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The Rise and Fall of Supersymmetry
Ethan Siegel at the StartsWithABang blog writes:
"Have you ever wondered why the masses of the fundamental particles have the small values that they do, compared to, say, the Planck scale? Whether the fundamental forces all unify at some high energy? And whether there's a natural, compelling particle candidate for dark matter? Well, in theory supersymmetry (or SUSY, for short) could have solve all three of these problems. In fact, if it solves the first one alone, there will be definitive experimental signatures for it at the Large Hadron Collider. Well, the LHC has completed its first run, and found nothing. What does this mean for theoretical physics, for SUSY in particular, and what are the implications for string theory? A very clear explanation is given here; it might be time to start hammering in those coffin nails."
Is there an xkcd comic that explains this at the level that most of us can understand? Something with an exacerbated physicist trying desperately to explain the experiment with analogies and gestures would be ideal?
My God can beat up your God. Just kidding...don't take offense. I know there's no God.
I'm sure a "very clear explanation" is given, but I'm not going to read something that presents it to me at a rate of one sentence per page.
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
Never mind - the presence of empirical data which tends to place supersymmetry in doubt is enough to convince me that either we need a better theory, or the existing theory needs a major overhaul.
Was Putin to busy conquering to offer up a quote?
That's sort of the point. M-Theory might just be a dead end. If we don't find the supersymmetric partners in the next run of the LHC at the very least string/M theory will need considerable re-vamping if not a total scrapping.
Super!
It's 'its', not 'it's'
"it not coming through with what was hoped"
I think Science is not about confirming what we want to believe, but more just learning how things work.
You're right that the LHC does it's job; the Higgs Boson is one of the century's biggest discoveries. And, incidentally, that confirmation was exactly what many hoped for. And disproving string theory was also something some hoped for.
So I don't understand where the grumpy comes from. It's been a spectacular success.
That's like complaining that the Michelson-Morley failed to measure the presence of the lumineferes ether, something scientists thought was very likely to exist. Science advances when you get a surprising result, not when you see what you expected. If the statistics support this, it is a MUCH more interesting result than finding the Higgs which was pretty much were people expected it.
...is disconfirm our beliefs.
Unlike that apostrophe, which has no clear job there.
Insane in the m-brane.
In SUSY, there is no way to predict the masses of supersymmetric particles, but there is a way to predict a range of values that the mass of the lightest SUSY particle must fall within in order for SUSY to be a valid theory. The range is determined by the mass of the Higgs boson. For small Higgs masses (less than ~100GeV, don't quote me on these numbers as it's been a while) and large Higgs masses ( greater than ~140GeV), the range is very small, and our current colliders would have already disproven SUSY. However, the observed Higgs mass of 126GeV is a sweet spot which allows the mass of the lightest SUSY particle to be far greater than the LHC can produce. It'll take a few more colliders before we can dismiss SUSY completely.
I liked this article. The author did a good job of dumbing things down for us mortals. Super symmetry has been dieing since the day the LHC came online. But I have a problem with:
A lot of people have invested their entire careers in SUSY, and if it’s not a part of nature, then a lot of what they’ve invested in is nothing more than a blind alley. For example, if there is no SUSY in nature, at any energy scale (including the Planck Scale, although this will be a challenge to test), then string theory cannot describe our Universe. Plain and simple.
I seriously doubt many of the geniuses that dedicated their entire lives with Super Symmetry would consider it a blind alley. There's been some amazing math, and amazing theoretical work on it. It's a very very good theory. It's rather clear that this point that it's not correct, but whatever the truth really is (something we clearly haven't even imagined yet) will be helped greatly by the work done by those investigating super symmetry. The Wright Bothers didn't just hop in a plane and fly off... There were mountains of work by thousands of failures that they built their success on.
Thank's, You're cromulence;
Insane in the m-brane.
Insane in the Brane...
I don't really care about this post, but at home I get the old slashdot and at work I get the new (fucked up) slashdot. I don't know why. I have been a slashdot subscriber for a long time, nearly since slashdot started (my user id is 3000, I can't seem to see it anymore since they don't want me or anyone to know anymore). I still like the old slashdot better than the new. Why the fuck does the new management have to fuck things up? They had a good thing going here, why fuck it up?
You just wish your ID was as low as mine! I used to be proud to have such a low id, but not so much now. Slashdot most
What's wrong with electron's orbits synchronizing energy as one? The more mass the more energy as ONE big Unit. I mean; have you ever seen the model of a working atom? How it pulses with each electron's reloving, very realistic I think... OK now imagine all of the similar electron's pulsing orbits locking together (magnetically) synchronizing to become one unified force. That's what holds matter together, like magnetism on a molecular level. Easy as Pi Any electrical theorist will follow what I say right? Why Is It so hard to understand how things work you guys? It's all electon ical. And easy as Einstein. Think about it and go see a model of a moving Atom... It will click.
...without recognizing a +1 funny post when I see one.
"It did it is job..."
What's the problem here?
The interesting thing is that Couder's experiments with silicon walkers that replicate on a macroscopic scale the two-slit experiment require an "ether" substrate. So maybe the ether does exist after all.
Heroes and Villains are the same, its just a matter of perspective.
Abraham Lincoln killed far more than Che, but you have to admit he left some great quotes too.
Except that the higgs boson is real, monopoles habe been artificially created and that you haven't understood anything.
Just shut up.
Not that I know of but since I am an exacerbated physicist how about I try to explain our experiment with analogies and you can just imagine appropriate gestures to go with them? First though I should say that while SUSY is in trouble the article paints an overly pessimistic picture and gets a few things wrong.
The problem SUSY is trying to solve is that nature seems to be performing an amazing balancing act with the Higgs field. Now this is not just some ordinary balancing act that generates a few "oohs" and "aahs" from the audience like Idol Rock. According to the physics we know the chance of the Higgs boson having the mass is does is about one in 10^30. Those are about the same odds as some person winning a national lottery 5 times in a row and getting a lesser prize in the 6th week. By about the third or fourth win the "oohs" and "aahs" are replaced by a call to the serious fraud squad of the local police force with a request to figure out how the person is fixing the results of the lottery because the chance that this person is just "really lucky" are so astronomically small that nobody will believe it is just chance.
This is the situation we are in now with physics and the usual way nature solves balancing problems like this is with a symmetry that requires the balance be perfect. For example it is not just dumb luck that the electrical charge in the universe happens to cancel out so precisely - we were not just "really lucky" with our Big Bang! - there is a symmetry which gives conservation of electric charge which requires that the balance be exact. To solve the problem with the Higgs mass being so tiny the symmetry is called "Supersymmetry" - not because it flies around with a big S on its chest saving us from bad symmetries but because it is an extremely high level symmetry, perhaps even the highest possible in nature. In very simple terms you could describe it as a symmetry between force and matter.
This is also why I would disagree with the article when it says that the LHC must see supersymmtery or else it cannot solve our balance problem. This would be like saying that if you win the lottery twice that's ok but win it a third time and you are automatically guilty of a crime. Winning it 3 times in a row might be very, very unlikely but this is a continuous scale. 10TeV SUSY may be less natural than 1TeV but it is not so incredibly less likely that you know it cannot be right - sometimes 0.1% chances happen e.g. the angular size of the moon being almost exactly the same as the sun on Earth.
Supersymmetry is not a perfect symmetry because otherwise all the super-particles (which have fun names likes squarks, winos and sleptons) would then have the same mass as our Standard Model particles and we would have already seen them. So it has to be broken by some unknown mechanism which gives all the super particles higher masses which is why we have not yet seen them - our colliders do not yet have enough energy.
Another possibility is that the lightest super particle cannot decay. This would give us a high mass, stable particle which is an excellent candidate for dark matter. However this where the article is not correct in saying that the particle should have been seen by direct search experiments because one possibility is that it is a gravitino (a super partner of the graviton). This would mean that it only interacts via gravity and will not be seen in direct search experiments. This would be a real pain for physics because while we would know that we had produced them in the detector (because the other particles we can see will rebound from it) it will be very hard to prove that these were the Dark Matter astronomers see.
Probably out best chance to see supersymmetry, or indeed any new physics, will be the next three year run of the LHC. We will get almost twice the energy and about 5 times the luminosity. Certainly if we do not find supersymmetry or something else then the chances of us every seeing it with the LHC are dramatically lower after this point because increasing numbers of events at the same energy only slowing increase the regions you can search. So fingers crossed!
So according to you backyard hillbilly genius, plasma nuclei (atoms ripped of all electrons) should fall apart? Naaaa. Surprise. They don't.
One forum idiot is shirley (sic) better than thousands of physicists. Not. Dunning-Kruger effect in full force.
I don't know about you, but that link goes to an article that has been very cleanly written, no information overload, very well planned. I was surprised that people can write scientific stuffs using such clarity.
The interesting thing is that Couder's experiments with silicon walkers that replicate on a macroscopic scale the two-slit experiment require an "ether" substrate
Or just a permeating wave function of the object being diffracted... There are plenty of analogs to the wave equations in quantum mechanics in various fluid media, but that doesn't mean quantum mechanics implies the existence of a fluid ether.
By explaining that those extra supersymmetrical particles are actually packed away in really tiny dimensions that the LHC can't touch. Prove it aint so!
When the TOE is cracked we'll be able to hunt down all resources on this planet and know how turn them into useless trinkets and garbage.
the Higgs Boson is one of the century's biggest discoveries.
Whilst this discovery is great, I really hope that you're wrong! Roughly 100 years ago Rutherford discovered the nucleus (1911 according to WIkipedia); but in the same century we subsequently discovered the protons and neutrons which make it up, the pions which moderate their interactions, as well as the quarks they're made of and the gluons which moderate their interactions, along with a bunch of other bosons and mesons. We also discovered General Relativity (Special was already known by 1905) and Quantum Mechanics (including the standard model), black holes, neutrinos, W and Z bosons, muon and tau leptons and anti-particles for the above, as well as inferring the Big Bang, dark matter and dark energy and we gave Thermodynamics an information-theoretic renaissance.
That's just in Physics alone!
A century ago there was no heavier-than-air flight, whilst these days we complain that the food on our £30 flight is crappy. Walking on the moon became so routine that the public lost interest and we stopped bothering! A century ago there was no genetics or germ theory. Computers were people that were good at sums. Experimentalists were attempting to transmit sound via radio waves.
I'm very much looking forward to this century's discoveries :)
Sorry, I have trouble with these big letters, a handful short lines shown at a time, and huge images that take up a lot of the screen. Feels like an oversized mobile site or a powerpoint with vertical scrolling. I'm reading this at a low res desktop not on a 2048x1536 tablet. Thanks.
Perhaps it's time to reexamine Coleman-Mandula and see if there are some conditions that can be relaxed and thus create a variation of supersymmetry.
I was really interested in reading the linked article, but the author completely ruined the experience for me by quoting Ernesto Lynch. Why would a scientist use his public forum to promote such a guy? I suppose it's considered okay in most academic circles.
They quote Che Guevara, who in some countries is still thought of quite warmly (incl. much of Europe). Ernesto Lynch was his father's name, not his. And why it was ruined by a quote by a guy that's been dead for 45 years, no matter how you feel about his life, is beyond me... you were one of the people trying to capture him?
All the stuff you listed happened in the first 60 or so of those 100 years. Nothing much has happened since then.
You meant Ernesto Guevara, surely. Ernesto Guevara Lynch was his father - and, in any case, Lynch was a second surname.
https://www.youtube.com/watch?...
The Higgs Boson was supposed to have an Earth-shattering Kaboom.
They found something that they called a Higgs Boson, but what they found doesn't have the earth-shattering kaboom the Mathematical Physicists predicted it would.
Where's the kaboom?!?
this makes me happy, and the researchers should be happy as well...so another theory is proven wrong...*that's science*
Thank you Dave Raggett
All the stuff you listed happened in the first 60 or so of those 100 years. Nothing much has happened since then.
...he types into a handheld device capable of performing billions of operations per second and accessing the sum total of the world's knowledge, before sending that message via invisible waves to one of the thousands of machines we've put into space, which then beams said message all over the world so that everyone has the opportunity to testify to rich_hudds's breathtaking shortsightedness.
Could you be any more pedantic?
OP said:
"the Higgs Boson is one of the century's biggest discoveries"
All the stuff you listed happened in the first 60 or so of those 100 years. Nothing much has happened since then.
Except the internet, cell phones, massive advances in solid state physics and chemistry (e.g. battery capacity), we've left the solar system, landed on Titan, discovered a hexagonal vortex on Saturn, found more and more drugs, harnessed solar and wind power, and...
This new 'it's' is a new black or something.
"it might be time to start hammering in those coffin nails."
Quite clearly you are a SUSY denier. Have you not seen the models? The many papers? To deny the existence of SUSY is to deny all but certain fact! And do not resort to quoting LHC "results" as that is just chery picking from the very large parameter space SUSY occupies!
ummmm.... really?
On a point of pedantry, there was powered heavier than air flight over 100 years ago (the Wrights flew 110 years ago).
Oolite: Elite-like game. For Mac, Linux and Windows
There are many "we"s in the world of Physics.
Some of the quieter groups may get more publication traction now that the LHC is failing to support their more widely accepted peers.
Previous posts were talking about fundamental particle physics then you jump to examples from electrical and material engineering...
I'm looking forward to the next unexpected plot twist.
Thermonuclear weapons were a big one, and I'd say that low cost global communication (the worldy widey web) was the next.
A lot of the rest has just been grinding on existing technology. Metalworking progressed from steam engine boilers in the 1800s to jet turbines in the 1950s, and that supported the engines that have driven the ongoing transportation revolution. Moore's law-like progress has ground away at computing, from punch cards through transistors and micro- now nano-chips.
I hope the next "big one" is free energy.
Since 1974: charm, bottom and top quarks, gluons, tau lepton, tau neutrino, W and Z bosons, Higgs boson. We talk about the Standard Model as if it's been around forever, and bemoan the lack of "new physics," but half of the model was discovered in the last 40 years.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
Previous posters might have been a bit off for their cutoff, but of the long list you give, all but the top, tau neutrino and Higgs were discovered within 5 years of your cutoff. The top quark and tau neutrino were where theoretical particle physics started seriously outpacing experimental physics. Some great work is still being done, but a lot of it comes down to increasing precision of previous work and ruling out a small subset of theoretical extensions to the Standard Model. This does amount to a tappering off of game changing discoveries and the threat we might be orders of magnitude in experimental performance short of new ones at some point.
As they say, the sound of science is less 'Eureka!' and more 'That's strange...'
I hope the next "big one" is free energy.
This places you in the category of people who do not understand thermodynamics. There is no such thing as free energy, nor will there ever be. Furthermore, extrapolating from current energy usage increases, we only have a couple centuries before the amount of heat we generate (and keep in mind all generated energy ends up as heat) becomes as serious a problem as CO2-induced forcing. We do not want or need to boil our oceans by sucking on the teat of some miraculous new energy source.
"But but but future tech!" No. Thermodynamics is real. Proven. And among other things it says that we can't radiate heat to space (or anywhere else) very effectively.
"But but but future tech!" No. Go jerk off to Star Trek or something. Over-unity is the pipe dream of the scientifically illeterate.
Duh...'cause it's too hard to type & say?
We've nailed down the age of the universe; discovered inflation, gravitational anomalies (AKA "Dark Matter"), and black holes; harnessed the spin of the atom; created Bose-Einstein condensate; mapped the microwave background; discovered gravitational lenses ('79), super-massive black holes at the center of galaxies, and with them the cause of galactic jets and quasars. We've discovered material with a negative refractive index and with a refractive index less than one.
Actually the Michelson-Morley (Morley-Miller actually) experiment is interesting because the results showed there to be some form of ether. The amount of the drift was different than what was expected. It wasn't until many years after Miller's death that Shankland took the very extensive amount of data that Miller had accrued from the many-many reading and threw most of it out completely and found one small set of a dozen readings or so that he could claim were wrong. Now everyone is taught that the results showed no ether the whole time when it was really a fraudulent scientist trying to help out Einstein's theories that changed the results of that experiment.
-- ssoorrrryy,, dduupplleexx sswwiittcchh oonn.. -Quote found on actual fortune cookie.
I hope the next one is free entropy.
Problem solved!
I hope the next "big one" is free energy.
We got "free energy" in the 1960s. Unfortunately the power companies found a way to charge us for it.
And again, listing things that are in other fields, not fundamental particle physics. Might as well take the straw man a step further and just talk about the guy who said all inventions have been invented. It would be idiotic to claim all progress in every field has stopped... but that isn't the issue, the issue is that fundamental particle physics has leveled-off somewhat, reached a slower point (not stopped..). The astrophysics work I do overlaps enough I can list new things being discussed about in the just the last week, but the still pale in comparison to some of the really significant things found decades ago.
"Free energy" is my shorthand for clean, practical fusion. We've already got it in the sun, but being able to harness that power on Earth and turn it to electricity, that's what I'm calling "free."
Given practical fusion power, you can construct sun shields, really big ones.
You can also pump heat into the planet's core, which might be a very beneficial thing, long term. I'm not talking about just keeping the core liquid and flowing to perpetuate the magnetic field, I'm also talking about sucking the heat out of places that you want to make cooler to get the heat to pump into the core. Too expensive, you say? When energy costs less than 1% of what it does today, per kWh of useful electricity, it's pretty amazing what doesn't cost too much to do anymore, starting with refining metals like Titanium.
I like Fission power, I think we should have more of it, but I acknowledge there are legitimate concerns.
Politically, I think we're being really idiotic about it - limping along the old, relatively unsafe reactors until they are even more unsafe than when they were constructed instead of building new, better ones and decommissioning the old ones. Also, Germany shutting off their nuke plants so quickly as to spike the coal mining industry - that's really bright.
Back then very little of those enterprises were regulated, prohibited, and beaurocratized by law.
People could just do things without being afraid of the government. These days we can't even discover new breeds of corn without the FDA (i.e. the luddites) proclaiming that nature is being messed with (meanwhile real human beings are starving to death, but that's OK because it will solve the imaginary problem of overpopulation).
Back in the day transmutation was a big discovery that is now fully illegal under all circumstances. Can you imagine what would happen if the government found out about someone doing something like what Marie Curie was doing in their basement? It's hard to think about any advancements in flight when home-brewed drone hobbyists are attacked by the FAA.
Innovation happens when people can reap the rewards of their work and society allows them to prosper and take risks without confiscating their property under claims that everyone is taking a risk and so no one should.
Back in the day transmutation was a big discovery that is now fully illegal under all circumstances.
Um, no it isn't. It's extremely dangerous without the proper equipment, of course. And I'm pretty sure possession of weapons-grade uranium or plutonium is illegal, but there are other good reasons for that.
Can you imagine what would happen if the government found out about someone doing something like what Marie Curie was doing in their basement?
As a matter of fact, something like this really happened, and he was ultimately shut down by the EPA, but I don't think he ever faced criminal charges. The reason why the government clamps down on such experiments is that it's incredibly dangerous and runs a significant risk of killing innocent bystanders if proper safety precautions weren't taken (which they certainly weren't in this case). If someone kills himself in a crazy experiment I don't think it's any of my business, but the freedom to experiment and innovate should not include the freedom to recklessly endanger others. Protecting us from deadly lunatics is one of the basic functions of government, not some mad authoritarian scheme.
So how did the guy in his basement (who sounds from your description to be OK) endanger society?
Transmutation to weapons grade uranium is a big jump: as in 10's of billions of dollars and 5 - 10 years of industrial activity (e.g. the Manhattan project).
So how did the guy in his basement (who sounds from your description to be OK) endanger society?
Jeez, try reading the link:
"Although his homemade reactor never came anywhere near reaching critical mass, it ended up emitting dangerous levels of radioactivity, likely well over 1,000 times normal background radiation."
"EPA scientists believe that Hahn likely exceeded the lifetime dosage for thorium exposure"
Would you want to live next door to that? I certainly wouldn't, and I'd be perfectly happy living downwind of a well-run and inspected nuclear power station. And I've been working around sources of radioactivity for the last ten years - the difference being the use of well-established containment procedures and professional handling.
String theory is a mathematical model that attempts to unite all of physics. String theory has many attractive features that make it SEEM promising as a way to reconcile relativity with quantum mechanics - it's not at all surprising that, at least at first, it generated great excitement among researchers. Yet one of the key criticisms of string theory is that for all the effort spent trying to prove it, it has made virtually no testable predictions - leading to the suggestion in some circles that it isn't even quite a science. For string theory to be a viable description of reality, it requires supersymmetry to be true. Supersymmetry predicts that there are a whole slew of as-yet-undetected subatomic particles with certain well-defined characteristics. Each time the LHC ramps up to a higher energy level, string theorists get their hopes up that some of these particles will be found. So far, nada. If supersymmetry can be decisively DIS-proven, it may mean that string theory must be abandoned. This is a much bigger deal than you might think. The amount of time and effort spent trying to advance string theory has been staggering. String theory has dominated theoretical physics for decades. Anyone wishing to find gainful employment in theoretical physics any time in the last several decades has basically had no choice but to embrace string theory and slave away at the horrendous mathematical challenges it presents. There has been virtually no interest in - or funding for - research into other approaches to uniting physics since the 90s at least. Anyone who seriously advances a non-string based unified theory is openly mocked and derided; string theory has become a virtual cult in the world of theoretical physics, to the detriment of any other theory. For string theory to be exposed as ultimately worthless would be a seismic shock to the scientific community; generations of physicists will have spent their entire careers crawling determinedly down a rabbit hole that leads nowhere. It'll be as if they'd spent their time researching the biology of dragons or unicorns.