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Comment by grabcocque | Hacker News Reader

I have to admit, I rather admire their putting a brave face on things, with their mildly-too-insistent claim that the LHC is vital for finding new physics despite the increasing likelihood it's not going to find any.

In that sense the LHC is a political failure, because it has failed at its primary political job, which is to make the argument for an even bigger collider.

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You know, it's ok not understand much about high energy physics, it's a complicated and somewhat obscure field. It's ok not to understand about what's already been achieved at the LHC, and what might still be over the decades.

What's not ok is to pontificate from that seat of ignorance.

How'd it fail at it's primary task? Wasn't the Higgs a big part of that? Or is the argument that is hasn't found anything outside of the standard model?

It succeeded at its primary task, and the Higgs was a big part of it. Its still doing its job, so give it time. Finding nothing can often be just as important as finding something unexpected.

> Finding nothing can often be just as important as finding something unexpected.

From a scientific point you are right. From a political point or the point of securing further funding this statement is (unluckily) wrong.

Not really, the European funding isn’t that relying on new findings.

I think its a fundamental problem with teaching science history. We tend to look at achievements in history as being inevitable, like of course we discovered flight after the locomotive was invented, that's just how it happened! But those discoveries were all a circumstances of chance. If we're going to continue to make progress in science we need to accept that new, groundbreaking discoveries don't happen inevitably, they happen from people doing a lot of the dirty work and from imaginative people putting the puzzle pieces together in new ways. There's no inevitability to discovery.

Mapping an open field fills in just as much paper as if you mapped a busy forest.

I'm not sure what the best way is to convey this idea since people naturally want to find things that are exciting.

I think its a good analogy. Or just talk about the original periodic table. It was put together with many holes, but with the assumption that those elements would later be found and sure enough they were. I suppose scientists of the day could have openly accepted that model and decided there was no reason to prove silicon existed, but I think anyone would see that as silly. Its necessary to prove these things.

The physics community does not consider finding the Higgs new physics. Not finding Higgs would've been more exciting, or a more massive / lighter Higgs, etc. The Higgs showed up exactly as predicted with the predicted mass, so we're stuck with the Standard Model - i.e. no "new physics".

You don't go into an experiment with the goal to find new physics.

And yet, that was precisely one of the stated goals of LHC. Observing things is not a bad way to find new physics: Radiation was observed before there was a theory for it. Electrons were also generated as a "ray" before people had any concept of electrons. We've observed the microwave background without knowing about the big bang, or cosmic expansion.

Most new physics starts out as experimental observations. Einstein's theory of relativity is one of the amazing (partial) exceptions.

You can search for it at any time. But how can you state you will find it when you don't know if it's there?

I don't think LHC can be considered a failure on that basis.

Well, I don't know if the LHC is a vital instrument but it will certainly decide were the community of particle physics will go after the plug is pulled on it.

The little I know about is that the LHC is an hadron collider (of course, duh), which means the collisions are not as "clean" as they were with the LEP collider, because the energy is not "deposited" on elementary particles like electrons but on composite hadrons. Which apparently makes things more complicated when it comes to know exactly how the energy is distributed inside the hadrons when they collide...

I'm not sure, I'm not an expert :) I've read that the next collider should use electrons again for collisions, up to 1 TeV or more. Maybe using linear accelerators...

Even if the analogy is not very good it's a little bit like the James Web space telescope, it will open new horizons and open the way for more precise exploration with 50m-class optically stabilized terrestrial telescopes... Just like actual 10m-class telescopes have studied Hubble discoveries in more details.

I see the LHC the same way. The results they will gather from it will decide what to explore next, with more a "precise" collider using leptons and "clean" high energy collisions.

Maybe I'm wrong though. On the political side of thing, sure, it's a costly adventure but I'd rather see money spent on those big scientific project than throwing money at military spendings and engage in useless and illegal wars.

That doesn't mean we can't debate big scientific project. ITER is also a monstrous one when it comes to budget and is even more risky because of the disruptions problem when it comes to confined unstable plasmas in a Tokamak chamber. An apparently 70 years old unsolved problem. Some physicists have warned about powerful disruptions, because of the size of ITER and induced currents in it, potentially harmful for the installation and the people that will work on it if the Tritium breeding blankets are destroyed...

Still, it will be made. And an even bigger experimental reactor is planned, DEMO, that will cost even more. I'm more sceptic about ITER than the LHC...

None of that makes any sense.

You're jumping the gun a bit there. The general purpose experiments have only collected O(1%) of their eventual datasets.

I know what you intended, but technically O(1%) == O(100%) == O(5000%)

It's common in particle physics to express base-10 order of magnitude using this notation. I'm unfamiliar with how it's used elsewhere.

I'm guessing shmageggy thought the notation was Big-O notation. It's a bit of CS notation that defines an upper bound on the number of operations for an algorithm as a function of input size.

I don't know enough about particle physics to know whether you and him/her are even remotely close to saying the same thing.

I did. I've never seen it used in another way. TIL

It's math notation invented for analytic number theory that got popularized in CS by Donald Knuth.

By definition, constant (nonzero) arguments denote the same class, so using constants different from 1 isn't really useful. However, the O stands for 'order' or 'order of', and it sometimes gets (ab)used to denote orders of magnitude (eg powers of 10) of finite values instead of limiting behaviour of functions.

In computer science it's used to express asymptotic behaviour. This suppresses lower-order terms and constant factors, so O(2n + log(n)) = O(n). The most common ones used are upper bounds O(•), asymptotically equal behaviour θ(•), and lower bounds Ω(•).

If you're a physicist, you've probably seen it used as the final term of Taylor expansions. That's the proper usage, whereas the usage above is an abuse of notation insofar as (nonzero) constant arguments are equivalent.

LHC is a science experiment. Its job is to, first, check older results [1], and second, put nature to the test in a well-motivated and important way. In particular, LHC is the Higgs hunter, a messy [2] pathfinder before a precision Higgs-studying tool. It succeeded at that job [3].

That LHC has found no new physics beyond the standard model is not a failure. Finding nothing where you thought you might find something is as useful as finding something. If anything, it is more interesting, as it means there is still far more to be learned.

Politics are about people. The science case is a driver for the political case, but it generally takes a backseat to other goals when funding is at hand. First, science keeps us sharp. It pushes harder on materials and technology than anything ever done. An investment in science is also an investment in the entire science supply chain. The recent explosion of quantum-computing hardware investment has only been possible because scientists have built and sustained the tooling and companies that manufacture the necessary subcomponents at a reasonable cost.

More important, it teaches us how to learn; our most important product as scientists is our students. Students keep the field alive, yes, but most students take their new skills, knowledge, and curiosity with them to share outside of academia. Furthermore, governments support scientists to retain the skills for when they are needed by the populace in general; when the Fukushima accident occurred, our laboratory dropped everything it was doing in order to focus on atmospheric monitoring [4].

Finally, the fundamental knowledge we glean from each halting step forward moves us forward as a species. The device on which you are reading this text is the aggregate product of millennia of fundamental research and refinement.

LHC, at least from my outside perspective (I would benefit personally if less money were directed to colliders), has been well-run, successful, and worth the price, both scientifically and politically.

Where we go next is an interesting question -- I'd place my money on exotic accelerator technology. The detectors are wonderful, and linear accelerators are the century-scale path forward. The trick is finding a revolutionary new accelerator idea.

[1] Which it did beautifully. Really beautifully, and really fast. Look at Figure 3: http://lss.fnal.gov/archive/test-fn/0000/fermilab-fn-0923-cm...

[2] Protons are full of quarks and gluons, so when they collide, it's difficult to know which component hit which other component. Lepton-antilepton colliders, on the other hand, are harder to build, but extremely clean.

[3] There is one Higgs. Its mass is 125.09 ± 0.24 GeV. Its width is less than 1.7 GeV. It is the first fundamental scalar particle known to man. http://pdg.lbl.gov/2016/tables/rpp2016-sum-gauge-higgs-boson...

[4] https://arxiv.org/abs/1103.4853 , https://www.npl.washington.edu/monitoring/node/1

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