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by levi_n 1478 days ago
> ...than by handing that money to the old guard which has produced nothing of significance for the last two generations.

Genuine question from an ignorant layperson: was confirming the existence of the Higgs boson not significant?

3 comments

(Former PhD student in Particle Physics Pheno here, far from an expert)

Of course it was a significant discovery, but honestly it would have been a far more interesting if we detected literally nothing. It's kind of weird because it was marketted as a success story to the public (and don't get me wrong, it was) but theorists were very confident that it was there by 2012. Thus far, it behaves exactly as expected according to the standard model and that is very dull.

HEP would have been left in a very funny position if we didn't find it. No Higgs Boson would have been fascinating from a theory perspective, but good luck trying to get funding for a new collider when you found nothing with the old one.

Not a particle physicist, but I think the entire history of human scientific discovery is set again that proposition. Namely: (1) that we have a fundamental theory that describes the Universe; (2) that it is within our technical capability to experimentally verify the reality of that theory; and (3) we choose not to do so.

It's easy to monday-morning quarterback a result that was successful and unexciting, but imagine how intolerable the world would be if we'd chosen not to verify it.

Information is a measure of surprise: we should choose to verify our predictions; but it's disappointing when our predictions turn out to be correct.

We want our best predictions to be proven wrong, since we would learn a lot.

I get where you're coming from, but at the same time, we have to KNOW things before we can continue to theorize about new things. If you keep theorizing on things that turn out to not be true, then it's just a waste of everyone's time. Find things that are true, theorize on the next step, test, prove/disprove, lather, rinse, repeat.

Just coming up with stuff and disproving it isn't always "learning a lot", it's just showing how bad we are at logically thinking about the next step.

> Just coming up with stuff and disproving it isn't always "learning a lot", it's just showing how bad we are at logically thinking about the next step.

That's why I said "our best predictions"; as in, what we actually think is the case (and would put money on).

If "information is a measure of surprise", then you don't want every prediction to be wrong. You want every prediction to have a 50% chance of being wrong. Half of your experiments should be failures.
I don't understand this logic at all. At those odds, you're just guessing like flipping a coin. An inferred prediction should have a higher success rate. We look at the data we do know, we see what holes are there, and then make predictions based on all of our previous knowledge. The fact that the previous knowledge allows us to make more accurate predictions shows we have a better understanding of the subject than just random coin flips.
Yes and, riffing on your clarification, maybe also make a distinction between hypothesis and prediction. Both are based on models, but a hypothesis hasn't been experimentally validated yet.
> It's easy to monday-morning quarterback a result that was successful and unexciting, but imagine how intolerable the world would be if we'd chosen not to verify it.

I once read a paper complaining that the most of psychology experiments are trivial in the sense that their results are predictable in advance. It is like all people know that angry people tend to make other people angry and so if angry person try to communicate then oftentimes communications ends with a conflict. What the point of making an experiment from this?

I'm not sure how much of a psychology fall victim of this, but sometimes I read a paper and think that I've found one more example of this. I personally get nothing from reading such a paper. I can get some ideas while reading about methods researchers used, but it means that the paper is not about how human mind works, but about how to measure psychological phenomena, or how to conduct an experiment. I bet that the most interesting part of the hypothetical paper with angry communicating people would be the trick researchers used to make people angry without violating ethics.

There is some value in experiments that try to prove something that everyone knows already, but not much of a value. So the question is: is it ok to spend $10G to conduct such an experiment?

I’m pretty sure there remains a discrepancy between the predicted mass of the Higgs boson and the measured mass in experiments. Is this resolved then?

I was under the impression that this was a smoking gun for something being off with the theory, a bit like the ultraviolet catastrophe that led to QM or the orbital aberration that was resolved by GR.

> I’m pretty sure there remains a discrepancy between the predicted mass of the Higgs boson and the measured mass in experiments. Is this resolved then?

Sort of.

The higgs boson mass is a parameter to the Standard Model. As far as the Standard Model is concerned, that is the end of the story. There are just a series of constants need to be fitted to data in the Standard Model and that's one of them.

However, the "problem" is why ~125GeV. If there are extremely high energy particles (which are expected in a Grand Unified Theory), then corrections to the Higgs mass would be enormous. This is a fine tuning problem where we arbitrarily tweak those corrections such that we magically end up at 125GeV. Supersymmetry and other Beyond Standard Models look to 'fix' this, and that's where my knowledge ends.

Honestly, when I was doing my PhD I took the pragmatic view on this. Trying to infer things at energy scales we can't probe struck me as more as a mathematical exercise than Physics. Many, many people would disagree with that though (and staked their careers on it).

> However, the "problem" is why ~125GeV. If there are extremely high energy particles (which are expected in a Grand Unified Theory), then corrections to the Higgs mass would be enormous. This is a fine tuning problem where we arbitrarily tweak those corrections such that we magically end up at 125GeV.

When I was undergraduate at CERN summer school program I got that this was one of main themes to justify existence of SUSY. However I am still puzzled even after having obtained a PhD (condensed matter) how does this arbitrary tweaking of corrections does look like.

Is it simply unwillingness to accept for world as we live know some parameters of the world like particles masses are not that independent from each other?

There are other problems with the theory too, they probably weren't solved perfectly by whatever SUSY model your supervisor was working on so they got less attention.

But ultimately, yes. The entirety of modern physics is largely borne out of the unwillingness to accept the the world is simply as it appears and that there's no deeper unifying principles.

> Is it simply unwillingness to accept for world as we live know some parameters of the world like particles masses are not that independent from each other?

Based on what I understood from Sabine Hossenfelder's writing, yes, that is a big chunk of modern physics. One example is "the naturalness problem", that some base parameters of the SM are orders of magnitude larger or smaller than other ones - which is of course entirely possible as a fact of nature.

In theory, theory and practice are the same. In practice, they are not.
Yogi Berra

I was thinking the same thing! Haha

>Of course it was a significant discovery, but honestly it would have been a far more interesting if we detected literally nothing.

Well you would have needed the LHC to confirm that, too, right? As a totally uneducated person just remembering media and online discussion about it at the time, I think the most interesting possibility was the detection of entirely new particles, which didn't happen.

And in the run-up to the LHC, I think there was a lot of hope in the possibility of finding stuff, but maybe there's not as much hope now.

Well that's sort of my point. In the media there was a lot of excitement about detecting supersymmetry with a whole array of new particles. When talking to the general public, it's easy to drum up the excitement by saying we're going to find lots of stuff. On the other hand, wheeling out a Physicist in front of the public and say "Finding nothing would be the most exciting outcome!" is a much harder sell, even though it is arguably true.

Which is the most exciting outcome between SUSY and absolutely nothing is very much debatable. However, I really can't stress how big an outcome it would have been if we didn't detect the Higgs. Generating a mass term for the W and Z bosons which is gauge invariant is hard. Without the Higgs mechanism, all the gauge bosons should be massless and yet the W and Z are very heavy. It wouldn't just be the case of the model doesn't work in some cases (massive neutrinos, dark matter candidate etc), you might as well throw the whole thing in the bin.

Edit: Typo

In a scientific sense - no. It was predicted, it was found. No theories needed rewriting.

Significant would have been if they'd failed to find it.

I would claim finding it was equally significant. Theory is not reality but just a model until verified. I know there is a trend in physics where computing is supposed to suffice without actually verifying anything but that is just wrong - I presume this notion is driven by the incentives to focus on publishing more than tedious collaboration.
I agree. But isn't the issue that there is not really anything like Higgs for a new larger collider?
So finding Black-holes is not significant because it was already predicted?

And btw there is so much money around...we should not fight against different project but the spending that goes into science itself. LHC and NASA is really just a small drop compared to military spending (in the US).

https://twitter.com/WillPVGreen/status/1363179862706503681/p...

Why hello again, tragedy of the commons!

Modern monetary theory is its own can of worms, but justifying massive spending in one area because of even more massive spending elsewhere isn't solving anything.

But:

https://interestingengineering.com/these-7-cern-spinoffs-sho...

And i think the ISS was still much more expensive (especially over the years) then LHC/Atlas etc.

Those "practical" results were all due to the spending on technology. None were due to advances in physics, as far as I can tell (that website seems designed to obfuscate not illuminate)
>spending on technology

Like the Moon-landing right? None were due to advances in landing on the moon.

Did it change your life in any way?

(Most times, people don't know how to judge that, but high-energy physics really didn't impact anything.)