7 ms·

What the Higgs boson tells us about the universe

86 points by sohkamyung 4y ago

dilivion 4y ago
The discovery of the Higss boson and nothing else outside the Standard Model at the LHC is the worst-case scenario: we now have a theory of everything that predicts nothing...
- Donckele 4y ago
  Ooof! Spoiler alert!
- evanb 4y ago
  "That predicts nothing" is very far from the truth! It predicts almost everything we have ever observed experimentally!
  - ninkendo 4y ago
    It predicts things we’ve already observed, sure. But we came up with the standard model after seeing what ideas worked and which ones didn’t, and we get to amend it every time an experiment shows us something new. The standard model isn’t some single theory that was devised and survived testing. It’s an amalgam of various ideas which have survived experimental verification. It’s a bit hollow IMO to say it “predicts” things. It’s a bit like drawing the dartboard after throwing the darts.
    - quchen 4y ago
      … and later throwing more and more darts and still hitting the center.
    - evanb 4y ago
      It predicts much more than what has been put in. The SM has 22 free parameters. I agree that if it predicted exactly 22 data points it'd be a pointless encoding of what was put in. But it predicts thousands and thousands of data points, some to twelve decimal points. It predicts things as-yet-unseen, also, such as detailed proton structure, precision atomic matrix elements, detailed nuclear structure and decay rates, and so on.
      - bannedbybros 4y ago
        [dead]
    - squeaky-clean 4y ago
      Well it predicted several things like the Higgs Boson, the top quark, Electroweak Unification, neutrinos...
      - btilly 4y ago
        Neutrinos were predicted and discovered long before the standard model. Note that the standard model did NOT predict neutrino mass. Though it did predict that neutrino mass would explain the shortfall of observed neutrinos from the Sun.
- morbia 4y ago
  The standard model is far from a 'theory of everything'. To name but a few problems: * gravity * massive neutrinos * dark matter * dark energy It is also a highly parameterised model tuned to fit the data. The biggest concern is whether we can realistically probe the failings of the standard model using a collider at ~TeV scale? If that is the case, then the standard model may be the best model of particle physics we will ever achieve.
  - evanb 4y ago
    "Highly parameterized" meaning O(20) free parameters. It matches thousands upon thousands of detailed precision data points.
    - marcosdumay 4y ago
      Pedantically, that's not how O notation works. But yeah, I agree that the "highly parameterized" part is a statement from fashion, and the number of parameters is really not a good reason to try to replace the Standard Model. (There are many good reasons, but this one isn't one of them.) Also, I am yet to see any alternative proposal with fewer parameters.
    - morbia 4y ago
      There is a philosophical discussion to be had about whether 19 physical parameters is "a lot", and another discussion about fine tuning. However, I was primarily referring to the artifical parameters that arise from doing real calculations (renormalisation scale, mass factorisation scale, PDFs etc). These plague pretty much all perturbative QCD calculations, and then particle physicists play games like varying them by a factor of 1/2 and 2 to get something that looks like error bars...
      - evanb 4y ago
        The number of SM parameters is not a lot, given the reach of the model, which is literally every physical phenomenon ever observed on Earth with enough detail, but gravity. Thousands of independent experiments, and observational data on a scale so absurdly large it's hard to state plainly. Any philosopher who wants to claim nineteen parameters is large is out of their minds! Fine tuning, I agree, is a philosophical issue. I'm a physicist, and I don't buy it. Why does everything have to be perturbatively pleasant? Nobody promised us that. The issue of artificial parameters is a red herring, I think. Properly computed, of course, well-defined observables are renormalization scale independent. You might have to pick a scheme/scale to do the calculation, but whatever scale dependence remains is an indication of some perturbative truncation. The continuum limit of LQCD, for example, produces real observables with no renormalization scale dependence. Hell, renormalization is not even mysterious in a computational approach.
- hyperman1 4y ago
  The standard model is basically a list of correctly working theories, taped together like the monster of Frankenstein. Nobody likes it. It's ugly as hell. Physicists, dreaming of some perfect symmetry driving the universe forwards all recoil in horror. Everybody thinks ot must be possible to make something better. Problem is, the monster works. After tuning a short list of parameters, it survives everything we can throw at it. We have trouble calculating the consequences, but that's not a failing of the model
  - Workaccount2 4y ago
    This a a pretty reaching take. The standard model has lots of short comings and definitely doesn't survive everything we throw at it, namely gravity and likewise general relativity.
    - thriftwy 4y ago
      If vacuum is meta-stable it is possible for entirely different set of fields to exist instead, but the gravity would be the same, I guess. This makes it outside of standard model.
- lucozade 4y ago
  I think you have it exactly backwards. The standard model is astonishingly good at predictions. It's just not a theory of everything. And the output from LHC has discounted some approaches to a TofE but hasn't helped to point the way to a strong candidate.
ianai 4y ago
I'd suggest anyone with a passing knowledge of calculus, complex numbers, and vectors to sit through Leonard Suskind's lectures on quantum gravity. This one was good and wouldn't need the calc/math background, I think: https://www.youtube.com/watch?v=-OkwGDKoY0o https://www.youtube.com/watch?v=-OkwGDKoY0o . But YT is full of actual physics lectures and sitting in on them is pretty approachable with that calc/math background. I think they give an interesting comparison to these popular pieces on particle physics. You might not understand everything the way a physics college student should, and that's ok because you aren't one. But I bet you walk away knowing quite a bit more than you suspect and you can always replay them. Pop-sci pieces tend to portray the universe as just a bunch of particles interacting in odd/spooky ways. It's a little reductive and sort of enshrines entanglement and similar concepts as unknowable at times. I skimmed this and it seems to spend a lot of time on spin 0 particles. Who knows, maybe that's a constraint from ER=EPR? But I didn't feel like it really conveys much about Higgs. (Which would serve a purpose - "oh you can't know it so please come back for next installment in my series of 10 books describing it." I don't think any authors actually set out with that as a goal, explicitly, but they could do a better pointing out where to go for further, more complicated edification. That sort of thing could shoehorn new talent into science.)
- dools 4y ago
  I watched every single one of the 163 lectures in that series. They're all amazing, and surprisingly addictive. As one YouTube commenter put it so aptly, I always looked forward to "snack time with Lenny".
  - abecedarius 4y ago
    Where is this series? The youtube link above seems to be to a standalone lecture. Trying the search terms from this discussion found two other standalone lectures. Is there some UI element on youtube that I'm missing that should make this obvious?
    - danbruc 4y ago
      The Theoretical Minimum [1] [1] https://theoreticalminimum.com/courses https://theoreticalminimum.com/courses
Scubabear68 4y ago
Interesting article, I think I actually understand a lot more than I usually do with physics articles. This quote stood out though. I lol’d: “The Higgs field, on the other hand, is just as spinless as the Higgs boson. Like a college senior sitting forlorn in a career counselor’s office, it has no direction”.
nyc111 4y ago
Were there any other observations of this particle after its discovery, do you know? Is it rare, or is it commonplace?
- denton-scratch 4y ago
  > Is it rare, or is it commonplace? From my understanding (/me not a physicist), it is rare. It's created only in high-energy situations, and decays extremely quickly. In the very beginning, there were a lot of them, but not for long. I gleaned from the article that the field is everywhere; I think it's correct to say that all fields are everywhere, but according to the article the Higgs field is distinctive: "The Higgs field has a nonzero vacuum expectation value throughout all of spacetime, meaning there is always some value associated with it, even when no Higgs particles are present." I guess, FSVO "present". If there were no Higgs particles anywhere, would the Higgs field disappear? I have no idea.
  - denton-scratch 4y ago
    (replying to self - sorry) > If there were no Higgs particles anywhere ...which is counterfactual, if you mean "anywhere in spacetime", because there were a lot of Higgs particles, at the very beginning; and those particles exist in spacetime. If there are no Higgs particles in spacetime, that's a different Universe. I guess (/me not a physicist).
  - prox 4y ago
    I always have trouble imagining the fields. Are they like Photoshop layers that work in the background?
    - danbruc 4y ago
      Those fields are a mathematical tool to describe what is going on in a specific way - for example making the local character of particle interactions obvious - but there is no evidence that there are actually any fields. Quite the opposite, a good reason to doubt that those fields are real is that they have Gauge redundancies, i.e. one physical state has several different mathematical representations.
1-6 4y ago
It's a good topic to ponder the existence of intelligent design.
- shsbdncudx 4y ago
  nah
kytazo 4y ago
As well as punching holes in the time space continuum
anthonyfantango 4y ago
[flagged]

86 points by sohkamyung 4y ago

The discovery of the Higss boson and nothing else outside the Standard Model at the LHC is the worst-case scenario: we now have a theory of everything that predicts nothing...

Donckele 4y ago
Ooof! Spoiler alert!
evanb 4y ago
"That predicts nothing" is very far from the truth! It predicts almost everything we have ever observed experimentally!
- ninkendo 4y ago
  It predicts things we’ve already observed, sure. But we came up with the standard model after seeing what ideas worked and which ones didn’t, and we get to amend it every time an experiment shows us something new. The standard model isn’t some single theory that was devised and survived testing. It’s an amalgam of various ideas which have survived experimental verification. It’s a bit hollow IMO to say it “predicts” things. It’s a bit like drawing the dartboard after throwing the darts.
  - quchen 4y ago
    … and later throwing more and more darts and still hitting the center.
  - evanb 4y ago
    It predicts much more than what has been put in. The SM has 22 free parameters. I agree that if it predicted exactly 22 data points it'd be a pointless encoding of what was put in. But it predicts thousands and thousands of data points, some to twelve decimal points. It predicts things as-yet-unseen, also, such as detailed proton structure, precision atomic matrix elements, detailed nuclear structure and decay rates, and so on.
    - bannedbybros 4y ago
      [dead]
  - squeaky-clean 4y ago
    Well it predicted several things like the Higgs Boson, the top quark, Electroweak Unification, neutrinos...
    - btilly 4y ago
      Neutrinos were predicted and discovered long before the standard model. Note that the standard model did NOT predict neutrino mass. Though it did predict that neutrino mass would explain the shortfall of observed neutrinos from the Sun.
morbia 4y ago
The standard model is far from a 'theory of everything'. To name but a few problems: * gravity * massive neutrinos * dark matter * dark energy It is also a highly parameterised model tuned to fit the data. The biggest concern is whether we can realistically probe the failings of the standard model using a collider at ~TeV scale? If that is the case, then the standard model may be the best model of particle physics we will ever achieve.
- evanb 4y ago
  "Highly parameterized" meaning O(20) free parameters. It matches thousands upon thousands of detailed precision data points.
  - marcosdumay 4y ago
    Pedantically, that's not how O notation works. But yeah, I agree that the "highly parameterized" part is a statement from fashion, and the number of parameters is really not a good reason to try to replace the Standard Model. (There are many good reasons, but this one isn't one of them.) Also, I am yet to see any alternative proposal with fewer parameters.
  - morbia 4y ago
    There is a philosophical discussion to be had about whether 19 physical parameters is "a lot", and another discussion about fine tuning. However, I was primarily referring to the artifical parameters that arise from doing real calculations (renormalisation scale, mass factorisation scale, PDFs etc). These plague pretty much all perturbative QCD calculations, and then particle physicists play games like varying them by a factor of 1/2 and 2 to get something that looks like error bars...
    - evanb 4y ago
      The number of SM parameters is not a lot, given the reach of the model, which is literally every physical phenomenon ever observed on Earth with enough detail, but gravity. Thousands of independent experiments, and observational data on a scale so absurdly large it's hard to state plainly. Any philosopher who wants to claim nineteen parameters is large is out of their minds! Fine tuning, I agree, is a philosophical issue. I'm a physicist, and I don't buy it. Why does everything have to be perturbatively pleasant? Nobody promised us that. The issue of artificial parameters is a red herring, I think. Properly computed, of course, well-defined observables are renormalization scale independent. You might have to pick a scheme/scale to do the calculation, but whatever scale dependence remains is an indication of some perturbative truncation. The continuum limit of LQCD, for example, produces real observables with no renormalization scale dependence. Hell, renormalization is not even mysterious in a computational approach.
hyperman1 4y ago
The standard model is basically a list of correctly working theories, taped together like the monster of Frankenstein. Nobody likes it. It's ugly as hell. Physicists, dreaming of some perfect symmetry driving the universe forwards all recoil in horror. Everybody thinks ot must be possible to make something better. Problem is, the monster works. After tuning a short list of parameters, it survives everything we can throw at it. We have trouble calculating the consequences, but that's not a failing of the model
- Workaccount2 4y ago
  This a a pretty reaching take. The standard model has lots of short comings and definitely doesn't survive everything we throw at it, namely gravity and likewise general relativity.
  - thriftwy 4y ago
    If vacuum is meta-stable it is possible for entirely different set of fields to exist instead, but the gravity would be the same, I guess. This makes it outside of standard model.
lucozade 4y ago
I think you have it exactly backwards. The standard model is astonishingly good at predictions. It's just not a theory of everything. And the output from LHC has discounted some approaches to a TofE but hasn't helped to point the way to a strong candidate.

ianai 4y ago

I'd suggest anyone with a passing knowledge of calculus, complex numbers, and vectors to sit through Leonard Suskind's lectures on quantum gravity. This one was good and wouldn't need the calc/math background, I think: https://www.youtube.com/watch?v=-OkwGDKoY0o https://www.youtube.com/watch?v=-OkwGDKoY0o . But YT is full of actual physics lectures and sitting in on them is pretty approachable with that calc/math background. I think they give an interesting comparison to these popular pieces on particle physics. You might not understand everything the way a physics college student should, and that's ok because you aren't one. But I bet you walk away knowing quite a bit more than you suspect and you can always replay them. Pop-sci pieces tend to portray the universe as just a bunch of particles interacting in odd/spooky ways. It's a little reductive and sort of enshrines entanglement and similar concepts as unknowable at times. I skimmed this and it seems to spend a lot of time on spin 0 particles. Who knows, maybe that's a constraint from ER=EPR? But I didn't feel like it really conveys much about Higgs. (Which would serve a purpose - "oh you can't know it so please come back for next installment in my series of 10 books describing it." I don't think any authors actually set out with that as a goal, explicitly, but they could do a better pointing out where to go for further, more complicated edification. That sort of thing could shoehorn new talent into science.)

dools 4y ago
I watched every single one of the 163 lectures in that series. They're all amazing, and surprisingly addictive. As one YouTube commenter put it so aptly, I always looked forward to "snack time with Lenny".
- abecedarius 4y ago
  Where is this series? The youtube link above seems to be to a standalone lecture. Trying the search terms from this discussion found two other standalone lectures. Is there some UI element on youtube that I'm missing that should make this obvious?
  - danbruc 4y ago
    The Theoretical Minimum [1] [1] https://theoreticalminimum.com/courses https://theoreticalminimum.com/courses

Scubabear68 4y ago

Interesting article, I think I actually understand a lot more than I usually do with physics articles. This quote stood out though. I lol’d: “The Higgs field, on the other hand, is just as spinless as the Higgs boson. Like a college senior sitting forlorn in a career counselor’s office, it has no direction”.

nyc111 4y ago

Were there any other observations of this particle after its discovery, do you know? Is it rare, or is it commonplace?

denton-scratch 4y ago
> Is it rare, or is it commonplace? From my understanding (/me not a physicist), it is rare. It's created only in high-energy situations, and decays extremely quickly. In the very beginning, there were a lot of them, but not for long. I gleaned from the article that the field is everywhere; I think it's correct to say that all fields are everywhere, but according to the article the Higgs field is distinctive: "The Higgs field has a nonzero vacuum expectation value throughout all of spacetime, meaning there is always some value associated with it, even when no Higgs particles are present." I guess, FSVO "present". If there were no Higgs particles anywhere, would the Higgs field disappear? I have no idea.
- denton-scratch 4y ago
  (replying to self - sorry) > If there were no Higgs particles anywhere ...which is counterfactual, if you mean "anywhere in spacetime", because there were a lot of Higgs particles, at the very beginning; and those particles exist in spacetime. If there are no Higgs particles in spacetime, that's a different Universe. I guess (/me not a physicist).
- prox 4y ago
  I always have trouble imagining the fields. Are they like Photoshop layers that work in the background?
  - danbruc 4y ago
    Those fields are a mathematical tool to describe what is going on in a specific way - for example making the local character of particle interactions obvious - but there is no evidence that there are actually any fields. Quite the opposite, a good reason to doubt that those fields are real is that they have Gauge redundancies, i.e. one physical state has several different mathematical representations.

1-6 4y ago

It's a good topic to ponder the existence of intelligent design.

shsbdncudx 4y ago
nah

kytazo 4y ago

As well as punching holes in the time space continuum

anthonyfantango 4y ago

[flagged]