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Experimental particle physicist here. It's just hard. I measured the electron's vector coupling to the Z boson at SLAC in the late 1990s, and the answer from t
by mattlangston 8mo ago
Experimental particle physicist here. It's just hard.
I measured the electron's vector coupling to the Z boson at SLAC in the late 1990s, and the answer from that measurement is: we don't know yet - and that's the point.
Thirty years later, the discrepancy between my experiment and LEP's hasn't been resolved.
It might be nothing. It might be the first whisper of dark matter or a new force. And the only way to find out is to build the next machine. That's not 'dead', that's science being hard.
My measurement is a thread that's been dangling for decades, waiting to be pulled.
- sashank_1509 8mo agoWhat would the cost of the “next machine” be? Is it going to be tens of billions or can we make progress with lesser money. If it is going to be tens of billions, then maybe we need to invest in engineering to reduce this cost, because it’s not sustainable to suspend thirty years, tens of billions for every incremental improvement.
- sigmoid10 8mo agoThis kind of slow, incremental improvement that costs tens of billions of dollars and takes decades gave us the microchips that ultimately enabled you to type this comment on your phone/computer. The return on that investment is obvious. But it is not just about making money: The entire field of radiation therapy for cancer exists and continues to improve because people figured out ways to control particle beams with extreme precision and in a much more economical way to study particle physics. Heck, commercial MRIs exist and continue to improve because physicists want cheaper, stronger magnets so they can build more powerful colliders. What if in the future you could do advanced screening quickly and without hassle at your GP's office instead of having to wait for an appointment (and possibly pay lots of money) at an imaging specialist center? And if they find something they could immediately nuke it without cutting you open? We're talking about the ultimate possibility of Star Trek level medbays here. Let the physicists build the damn thing however they want and future society will be better off for sure. God knows what else they will figure out along the way, but it will definitely be better for the world than sinking another trillion dollars on wars in the middle east.
- brazzy 8mo ago> This kind of slow, incremental improvement that costs tens of billions of dollars and takes decades gave us the microchips that ultimately enabled you to type this comment on your phone/computer. No. These two cases are absurdly different, and you're even completely misunderstanding (or misrepresenting) the meaning of the "tens of billions of dollars" figure. Microchips were an incremental improvement where the individual increments yielded utility far greater than the investment. For particle physics, the problem is that the costs have exploded with the size of facilities to reach higher energies (the "tens of billions of dollars" is for one of them) but the results in scientific knowledge (let alone technological advances) have NOT. The early accelerators cost millions or tens of millions and revolutionized our undestanding of the universe. The latest ones cost billions and have confirmed a few things we already thought to be true. > Let the physicists build the damn thing and future society will be better off for sure. Absolutely not.
- Iulioh 8mo agoI'm torn between "yes, these experinets are way too expensive and the knowlage is too niche to be really usefull" and "We said this about A LOT and we found utility in surprising ways so it could be a gamble worth taking" That's the problem with cutting edge reaserch....you don't even know if you will ever needed it or if a trilion dollar industry is waiting for just a number to be born
- brazzy 8mo agoYes, we don't really know. But at some point the gamble is just too big. Because the costs aren't just numbers. They represent hundreds or thousands of person-years of effort. You're proposing that a large number of people should spend their entire lives supporting this (either directly as scientists, or indirectly through funding it) - and maybe end up with nothing to show for it. And there's the opportunity costs. You could fund hundreds of smaller, yet still substantial scientific efforts in many different fields for the cost of just one particle accelerator of the size we think is sufficient to yield some new observations.
- 8mo ago
- raverbashing 8mo agoThe next machine is not necessarily a longer LHC There are talks of a Muon collider, also there's a spallation source being built in Sweden(?) and also of an electron 'Higgs factory' (and while the LHC was built for the Higgs boson it is not a great source for it - it is built as a generic tool that could produce and see the Higgs)
- ForgotIdAgain 8mo agoI think that engineering progress made while building those machines are maybe more relevant for practical technical development than the discovery they make.
- api 8mo agoBetter superconductors here. Would you like a $20 MRI down at your local drug store to detect cancer at early stage 1?
- amanaplanacanal 8mo agoThe problem isn't the cheaper MRI. The problem is the expert that needs to interpret the results. Detecting millions of cancers that don't actually exist doesn't help anybody.
- api 8mo agoThis is a problem domain AI is good at. Have AIs do first-pass, then when they flag something an actual doctor reviews it. Then if they concur it goes to your doctor, who knows you, who can review it.
- toast0 8mo agoSpending tens of billions every thirty years is pretty sustainable actually. "Fundamental Research" may or may not pan out, but the things that happen along the way are often valuable... I don't think there's any practical applications related to generating Higgs Bosons, but it's interesting (at least for particle physicists) and there's a bunch of practical stuff you have to figure out to confirm them. That practical work can often generate or motivate industrial progress that's generally useful. For example, LHC generates tons of data and advances the state of the art in data processing, transmission, and storage; that's useful even if you don't care about the particle work.
- ajam1507 8mo agoYou could say the same thing about the world wars or porn. Any human pursuit taken to an extreme can produce knock-on effects, that isn't an argument in a vacuum to continue to fund any one area.
- toast0 8mo agoSpending tens of billions every 30 yesrs on world wars would be pretty awesome. Much better than what we currently spend. Porn seems to be sustainably self funding; no need for government stimulus.
- ajam1507 8mo ago> Porn seems to be sustainably self funding; no need for government stimulus. Only because you haven't seen the plans for the Large Hardon Collider
- snowwrestler 8mo agoIn the scope of international cooperation, tens of billions of dollars is not very much money. For context, the U.S. economy generates $10 billion every ~3 hours. One private company, Google, spends $10 billion in about 2 weeks. So look at it this way. Let’s take a bunch of the smartest people alive, train them for decades, give them a month of Google money, and they’ll spend 30 years advancing engineering to probe the very fabric of reality. And everything they learn will be shared with the rest of humanity for free. Sounds like a pretty good deal to me.
- aleph_minus_one 8mo ago> Let’s take a bunch of the smartest people alive, train them for decades, give them a month of Google money Unpopular opinion: Google makes an insane amount of money, so they can afford this salary. The CERN (or whatever your favourite research institute is), on the other hand, is no money-printing machine.
- alphawhisky 8mo agoEvery step towards understanding subatomic physics is a step towards cold fusion. The second we're able to understand and capture this energy, money literally doesn't exist. Infinite energy means infinite free energy, which would also abolish money from a fundamental market value perspective. I'll continually preach that we need to plan for this economically as a species because none of our current government or economic systems will survive the death of scarcity.
- aleph_minus_one 8mo ago> The second we're able to understand and capture this energy, money literally doesn't exist. Infinite energy means infinite free energy[.] Similar statements were already claimed about nuclear fission power plants in the 70s.
- pixl97 8mo agoAnd your point is? Sometimes we make predictions that take hundreds of years to be turned into products.
- Uehreka 8mo agoThere are people in this thread saying tens of billions isn't that much in the long term (I'd agree) but there's a bigger point that comes into play whatever the price: The universe doesn't care if exploring it is expensive. You can't make a "that's not sustainable" argument to the universe and have it meet you half way. And that's who you're arguing against: not the scientists, the universe. The scientists don't decide how expensive future discoveries will be.
- kakacik 8mo agoIts a clickbait article name (from otherwise good place), of course its not dead... we are now getting understanding of all things we don't know yet, discrepancies like yours, unified theory and so on. Everybody knows we are not there yet and how the final knowledge set will look like, if its even possible to cover it (ie are quarks the base layer or we can go deeper, much deeper all the way to planck scales? dynamics of singularities etc)
- hippich 8mo agoIs it hard as in: 1) we know what to do, but it is expensive 2) we don't know what to do exactly, but many more people involved can increase search speed, so just need more people 3) it is purely sequential problem, and therefore it takes a lot of time
- samus 8mo agoA combination to some degree. Scientists yearn to stumble upon something hitherto unexplainable that requires a new theory or validates or definitely rules out some of the more fringe theories. While other natural sciences often suffer from an abundance of things that "merely" need to be documented, or where simulation capability is the limit, particle physics is mostly based on a theoretical framework from the middle of the 20th century that has mostly beth explored. Getting ahead in particle physics comprises measuring many arcane numbers to as high precision as possible until something doesn't line up with existing theories or other measurements anymore. More people could help with brainstorming and measuring things that don't require humongous particle accelerators.
- aleph_minus_one 8mo ago> Scientists yearn to stumble upon something [that] definitely rules out some of the more fringe theories The existing measurements at CERN ruled out a lot of the "more natural" variants of string theory. Until now this insight has not lead to a big scientific breakthrough.
- KolibriFly 8mo agoSo, if the answer were obvious or quick, it wouldn't be worth building machines that take decades to design
- orbifold 8mo agoI guess we will find out in 20+ years once the next electron positron collider at CERN has been build
- htx80nerd 8mo ago>"It might be the first whisper of dark matter" Come now.
- mattlangston 8mo agoFair - that sounds hyperbolic. But my point is specific: if the weak mixing angle is shifted from the Standard Model value, one of the standard explanations is a heavier cousin of the Z boson mixing in. Many of those models naturally include a dark matter candidate. I didn't mean to imply 'we found dark matter' — it's that the theories which could explain the discrepancy often come with one attached.
- alpineidyll3 8mo agoBut.. are you saying your vector coupling isn't explained by the existing standard model, that the measurement lacked sufficient resolution, or that existing calculations don't agree with your measurement?
- mattlangston 8mo agoGood question. It's mostly the third — but let me unpack that. The Standard Model predicts a specific value for the weak mixing angle, which determines the electron's vector coupling. My measurement at SLAC, along with other SLD measurements, consistently preferred a slightly different value than what LEP (the European competitor experiment) found using a different technique. The key word there is "different technique." SLD used a polarized beam of electrons — a completely novel approach at the time — which gave us direct access to the left-right asymmetry without needing to untangle final-state effects. LEP extracted the same parameter from b-quark forward-backward asymmetry. Two fundamentally different methods probing the same physics, with different systematic exposures, giving different answers. Both experiments had good resolution. We spent enormous effort characterizing the systematics, and they're small compared to the statistical uncertainty. But the two most precise determinations of this parameter disagreed at roughly the 3-sigma level — and that disagreement has never been explained. The world average splits the difference, and the Standard Model prediction is consistent with that average, so you could say "the SM is fine" if you squint. But nobody knows why the two experiments don't agree with each other. It could be an unidentified systematic error in one experiment. It could be that something beyond the Standard Model is subtly shifting one measurement and not the other. That ambiguity is exactly what makes it a "dangling thread" rather than a resolved question.