What parameters of SM can be changed gradually?

[Dmitry67]

For example, mass spectrum can't vary because energy is conserved (locally).
What's about other parameters? Could CKM angles be different in earlier époque? It could save the Sakharov’s mechanism, if CP violation was more intense during bareogenesis.

 

[Demystifier]

The answer depends on what do you mean by "can".
Anything is possible, unless you specify some constraint (which you don't).
In principle, any constant in SM (including the masses) could be a variable, but then it would not be described by SM any more.

 

[Dmitry67]

SM itself does not explain WHY parameters have the values we observe.
So it does not put any constrains on them.

Mass can't be variable - it would be absolutely different physics, because enrgy won't be conserved.

 

[Demystifier]

SM itself does not explain WHY parameters have the values we observe.

That's true.

So it does not put any constrains on them.

It puts at least one constraint: They must be - constant!

Mass can't be variable - it would be absolutely different physics, because enrgy won't be conserved.

That's not true, it is easy to write a Lagrangian with a dynamical effective mass with a conserved Hamiltonian. In fact, the Lagrangian describing the Higgs mechanism, which is a part of the SM, is one such Lagrangian.

 

[vanhees71]

That's not true, it is easy to write a Lagrangian with a dynamical effective mass with a conserved Hamiltonian. In fact, the Lagrangian describing the Higgs mechanism, which is a part of the SM, is one such Lagrangian.

In fact, in any relativistic QFT "mass" becomes a dynamical quantity through the non-vanishing self-energies of the particles.

In many-body theory this even happens for non-relativistic particles: In the most simple case one can describe the many-body system as a dilute quantum gas of quasi-particles, which may have the same quantum numbers as the elementary constituents (e.g., electrons in a condensed-matter system) but with different effective masses or charges. Other quasi-particle excitations (effective degrees of freedom) may not be medium modifications of elementary constituents but collective modes like phonons (lattice vibrations) in a solid body, plasmons/plasminos (plasma oscillations) in a plasma,...

 

[Dmitry67]

Interesting - I did not think about that.
Thanks