently has mass? Thanks.
 
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I guess the reason why is because the Standard Model has the particle masses as free parameters... It won't change much by choosing any value for them...
That is why it's unable to predict the particle masses and you have to experimentally determine them and plug them in the theory.
 
It is usual to provide a reference more precise than "somewhereon the CERN homepage" when you are asking for a clarification. As it is now we have to guess exactly what was said.

Inherently, all particles in the SM are massless until the theory is spontaneously broken by the Higgs mechanism, which by itself produces masses to the weak gauge bosons based on the vacuum expectation value taken by the Higgs field. Other elementary particle masses can be provided by Yukawa couplings, which have values that are model parameters and thus are not predicted.

Without more information, it is impossible to tell exactly which part of the above that the homepage was referring to.
 

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