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Did the W-boson just “break the standard model”?

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Re: Did the W-boson just “break the standard model”?

#201

Post by gizmo686 »

pdonis wrote: post #195
gizmo686 wrote: post #141

Earlier quoted context omitted.

Was the orbit of Mercury (or any other astronomical observations) important for the discover of Relativity. My understanding was that experimental impetus for relativity was the Michelson–Morley experiment, which was an in-lab experiment, not an astronomical observation. General relativity was then developed on a purely theoretical basis. That it was able to explain Mercury's orbit was a nice bit of empirical confirm…

> Was the orbit of Mercury (or any other astronomical observations) important for the discover of Relativity. For general relativity, yes. > My understanding was that experimental impetus for relativity was the Michelson–Morley experiment This was one of the results that pointed the way to special relativity. It had nothing to do with general relativity. > General relativity was then developed on a purely theoretical…

> No, it wasn't. There was a huge body of experimental evidence already about gravity. It was true that all of that evidence, except for the anomalous precession of Mercury's perihelion, could be explained by Newtonian gravity; but general relativity, as a proposed new theory of gravity, had to also account for all of that experimental evidence. In other words, in the appropriate limiting case (weak fields and low speeds compared to the speed of light), general relativity had to reproduce all of the correct predictions of Newtonian gravity. That was a huge, and very important, experimental constraint.

Yes. I assumed that reproducing Newtonian gravity in the classical limit would be considered theoretical, as we had a solid theoretical understanding of Newtonian physics. Implicit in that would be a bunch of empirical evidence; but Einstein wouldn't need to explicitly think about the details of what evidence supported Newtonian mechanics (beyond the general understanding that it was all in the classical limit).

> Not if the differences between its predictions and the predictions of the previous theory (in this case Newtonian gravity) are only measurable in astronomical observations at the time the new theory is proposed.

Such a theory is not "useful", for many definitions of useful. Astronomical observations allowed us to verify Relativity earlier than we otherwise would be able to; but eventually technology advanced to the point where we could conduct satellite based experiments to directly confirm it. The theory was not practically useful until we had this technology.

> Technology can of course be developed on a purely empirical basis, if you're prepared to make a lot of mistakes along the way that you wouldn't make without a good theoretical foundation. If it hadn't been for the knowledge of relativity on the part of the scientists involved, the GPS satellites probably would have been launched without any capability for adjusting their clock rates.

Its not like we launched the entire GPS constellation then just hoped it would work. Before launching the GPS constellation, we launched the experimental Timation satellites to act as a proof of concept. Difficulties with maintaining accurate clocks in orbit would have been noticed then (if not sooner).

Re: Did the W-boson just “break the standard model”?

#202

Post by [deleted] »

evanb wrote: post #117
adrian_b wrote: post #31

Earlier quoted context omitted.

Unfortunately the standard model does not work "extremely well". Even if we suppose that the standard model is completely correct, it does not allow the computation of the majority of the useful physical quantities. What is needed is a model that would be able to compute all the physical quantities that are important in practice, e.g. the masses of all hadrons and of all atomic nuclei, also their magnetic moments, th…

I think your comment is far behind the times. Directly from QCD we have: computed the low-lying parts of hadronic spectrum, computed the proton-neutron mass splitting, made _pre_dictions about hadronic masses that were then found at the LHC, computed the nucleon axial coupling g_A, vacuum polarization and light-by-light, and so on. It requires supercomputers. But so what? Nobody promised that physics should be easy.…

[deleted]

Re: Did the W-boson just “break the standard model”?

#203

Post by adrian_b »

evanb wrote: post #117
adrian_b wrote: post #31

Earlier quoted context omitted.

Unfortunately the standard model does not work "extremely well". Even if we suppose that the standard model is completely correct, it does not allow the computation of the majority of the useful physical quantities. What is needed is a model that would be able to compute all the physical quantities that are important in practice, e.g. the masses of all hadrons and of all atomic nuclei, also their magnetic moments, th…

I think your comment is far behind the times. Directly from QCD we have: computed the low-lying parts of hadronic spectrum, computed the proton-neutron mass splitting, made _pre_dictions about hadronic masses that were then found at the LHC, computed the nucleon axial coupling g_A, vacuum polarization and light-by-light, and so on. It requires supercomputers. But so what? Nobody promised that physics should be easy.…

The values that you mention, e.g. the proton-neutron mass splitting, have been computed only with a precision much lower than such values can be measured experimentally.

That means that such computations have little, if any, practical importance.

With the current QCD, it is not possible to compute the ratio between the mass of the neutron and the mass of a proton with a useful precision. The mass ratio between the proton and the electron or the mass ratios between light nuclei or their magnetic moments are even less possible to compute.

QCD would become a useful theory only when it would be possible to compute things like the probability of fusion of light nuclei with a precision good enough to eliminate the need to measure such values experimentally.

QCD would need revolutionary improvements to achieve such goals.

Supercomputers are not enough for a progress in this domain. Different solving methods must be discovered.

Re: Did the W-boson just “break the standard model”?

#204

Post by pdonis »

gizmo686 wrote: post #201
pdonis wrote: post #195

Earlier quoted context omitted.

> Was the orbit of Mercury (or any other astronomical observations) important for the discover of Relativity. For general relativity, yes. > My understanding was that experimental impetus for relativity was the Michelson–Morley experiment This was one of the results that pointed the way to special relativity. It had nothing to do with general relativity. > General relativity was then developed on a purely theoretical…

> No, it wasn't. There was a huge body of experimental evidence already about gravity. It was true that all of that evidence, except for the anomalous precession of Mercury's perihelion, could be explained by Newtonian gravity; but general relativity, as a proposed new theory of gravity, had to also account for all of that experimental evidence. In other words, in the appropriate limiting case (weak fields and low sp…

> I assumed that reproducing Newtonian gravity in the classical limit

GR itself is a classical (i.e., non-quantum) theory. The Newtonian limit of GR is not usually considered a "classical" limit, just a weak field, slow motion limit.

> would be considered theoretical

Ok, then we just have different definitions of "theoretical". To me, having to account for a mass of experimental data is an experimental constraint. It might be easier for a theory to meet it if the theory can be shown to reduce in an appropriate limit to a previous theory that accounts for all that data.

By contrast, for researchers investigating possible quantum theories of gravity, any quantum constraints on their theories can only be theoretical, since we have no experimental data at all on quantum aspects of gravity. But to me, the fact that a quantum theory of gravity has to account for all of the classical experimental data on gravity is an experimental constraint (which any such theory would presumably meet by reducing to GR in the classical limit).

> Such a theory is not "useful", for many definitions of useful.

No theory is useful for all definitions of useful.

> Before launching the GPS constellation, we launched the experimental Timation satellites to act as a proof of concept.

As I understand it, the Timation satellites did not keep independent time using clocks aboard the satellites. They just re-broadcast time signals from the ground. One of the major difficulties with getting GPS operational was the additional complexity involved in having independent clocks on the satellites that would keep their own time, with only periodic updates from the ground. And one of the major issues with that was that many non-scientists involved in the GPS project did not understand relativity and did not believe that the "natural" clock rates of the clocks on the satellites would be different from those of ground clocks, so some kind of adjustment would have to be made. And there was no data from previous projects to convince them since the relative clock rates of previous satellites vs. ground clocks had not been measured. If the non-scientists in the GPS project had not given in to the scientists who wanted to include the capability for adjusting the clock frequency in the initial set of GPS satellites, those satellites would indeed have been useless.

Re: Did the W-boson just “break the standard model”?

#205

Post by noizejoy »

gizmo686 wrote: post #79
TheOtherHobbes wrote: post #72

Earlier quoted context omitted.

As opposed to open season on new theory - or even new kinds of theory. The Standard Model is a bit of a franken-theory of a thing, a kit of parts bolted together in awkward ways. It looks a lot like the pre-quantum ad-hoc theories that attempted to describe quantum effects before QM was invented. It's hard to believe that physics can't do better. But easy to believe that physics won't do better while most of the mone…

That sounds like you are complaining about the amount of investment in experimental physics in general, rather than the LHC in particular. It is true that fundamental physics could use a major breakthrough from the theorists. However, the theorists we do have are desperate for more experimental evidence to help them. Add to that that experimental physics is simply far more expensive then theoretical physics, and it s…

> spending $5 billion to smash protons together

About the same as a the price of a large modern sports club in a top league[0]

[0] https://www.theguardian.com/football/2022/apr/29/chelsea-sir...

Re: Did the W-boson just “break the standard model”?

#206

Post by lisper »

ravi-delia wrote: post #172
lisper wrote: post #43

Earlier quoted context omitted.

Falsifying supersymmetry is like falsifying Ptolemaic epicycles. You can never falsify it with data because epicycles can always be constructed to fit any data set [1]. Likewise, a sypersymmetric theory can be constructed to fit any set of parameters. But fitting the data is not enough. You have to fit the data with substantially fewer parameters than data points. That's the challenge. [1] https://www.youtube.com/wat…

I feel like that example assumes the conclusion. A better analogy would be "spinning objects theories". It's a category so broad you could always find something which works, but since it's not really thought of as a particular solution, it isn't so vulnerable to overfitting. Epicycles were bad largely because they gave a false impression of closing in on reality; every new round of additions consisted of smaller and…

What on earth is a "spinning object theory"???

Re: Did the W-boson just “break the standard model”?

#207

Post by Maursault »

fhars wrote: post #163
gizmo686 wrote: post #141

Earlier quoted context omitted.

Was the orbit of Mercury (or any other astronomical observations) important for the discover of Relativity. My understanding was that experimental impetus for relativity was the Michelson–Morley experiment, which was an in-lab experiment, not an astronomical observation. General relativity was then developed on a purely theoretical basis. That it was able to explain Mercury's orbit was a nice bit of empirical confirm…

No, there was basically no empirical input into the development of special relativity either, Michelson-Morley was already perfectly explained by Lorentz contraction caused by movement of matter through the ether. What special relativity did was solve the purely theoretical contradictions between Newtonian mechanics and Maxwell's electrodynamics (hence the title of Einstein's paper "On the electrodynamics of moving b…

> No, there was basically no empirical input into the development of special relativity either

There is a myth of Einstein that just isn't credible, which is that Einstein, while working as a patent clerk just came up with Special Relativity out of the blue without anyone's input, without the benefit of history.

But Special Relativity was in the air. Henri Poincare was already writing about relativity, and so were others in years previous to Einstien's publication. If Einstein hadn't published when he did, someone else would have within a few years at best.

Einstein was amazing, also, just a man, but definitely was not the myth taught to us in elementary school, like Abe Lincoln carrying an ax, these are childish and frankly false ideas. Einstein stood on the shoulders of giants, and there was massive amounts of empirical evidence for Special Relativity going back thousands of years, really, billions.[1]

[1] https://en.wikipedia.org/wiki/History_of_special_relativity

Re: Did the W-boson just “break the standard model”?

#208

Post by XorNot »

patrick451 wrote: post #139
XorNot wrote: post #46

Earlier quoted context omitted.

> LHC have absorbed a disproportionate share of these scare resources As opposed to? This sentiment was bandied around a lot before the LHC went online, but no one ever had a proposition of what the alternative was is the goal was to advance fundamental particle physics. You've got exactly 2 ways to probe subatomic interactions: (1) particle accelerator measurement and (2) incidental measurements of high-energy space…

As opposed to funding things that are not particle physics at all. As far as I can tell, knowing that bosons exist has had approximately zero impact on our ability to engineer new stuff. Personally, I'm tired of footing the bill for a field that requires the one of the largest, most expensive experimental systems ever conceived yet seems unable to produce more than useless factoids.

This is just demanding to know where research will lead us, as though it's the tech tree in a 4X game.

You'd be equally opposed to Sabine's alternative since what use is knowing anything about dark matter? For that matter who cares where the universe came from. What have telescopes helped us with lately?

Re: Did the W-boson just “break the standard model”?

#209

Post by rapjr9 »

tambourine_man wrote: post #82
photochemsyn wrote: post #12

Well this is kind of funny and I mostly agree so TLDR: > "I’m afraid all of this sounds rather negative. Well. There’s a reason I left particle physics. Particle physics has degenerated into a paper production enterprise that is of virtually no relevance for societal progress or for progress in any other discipline of science. The only reason we still hear so much about it is that a lot of funding goes into it and so…

Sabine went on full rant/iconoclastic/grudge mode IMO recently. It's a shame, as she a good communicator, but I just see myself skipping her content when it pops up. “I left the field because it's a paper production machine that adds no value to society” without substantiation is simply a frustration ridden meme.

I agree with her, I've been seeing the same problems with the physics community for decades. Everything kind of stopped after Einstein, and in particular I think nuclear weapons scared the heck out of everyone. I have long suspected that physics research since that time has been intentionally limited to "safe" areas like semiconductors, cosmology, and string theory. The old guard essentially decided that having physicists come up with death rays, superbombs, gravity warpers, and space travel was too risky. In the last several years the younger crowd of physicists have been re-examining some of the old physics and finding interesting gaps, so there may soon be much more progress. SpaceX may have found it relatively easy to be inventive in the space transportation arena because governments had final approval on any space projects for decades, leading to the stagnation of rocket development. I think there was a great desire to slow things down and keep technology from progressing faster than society could cope with it. You can argue whether that was good or bad.

Re: Did the W-boson just “break the standard model”?

#210

Post by robonerd »

pa7x1 wrote: post #198
robonerd wrote: post #167

Earlier quoted context omitted.

Maybe she's in it for the fame and money, but I don't think that would make her intentions malicious.

She abuses an information asymmetry and social conventions. Scientific discourse is usually conducted in academic papers, for better or worse this is how the community conducts itself. When she criticizes others work or the usefulness of the fields outside this channel she is addressing as a singular voice the general public. Which gives her voice an outsized presence with a public that is not prepared to engage on e…

If she earnestly believes that particle physicists are lying to the public to get funding, then there's nothing malicious about going to the public and saying this. It makes her essentially a whistleblower, and there's nothing malicious about that. Even if she happens to be wrong, that still isn't malicious intent.

If she's lying, then that's different. But I haven't seen any convincing evidence that she's lying. It's clear a lot of people don't like what she's saying, feel threatened by what she's saying, and think she's wrong. But that doesn't make her malicious.

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