Hints of an unexpected new particle could be confirmed within days
blogs.scientificamerican.com
blogs.scientificamerican.com
Since then there was an update in march where ATLAS still sees a global significance of 2 sigma and CMS is down below 1. Local significances are up though CMS has pushed their 2.6 to 2.8, and ATLAS has gotten their 3.6 sigma into 3.9 (Both have also added a new model for interpreting this, I'm just giving the largest sigma values reported). The reason improvement is so modest is because there hasn't been any new data on account of the LHC being set in the "off" position.
Anyway, the reason the OP article is such crap is that it doesn't mention any details about the rumour it is so clearly based on. Perusing more technical rumourmongers I find a mention of a 4.7 sigma excess in an ATLAS analysis that wasn't approved in time for the big conference in March. So if the article is based on that rumour, it is about three months old by now. But we can't tell, since the author wusses out on even saying what detector will "CRACK PARTICLE PHYSICS WIDE OPEN"... -_-
(And thanks for the great summary.)
However, CMS saw something like a spin-2 particle, but with less certainty, so their claim can be just a wishful thinking if ATLAS comes close to the 5 sigma?
Disclaimer: not a particle physicist, just based on another articles I read. If somebody knows more she (or he) is more than welcome to correct.
"This could mean nothing less than the fall of the Standard Model of particle physics (SM)"
No, it means that the SM is an approximation to a deeper theory, which everybody already believes anyway and has for several decades. Models don't "fall" just because they turn out to be approximations.
"The SM describes what the building blocks of the universe are and how they work, and from there, at least in principle, explains every other phenomenon in nature."
No, it doesn't. The SM doesn't include gravity. It also has twenty-six free parameters that have to be determined from experiments; it doesn't explain why those parameters take the values they do. So it's obviously incomplete, and everybody has known that for several decades.
(Yes, the article does go on to talk about the SM being incomplete. But that just means it contradicts itself.)
In short: the article talks like this discovery is somehow a huge change in how everybody views the SM. In fact it's business as usual: we built experiments to try to discover new physics to help us extend a model we knew was incomplete, and now those experiments are bearing fruit. This is normal science. It is not some huge rift in particle physics.
and
>The SM doesn't include gravity. It also has twenty-six free parameters that have to be determined from experiments; it doesn't explain why those parameters take the values they do.
26 free parameters. Yikes.
At what point does the addition of parameters and particles break through from "yet another particle we expected" to "this is completely unexpected and we need to seriously modify our understanding". Obviously with geocentric vs heliocentric it took a major shift in understanding before epicycles crumbled. Same with newton to einstein -- a major shift in understanding before minor errors were explained.
Aside from the SA hyperbole, do you think there is any evidence that particle physics is reaching critical mass in terms of convoluted explanations?
Of course, it could be the case that nature is just damn complex at the particle level.
I don't think a shift like this is precipitated by exceeding some limit on free parameters. It's precipitated by a new discovery not fitting with current models. When the Higgs was discovered, it was just a confirmation of what the SM already predicted; it filled in another free parameter in the SM (the Higgs mass, which had only been roughly estimated before), but it didn't point the way to any new, more fundamental model. This new evidence, if it pans out, does point the way to some new, hopefully more fundamental model, because it's something that isn't included in our current models. That is true even if it has no effect at all on the number of free parameters in our theories.
(Btw, the 26 free parameters in the SM sounds like a lot, but since it includes all of the fundamental interactions except gravity, those 26 are really just a collection of all the free parameters from previous theories of those same interactions. For example, the mass and charge of the electron were already free parameters in electrodynamics, so the SM didn't add them on out of nowhere.)
Also, as I've commented already, the SM has been understood to be incomplete for several decades. Everybody already expects that there will have to be a significant shift in our understanding when we go to the next level down. We just don't know what that shift will be, because up to now we've had no experimental data on the question. Now we might finally be getting some.
I agree that the number of parameters needed is less than the number of experimental measurements though, I confused that.
This is true, in practice we can't do all of the derivations from first principles. But AFAIK this is an issue of, as you say, computational power; it is not an issue of theoretical insufficiency (at least within the domain that the SM covers, i.e., the non-gravitational interactions in flat spacetime with gravity being negligible). We know what equations we would have to solve; we just can't solve them analytically and we don't have the computing power to solve them numerically in all cases.
"Originally theorists thought that the SM would be an approximation of a more fundamental theory that would be quickly discovered. This is what has always happened in the past."
No, what has always happened in the past is that it's taken a long time for the next more fundamental theory to arise. The article gives Newton's theory of gravity as an example. Newton published the Principia in 1687 (and discovered the key elements of the theory a couple of decades before that). Einstein published General Relativity in 1915. That's not a "quick" discovery of the next more fundamental theory.
As another example, Maxwell's Equations were published in the early 1860s. Quantum electrodynamics, the next more fundamental theory, was published in the late 1940s. Also not a "quick" discovery.
Can SM not represent integers?
No. The point of physical models is not to be able to answer all possible questions that you can ask about the models, that as you point out, is not possible.
However, the point of a physical model is to simulate reality. This does not entail being able to answer arbitrary questions (in finite time) about it.
Consider building something like a Nintendo Emulator. As a first pass, you might simply say "I just need to specify the registers and assembly instructions." You might miss out some assembly instructions, and when you pass in a program that uses them, your emulator would crash. You then add that in, and might find out that in order to do faithful reproduction, you need to model instruction execution time and so forth.
In short, your building an emulator requires you to figure out
1) What the state of the Nintendo system needs to be (this may include a time variable).
2) How to correctly handle state transitions.
However, even after you get a complete model of the Nintendo, this obviously doesn't let you answer questions like "If I were to pass in an arbitrary program to my emulator, would it halt on arbitrary inputs?"
Physics is the same. We want to figure out how to specify the "state" of the system, and how that state evolves with time. When we say that a model is incomplete, it means that we're missing some assembler instructions, a register, or something else that doesn't allow us to faithfully simulate reality.
Discovering a new particle is like discovering that there are a bunch of new registers and associated instructions that we need to account for.
The person I responded to said that SM was incomplete, but that must be the case, unless the model is self-contradictory (assuming it's not, as it would not qualify as a scientific theory if it were), or, the model must not have enough arithmetical complexity to fall under Gödel's rubric.
This, for the first time in a long time, would put experimentalists ahead of theorists. That could easily 'crack wide open' a new set of theories to explain the possible particle. Hardly click-bait here, IMO - the content is sufficiently exciting relative to the headline.
"Crack Wide Open" implies, to me, that this discovery somehow shows that particle physics is on a wrong track and needs to drastically change course. (In other comments I've pointed out statements in the article itself that give the same impression.) That's not the case at all. Particle physics has been stalled because of the lack of new experimental data to help theorists extend their models. This discovery, if it pans out, will help particle physics to start up again, exactly as particle physicists have wanted to do for quite some time.
In isolation, it might not. Taken by itself the phrase is open to multiple interpretations. But in the context of the article as a whole, I think it does.
I also think it's generally bad for discussion to do what you are doing, which is to latch on to a very specific interpretation of a single phrase, and pushing to get everyone else accept that interpretation, instead of taking other comments as additional information about how the words can be interpreted and allowing for those different interpretations to coexist.
You've never heard this phrase in the context of, say, a fictional detective talking about an unsolved murder? "I'm about to crack this case wide open!"
Sounds to me like you just never quite understood what people meant by Crack Wide Open. It doesn't mean the theory is going to crack under pressure, forcing us to completely abandon it. It means deeper science, previously stuck inside a 'tough nut to crack', is finally going to be revealed.
EDIT: wow, looks like somebody else had the same exact comment to make. At least it corroborates the point..
The issue to me with clickbait headlines in general is that they have zero information content. Think about how a decent scientific paper is structured - the title gives the broadest possible overview of the content, then the abstract gives a summary of the content, then the paper itself gives the details.
To me, the ridiculously overstated nature of most clickbait headlines is the lesser problem.
This is not the first known violation of the standard theory. The standard theory did not predict neutrino mass, and did not predict neutrino oscillation.
No, just that it's not the kind of event the article is trying to portray it as.
> it seems to me that experimental evidence of a new, hitherto unforseen particle is about as disruptive of an event one can expect in particle physics, no?
No, it's not disruptive. What has been disruptive has been the several decades without any new experimental results that could help particle physicists to extend their models. Now we might finally be back to the way science is supposed to be done: building theoretical models using experimental data as a guide. This is what particle physicists have been hoping for; it's not a disruption at all.
Not if the sudden change is exactly the one that everyone in the field has been working for and hoping for.
What?! That statement is absurd - reminds me the story of how geocentric model was "adjusted" when new measurements came along. That just leads to overfitting a model. The property of a sound theory is that it can predict future data; it does not just rationalize on data already acquired.
My phrasing evidently did not make my point clear. The SM has been known to be an approximation (the usual term is "effective field theory") for several decades; and furthermore, there are well-understood reasons why that particular model is a good approximation up to a certain point. None of that changes if and when we discover experimental evidence of new particles not included in the SM (as we might now have done); in particular, the structure of the SM itself will not change. What changes is that now we have (hopefully) some evidence to help us build the theory at the next level down, the theory to which the SM is an approximation.
That process will not consist of adding parameters to the existing SM (which would be "overfitting"). It will consist of building a new model and then showing how the current SM arises as an approximation in the new model. If we had had this evidence several decades ago, what we now call the "Standard Model" would be that new model instead of the one we currently call the "Standard Model"; we could have jumped to the next level then instead of having to wait.
This is so wrong. Finding the Higgs where it was expected was very important because otherwise "what was already known" would have been false.
This, I think, is exactly the kind of discovery that people expected from the LHC: Something new and exciting that invalidates our current theories and gives us a possibility to devise / test new ones against real experimental data. After all, the real shortage in particle physics is not the number of theories (we can invent a quasi infinite number of them), but the data against which we can test them.
Now since the last chance of "new physics" due to the lack of a signal where a signal should have been is gone, everybody turns their hope to finding a signal where no signal was expected. This is of course totally legitimated, but it doesn't take away any of the importance of the former.
I would love to see something new too, but if the SM explains everything we are able to measure today just fine, then be it. Then the SM is all we need, until we are able to measure more. It's just like the people in the 19th century: they had to go with Newton because they couldn't measure anything beyond Newton. But on the other hand, back then Newton was all they needed, because Newton could explain everything they saw.
As far as I know in 19th century there were already the measurements and the calculations resulting from them that didn't match Newton's model.
https://en.wikipedia.org/wiki/Urbain_Le_Verrier#Precession_o...
By the way, Le Verrier also discovered Neptune just by studying the measured movements of the known planets.
Is this suggested particle something like the muon-equivalent of the Higgs?
(edit: I've found http://resonaances.blogspot.com/2015/12/a-new-boson-at-750-g..., which at least has more details and more speculations)
The Standard Model is pretty much believed to be incomplete. It's why many people were hoping to not find the Higgs and allow room for things like super symmetry (SuSy). It is still standing though (which the article mentions), so I'll keep waiting for further experiments on what is going on here
There's speculation this could be as mundane as a penta-quark proton, or a number of exciting particles.
> But this particle is not the Higgs boson: it is six times more massive. Nobody had predicted anything like this.
This is false, there are a lot of alternative expansions of the Standard Model. Each one include a few new particles that are difficult to find because it's necessary to use a bigger (or much bigger) particle accelerator.
For example, the first paragraph of https://en.wikipedia.org/wiki/Higgs_boson#Alternative_models explains a theory that predict a family of 5 Higgs bosons. The lighter one is(would be) the one we had seen. The other 4 are unobserved yet (don't exist because the theory is wrong).
Joking aside, while the article has some content, the headline is definitely tending way to much towards click-bating.
[1] https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headline...
> No.
I have no idea why people insist on quoting an obviously nonsensical formulation of this aphorism. It clearly can only be applied to headlines phrased with yes-no questions, so saying it applies to "any headline that ends in a question mark" is false.
Forgive me if this has been done already.
Even if this does mean new physics it doesn't mean the standard model will 'fall'. It will simply be expanded.
People keep saying this, but it's so obviously false to me I don't understand how a thinking person could believe it.