3 ms·

Ok, how many free parameters are in the standard model? Ask five random physics professors, insist on an answer while declining to answer questions for clarifi

Ok, how many free parameters are in the standard model? Ask five random physics professors, insist on an answer while declining to answer questions for clarification. I guarantee you get at least two answers, maybe three (that's assuming you manage to get an answer from each...). See also people giving various possible answers on physics stack exchange...

JumpCrisscross 1y ago
You’re acting like the SM is an unfalsifiable string theory that just revises all of its parameter every time the last batch is disproven. It’s not. SM is not fully developed. And we know where it is wrong or painfully silent, e.g. neutrinos and gravity. But it’s a rigorous theory, possibly the most rigorous our species has ever developed, with central tenets that have held to ridiculous levels of precision. Of course there are conflicting hypotheses at its frontier. That’s sort of what defines the frontier. But at its core, the SM is robust. So robust that we mostly don’t talk about it, obsessing—as science should—with the parts where it doesn’t fit together as perfectly.
- staunton 1y ago
  I'm saying that the standard model is evolving and there's no authority or institution that gets to definine what "the standard model" means. All of this is completely reasonable. Maybe it can evolve forever to accommodate new results (e.g. by adding new fields), likely it can't (it's hard to imagine a reasonable modification for breaking CPT symmetry, not that this is the best example). If at any point noone can figure out how to evolve it before a radically different theory emerges to explain current discrepancies, we'll have what Kuhn might call a "paradigm shift", say "the standard model is falsified", and invent a different name for the new theory. I even included this possibility in my original comment, so I'm not sure what gave you offense... That's completely unrelated to any given instance of this evolution being falsifiable. Each of them is, they stick around for a while and there aren't that many. All very proper, Popper is happy. Meanwhile, string theory hasn't produced a single prediction that was later observed experimentally and one can even argue whether it has produced any predictions at all...
  - JumpCrisscross 1y ago
    > the standard model is evolving and there's no authority or institution that gets to definine what "the standard model" means The standard model per se is not materially evolving. We're bolting extensions onto it. And there is disagreement over what those extensions mean, whether they're true, and what free parameters they may add. > Maybe it can evolve forever to accommodate new results (e.g. by adding new fields) The Higgs field was the last field to have been "added" to the model. Its existence wasn't prompted by experimentation, but vice versa.
avpix 1y ago
19, each corresponding to a physical quantity that can be measured. https://en.wikipedia.org/wiki/Mathematical_formulation_of_the_Standard_Model#Free_parameters https://en.wikipedia.org/wiki/Mathematical_formulation_of_th...
- staunton 1y ago
  See https://physics.stackexchange.com/questions/172846/free-parameters-in-the-standard-model#172847 https://physics.stackexchange.com/questions/172846/free-para... for the other options.
  - JumpCrisscross 1y ago
    Could you help me with which variable we should focus on?
    - staunton 1y ago
      > Could you help me with which variable we should focus on? I'm not sure what you mean... I'm not asking anyone to focus on anything?! The answers I linked suggest several different numbers, e.g. 19, 25, 26, I've heard people suggest adding even more "non-Higgs caused masses" since "neutrinos have those and you should add all parameters you can't find theoretical reasons to rule out"...)
      - JumpCrisscross 1y ago
        > answers I linked suggest several different numbers, e.g. 19, 25, 26 But there is no actual ambiguity. 19 in the original formulation. 26 with the PMNS bolt-on. Other numbers with other bolt-ons. The argument is over the extensions.
        staunton 1y ago
        It was about the phrase "the standard model", which doesn't specify what "extensions" are implied. You seem to think it means "no extensions" to a somewhat arbitrarily chosen step of the evolution, which has 19 free parameters. I don't think that's how most people use the phrase. As far as I can tell, we are in complete agreement on all other points... I still think my original comment, which seems to have given you offense for some reason, was completely appropriate. "The standard model" means "state of the art particle physics without highly speculative stuff", at least until we have a paradigm shift.
AnimalMuppet 1y ago
If you decline to answer questions for clarification, it seems fair that they should decline to answer your question.

JumpCrisscross 1y ago

You’re acting like the SM is an unfalsifiable string theory that just revises all of its parameter every time the last batch is disproven. It’s not. SM is not fully developed. And we know where it is wrong or painfully silent, e.g. neutrinos and gravity. But it’s a rigorous theory, possibly the most rigorous our species has ever developed, with central tenets that have held to ridiculous levels of precision. Of course there are conflicting hypotheses at its frontier. That’s sort of what defines the frontier. But at its core, the SM is robust. So robust that we mostly don’t talk about it, obsessing—as science should—with the parts where it doesn’t fit together as perfectly.

staunton 1y ago
I'm saying that the standard model is evolving and there's no authority or institution that gets to definine what "the standard model" means. All of this is completely reasonable. Maybe it can evolve forever to accommodate new results (e.g. by adding new fields), likely it can't (it's hard to imagine a reasonable modification for breaking CPT symmetry, not that this is the best example). If at any point noone can figure out how to evolve it before a radically different theory emerges to explain current discrepancies, we'll have what Kuhn might call a "paradigm shift", say "the standard model is falsified", and invent a different name for the new theory. I even included this possibility in my original comment, so I'm not sure what gave you offense... That's completely unrelated to any given instance of this evolution being falsifiable. Each of them is, they stick around for a while and there aren't that many. All very proper, Popper is happy. Meanwhile, string theory hasn't produced a single prediction that was later observed experimentally and one can even argue whether it has produced any predictions at all...
- JumpCrisscross 1y ago
  > the standard model is evolving and there's no authority or institution that gets to definine what "the standard model" means The standard model per se is not materially evolving. We're bolting extensions onto it. And there is disagreement over what those extensions mean, whether they're true, and what free parameters they may add. > Maybe it can evolve forever to accommodate new results (e.g. by adding new fields) The Higgs field was the last field to have been "added" to the model. Its existence wasn't prompted by experimentation, but vice versa.

avpix 1y ago

19, each corresponding to a physical quantity that can be measured. https://en.wikipedia.org/wiki/Mathematical_formulation_of_the_Standard_Model#Free_parameters https://en.wikipedia.org/wiki/Mathematical_formulation_of_th...

staunton 1y ago
See https://physics.stackexchange.com/questions/172846/free-parameters-in-the-standard-model#172847 https://physics.stackexchange.com/questions/172846/free-para... for the other options.
- JumpCrisscross 1y ago
  Could you help me with which variable we should focus on?
  - staunton 1y ago
    > Could you help me with which variable we should focus on? I'm not sure what you mean... I'm not asking anyone to focus on anything?! The answers I linked suggest several different numbers, e.g. 19, 25, 26, I've heard people suggest adding even more "non-Higgs caused masses" since "neutrinos have those and you should add all parameters you can't find theoretical reasons to rule out"...)
    - JumpCrisscross 1y ago
      > answers I linked suggest several different numbers, e.g. 19, 25, 26 But there is no actual ambiguity. 19 in the original formulation. 26 with the PMNS bolt-on. Other numbers with other bolt-ons. The argument is over the extensions.
      - staunton 1y ago
        It was about the phrase "the standard model", which doesn't specify what "extensions" are implied. You seem to think it means "no extensions" to a somewhat arbitrarily chosen step of the evolution, which has 19 free parameters. I don't think that's how most people use the phrase. As far as I can tell, we are in complete agreement on all other points... I still think my original comment, which seems to have given you offense for some reason, was completely appropriate. "The standard model" means "state of the art particle physics without highly speculative stuff", at least until we have a paradigm shift.

AnimalMuppet 1y ago

If you decline to answer questions for clarification, it seems fair that they should decline to answer your question.