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LHC Season 2 Is About To Start Testing the Frontiers of Physics
An anonymous reader writes: The final preparations for the second run of the Large Hadron Collider (LHC) are in place. This week, it is expected to start taking new data with collisions at the record-breaking energy of 13 teraelectronvolts (TeV). There are a lot of expectations about this new LHC season. In one of CERN's articles, physicists tell of their hopes for new discoveries during the LHC's second run. "They speak of dark matter,supersymmetry, the Higgs boson, antimatter, current theory in particle physics and its limits as well as new theoretical models that could extend it."
On the other hand, if no new physics is discovered, could this be the Michelson–Morley experiment of the 2000s?
There are no "Frontiers" in Physics. Reality is just what it is, no more, no less. You can't really have 'frontiers' if there is no subject to limit.
However, our knowledge of these laws and of Physics is somewhat limited. So the headline should read: "Testing the frontiers of our knowledge of Physics". But I guess it couldn't fit in a tweet or whatever.
In any case, very exciting times.
If I stuck a weiner in the beam (not mine, one of Oscar Myers'), how long would it take to cook it?
Where is this world eating black hole we've been hearing about? Even The Flash TV show got in on it.
On the other hand, if no new physics is discovered, could this be the Michelson–Morley experiment of the 2000s?
It could be "Shaka, when the walls fell!"
A valid question, and I like a well-turned metaphor ("it was a wine red sea"), but wasn't there a Star Trek episode essentially mocking that sort of usage?
When out president says something is "our Sputnik moment", the Tamarians would understand perfectly.
This could be "The river Temarc in winter!"
Because we're Republicans. We're evil and we hate you. We want to bombard you with heavy particles and see your cellular structure fall apart. We want to create small black holes that will slow time down so you can toil harder and suffer longer before you're spaghettified and torn apart by tidal forces, then evaporate and irradiate you with Hawking radiation so you can slowly die of cancer while your skin sloughs off and your shambling, sore-covered bodies shut down painfully. That is the way of our kind.
I'll wait till it comes out on DVD.
Knowledge is in itself the advancement of man.
Do you also live in fear from the magnatudes more in force and number cosmic rays hitting our atmosphere? Until we can build accelerators that can beat out all such events, I think we are safe.
Letter To Iran
and never will.
Experiments producing and storing antimatter have been going on for decades, e.g. Fermilab's antiproton ring
Wrong headed thinking, those reactions don't have Earth in their center-of-mass as the LHC does. We're DOOOOOOMED, DOOMED I tell you.
8D
Well then. Happy waiting.
They've already made micro black holes. There's nothing wrong with that, they're harmless.
A black hole has no more gravitational attraction then the mass within it before the black hole was there. You'd be more sensible to be waiting for all the metal on earth being suddenly yanked to the LHC's magnets.
Second best episode ever.
I've often thought about this with the rise of the internet meme and think this way of communication was prevalent in the pre written word days, which is why it's ignorant to take stories written down from these times as being literal. Also just as ignorant to dismiss them as such.
On the other hand, if no new physics is discovered, could this be the Michelson–Morley experiment of the 2000s?
That's probably very unlikely. Michelson-Morley was testing a prediction of the best understanding of light at the time. The non-observation of changes due to motion through the ether was clear evidence that the best understood theory for light was wrong.
Now we have found the Higgs the established model, called the Standard Model, has no more predictions to make: we have found it all. The problem is that there are some phenomena which the Standard Model cannot explain, like Dark Matter, and it relies on some amazing fine-tuning of parameters to have such a light Higgs (the odd of this happening by chance are about the same as winning a lottery 5-6 times in a row...and if someone did that nobody would believe it was simple luck!).
The solutions to these issues involve speculation by theorists and there are multiple candidates. Supersymmetry is probably the leading one but if we fail to see SUSY in the coming run then I, and a lot of my colleagues, will probably start to doubt it as the most likely explanation. However even then it might still be that SUSY is the explanation but at a higher energy scale that we can reach and just a more-than-minimal variety of it.
Personally the thing I expect the most for us to find is Dark Matter. this is based on two broad assumptions that cut across many different theoretical models: that Dark Matter interacts through the weak force and that it was thermally produced in the Big Bang. If these assumptions are correct then the mass of the Dark Matter particle has to be in reach of the LHC. However this is still far from any sort of guarantee: there are other models for Dark Matter out there with good motivation which we would not see e.g. axions.
Well assuming it takes a minute in a 650W microwave to cook your disgusting boiled sausage that's roughly 60*650=39kJ of energy, lets call it 40kJ. The LHC beams contain roughly 360MJ. The beams take roughly 90 microseconds to make a complete orbit (27km/3e8 m/s) so that is a power of roughly 4TW (=4 million MW).
;-)
Now the sausage is probably only about half a nuclear interaction length (guess) so only about 18% of the protons will interact per sausage crossing and not all of that energy will actually be converted into heat since much will go to secondaries. So lets be conservative and say that 1% of the incident energy heats the sausage. Hence the the time for the sausage to get 40kJ will be 40e3/(4e12*0.01) = 1 micro second.
Assuming the sausage absorbs 1% of the total beam energy (which will happen in under a millisecond) then it will have about 900 times more energy than it needed to cook it which is the energy released by slightly less than 1kg of TNT...and this is one of the reasons why the LHC is know as the Big Bang machine!
The song of our people.
no freaking idea what it's all about. ... so when talking about what they're doing just say enough to stay credible but lofty-popular enough as not to give people a actual hint (?)
prolly it's not possible to "explain" it to layman because of some treaty with universities else they would lose their income and second prolly because if soemone would go thru the trouble of actually "explaining" it, it might cost them a nobel price or sumething
well nevermind all that ... i was just wondering the other day. ... when "converging" the beams, so basically turn a two way opposite traffic into one lane .. then there are either:
there are two non-continuous beams, bunches as i read and i imagine a round race-car road with "opposite" traffic that is like a race-track full of cars in either direction but the cars are spaced and so is the opposite traffic.
now the question
1) collisions everywhere on the race-track. like everywhere not just in the 4 detectors.
-or-
2) if they can converge them at the 4 special detector points (not at each point of the racetrack) then in reality only two bunches (two cars) from opposite direction have a real collision and the rest of the race cars just crash into the mess left by the first two "cars"?
anyone care to lose their (potential) nobel price and explain?
i think the insurance company would like to know also : )
oh, i hope this research will lead to electrical breakers that break before the for-sure-to-be-broken-over-current current arrives! awesome! super-safe electrical equipment! a breaker that won't turn on because it already knows it will have to break. a smart breaker!
Can you explain why it is found acceptable for the standard model to allow calculation of probabilities greater than one (one of the reasons the Higgs was proposed)?
The Standard Model does not allow for calculation of probabilities greater than one. The Higgs is part of the Standard Model and you only get this effect, called violation of unitarity, for processes like WW scattering if the Higgs is not there. Since the Higgs was found the SM is complete and there is no problem with violating unitarity.
Does the higher energy and luminosity have any real chance of creating dark matter that we didn't see at the lower energy
Nobody can really answer that: we are going beyond the energy frontier and nobody can really say for certain what, if anything, we will find. However if those two broad assumptions I stated above (weakly interacting and thermally produced) are true for Dark Matter then, barring some pathologically strange model for new physics, we should see Dark Matter whether it is from SUSY or something else.
The reason these assumptions put a limit on the mass is that the heavier the particle the earlier the universe will cool to the point that no more can be produced. If this happens really early on i.e. very massive particles, then these particles will be so dense that they will interact and annihilate back into whatever produced them and so there will be very few left, too few to explain Dark Matter. Similarly if they are too low in mass then there will be far more of them because they decouple from the universe later when it is less dense but then the lower mass per particle means that there is still not enough to explain Dark Matter.
For a weakly interacting particle this 'sweet spot' turns out to be within reach of the LHC. This makes no assumption whatsoever about Supersymmetry only that the particle interact with the weak force. However if they only interact through the Higgs then the mass will be higher or (worse) if via gravity then much, much higher. Another possibility is that Dark Matter was not thermally produced in which case you need to know the production mechanism to find out what it says about the mass.
Any SUSY is going to provide a dark matter candidate.
Actually that is not quite correct. A majority do but there are searches conducted at the LHC for something called R-parity violating SUSY. In these models the lightest SUSY particle can decay and SUSY does not explain Dark Matter.
These models are generally less popular because there are very strong limits on them from existing data. In particular these models allow for flavour changing neutral currents and thing like baryon number violation and there are extremely strong limits on both processes not being seen (although we do eventually expect to see baryon number violation).
It will be if it proves that dark matter does not exist.
Plus, Monsanto.
Don't forget to add the thought it may be happening to the DSM-VI.
If it finds no new physics how would that be anything like the Michelson-Morley experiment? M-M proved that the expected aether (that was nearly taken for granted that it existed) that is the background against which one could measure an absolute velocity did not exist (which the Electro-Magnetic Field equations of Maxwell, if properly interpreted, already implied). How would no new physics being found by LHC be anything like that?
Ignoring previous results on the Higgs Boson;
No new physics/results from these collisions would STILL be a welcomed puzzle. It would mean that the expectations are wrong and thus indicate something is missing in the standard model.
Science has progressed equally in the absence of proof as with validation of expectations. It's the discovery and the adaptation of knowledge that is more important.
Nature carries out higher energy collisions in the upper atmosphere (cosmic rays) and has done so for billions of years. No obvious black holes yet - so d'you want to bet? ;)
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
All this machine will do is provide excuses to energize the call for the next, bigger, badder, more obscenely expensive collider. Gimme more power Scotty! When one of these things can fund itself, then I'll be impressed.
E Proelio Veritas.
There's antimatter in your body right now! Your body contains about 175g of Potassium, some of which is the radioactive isotope K-40 which sometimes decays via the release of a positron and a neutrino - positrons are antimatter!
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Actually before the Higgs the problem with the model was that the particles all had non-zero masses. This breaks symmetries which we observe to be held in nature and was a huge problem and also gave rise to the violation of unitarity: if there were no masses there would be no unitarity violations.
Part of the beauty of the Higgs mechanism is that not only did it explain how the particles could have masses while the symmetries of nature we observe are preserved but it also called out the unitarity violations which the non-zero particle masses caused!
Every model has its problems though. The issue with the SM is that the Higgs mass is so much lighter than the Planck scale. This means that there has to be something probably not much higher in mass than the scales we have already probed. However this is not a hard constraint. The higher the energy of this new physics the less "natural" but with only one universe to play with there is no way to be certain that a one in a million chance did not occur when setting up the laws of nature....it's just not very likely.
It's turtles all the way down.
I doubt any revolution in particle physics would ever come from *WITHIN* particle physics.
Really? It has already happened once with something called the November Revolution. This was the discovery of the charm quark which completely revolutionized our understanding of what baryons and mesons were and ushered in the quark model.
Prior to that there was the prediction of anti-matter by Dirac followed by its discovery a few years later which showed that we could unite quantum mechanics and Special Relativity. Prior to that there was Rutherford's discovery of the atom which completely changed our understanding of the nature of matter and all the early work with particles which lead to quantum mechanics. In fact if you look back at the last century or so of physics many of the major paradigm shifts in the field have come from particle physics or its clear precursor.
If you think that getting a PhD merely requires you to accept certain beliefs then you have a very poor understanding about how science works. Good PhD students will challenge the beliefs of those examining them and defend their work using the data and analysis they have in their thesis.
As for damaging careers coming up with some radical new idea will greatly enhance anyone's career...provided that they put in the ground work to do the studies needed to convince others of its worth. Big experiments are an issue because the amount of ground work to get one of these funded is huge and this limits the scope of ideas to ones which are clearly going to work.
Lastly though as for thinking of the Standard Model as the truth absolutely nothing could be more wrong. In fact we usually start by pointing out one of its most obvious flaws: there is no gravity in it! Indeed we particle physicists spend all our time trying to break it by looking for physics beyond what it allows for. Whoever finds physics beyond the Standard Model is likely to end up with a Nobel Prize so I'm not sure why you would think we would not he extremely motivated to break it and why this would not be really good for anyone's career.