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Higgs Data Offers Joy and Pain For Particle Physicists
scibri writes "So now that we've pretty much found the Higgs Boson, what's next? Well: 'There's going to be a huge massacre of theoretical ideas in the next couple of years,' predicts Joe Lykken, a theoretical physicist at Fermilab. The data has shored up the standard model, but technicolor is dead and supersymmetry is starting to look pretty ropey now. Theorists are now poking at the mathematical chinks in the standard theory in the hopes of being the first to find a deeper truth about how the Universe works."
Theorists are now poking at the mathematical chinks
I realize Asians are known for excelling at math, but do we really have to bring race into this?
I'm very, very sorry. I couldn't resist. I understand I'm a terrible person, you don't need to reply and tell me that.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
It is not confirmed, but it is not expected to not be confirmed, so nothing lost by starting on the theoretical work ahead of the confirmations. In the unlikely case it turns out to be something else, we can just start over.
Did you miss the part about "looking ropey"? That's String Theory on Steroids.
Sheesh, evil *and* a jerk. -- Jade
I predict, over the next two years, what's going to come out of this is the following:
Physicists will have poked holes in most all the prevailing Standard Model-compatible theories, and will start talking about the inadequacies of the LHC and how we need a much bigger collider to prove or disprove the existence of those elusive super-partner particles required by supersymmetry.
#DeleteChrome
It's unknown but really likely. There is definitely a particle at around 125 GeV but there certainly is a (very small) chance it could be something else.
The standard model predicts a number of different ways the Higgs Boson can decay and what probability it has for each type of decay.
The most common easy to measure decay modes are:
Higgs -> Two Photons (high energy gamma rays)
Higgs -> Two W Bosons -> 4 leptons (electrons or muons)
So what they are actually seeing is the decay products and they measure the energy of each component of the decay and add that up to find the original energy of the Higgs.
The measurement of the two photons is called the "gamma-gamma" channel or "diphoton" channel. They call the 4 lepton channel the "golden channel" because it's a pretty clean signal with a low "background" (noise). That is, they get a good signal to noise ratio from the 4 lepton channel.
The theory says that the two photons should happen a certain % of the time and the 4 leptons should happen a different % and the other decay modes should happen with other probabilities.
One of the reasons to believe they have found the Higgs boson and not some other particle is that the decay relative rates for each type of decay are pretty close to what the theory suggests.
The best way to study the Higgs would be to produce lots of them accurately without producing other particles. The best-known way to do that is with a linear collider that smashes leptons (usually electrons) together. They can tune the energy of the collisions to the exact value to produce Higgs. This is how the W boson was studied so accurately at SLAC. A new international linear collider (ILC) would need to be built to reach the energy levels needed to make the Higgs. Luckily, it's a pretty low and easy to reach energy compared to what it could have been which makes an ILC somewhat reasonable to build.
From what I understand it was only one single experiment that showed us something that we think is where/what the Higgs Boson would look like.
Has it been reproduced or confirmed?
That's not very definitive. Can anybody else around well versed in particle physics tell us if the Higgs has really been found or not?
I think that the announcement is based on a couple of years of data collected by two different teams using different methods, so calling it a single experiment seems a bit of an over simplification. See Higgs Discovery: The Data blog entry by Matt Strassler.
Some privacy policy Slashdot.
Every new discovery of the past few decades has supposedly "killed" SUSY, but every time it makes a comeback with a modification to avert whatever problem the observation caused. Other theories do the same, to a slightly lesser extent.
I don't see why Technicolor is dead. The Nature article makes the claim that it's because Technicolor is Higgsless, but that's something of a falsehood. Technicolor lacks an elementary Higgs, because the role played by the elementary Higgs in the Standard Model is instead played by a composite particle. As far as I can tell it's perfectly possible that the bosonic state at 125GeV is a composite rather than elementary Higgs.
(FD: I'm a PhD student with a thesis area based around technicolor)
This is an idiotic analogy. This isn't about breaking things, it's about reproducing the kinds of conditions necessary to observe phenomena. Do you feel the same way about dissecting animals to learn about internal structure or heating various substances to get spectral signatures.
If you're going to confirm or throw out a model of subatomic physics you're going to have to use accelerators to produce the conditions where particles can be observed.
The world's burning. Moped Jesus spotted on I50. Details at 11.
Uh, I hope you realize that Dark Matter doesn't have anything to do with the universe being "dark". Besides, it's not dark in the microwave band anyway. The Dark Matter "bandwagon" is trying to account for 23% of the mass of the universe which does not interact with the electromagnetic field, and hence is "dark". Much of this is hot dark matter consisting of neutrinos (generated by the conversion of a proton into a neutron) and antineutrinos (generated by the conversion of a neutron into a proton). These reactions were known in the Twentieth Century. Neutrinos have a very low rest mass, and travel at just under the speed of light. So infrequent are their interactions with normal matter that a neutrino would be able to pass through a light-year of lead with no scattering events. That leaves warm dark matter (with velocities from 1 to 10% of c) and cold dark matter (with velocities below 1% of c) to be discovered. The negatinos and positinos of supersymmetry theory were promising in this direction, but apparently have been falsified. But no one is "afraid".
The LHC was built to find any new physics, not just the Higgs. The fact that we've been able to rule out SUSY for large mass ranges is part of that. To measure the specific properties of one particle though does need something a bit more purpose-built. They'll be able to measure a lot about the Higgs boson but not anywhere near as much as a linear collider could measure.
Also, for part of the year they stop injecting protons and instead inject lead nucului. This is meant to measure extremely messy but very high energy collisions that should generate quark-gluon plasmas.
Discrediting a theory isn't a permanent thing. Any theory can be brought back if evidence warrants it. Even Einstein's "biggest blunder," the cosmological constant, is now the most popular theory to explain the universe's accelerating expansion.
One of the reasons to believe they have found the Higgs boson and not some other particle is that the decay relative rates for each type of decay are pretty close to what the theory suggests.
Actually that is not really true because we do not have enough statistics to measure these rates with any accuracy. In fact the "most likely" value for diphoton rates for both ATLAS and CMS are quite a bit higher than the Standard Model predicts but the accuracy is sufficiently low that they are not yet inconsistent with the SM values. So really the rate measurements are currently far too inaccurate to have any idea whether this is a Higgs boson or not but things are improving rapidly as we gain statistics.
What is far more important at the moment are the decay channel observations. Since it decays into photons, W and Z bosons we know it must be either a spin-0 or spin-2 particle and it cannot be a fermion (spin-0.5). The Higgs should be spin-0 so this is consistent but not conclusive. Essentially it decays into the particles it should do and it _potentially_ has the correct spin. We can get a more accurate determination of the spin i.e. whether it is spin-0 or spin-2 by looking at the angle between the two leptons (electron or muon) produced in the WW decay channel - expect results from ATLAS and CMS on this soon.
However by the end of the year the rate measurements should be a lot more accurate and things will possibly start to get interesting if the current diphoton rates stay where they are but we end up with less uncertainty on the measurement.
This is worth a watch...
http://vimeo.com/41038445
Enjoy!
Name: Mr. Anon E Mouse; SSN: 555-55-5555
> There are no experiments you can perform to confirm or invalidate the existence of God.
Actually there is. Unfortunately it requires death as that results of that experience and the aftermath will provide all the proofs and more then one person could ever dream that indeed your consciousness simply changes state after death, and that there is a super-consciousness to the sub-consciousness of everyone. *Unfortunately* getting the results of said experiment back to the living is the catch. The other "kink" is that: Besides if you already knew the answer, it would (mostly) invalidate the purpose of being human in the first place.
The other way would be to learn meditation and learn how to interact with your True Self. Again, unfortunately one could spend an entire lifetime before ones "get confirmation" that there is indeed far, far more to "who you truely are."
The point though, either way the answer is largely irrelevant in the grand scheme of things. There are indeed many good people of all kinds of beliefs, faiths, and lack of said beliefs and faiths. If one has to rely on an external force / rules to be positive internally methinks one is the missing the *whole* point of religion which is little more then spiritual kindergarten. At some point one doesn't need others telling you to internalize how to treat others with respect, kindness, etc.
The ignorance and arrogance of man is to simply assume that some questions are unknowable. They may not be easy to get, but they are indeed there if one dedicates their life to seeking them. Again, the proof of this, sadly, is also going thru the death experience.
It is simpler to "just get on with life" - learning and loving. That's what its all about at the end of the day -- creating positive relationships with everyone else.
The instant someone is trying to "sell you" a philosophy is the instant it would be good to be skeptical of their agenda.
"Joy and pain"? Jesus, what are they doing, tying the boson in a knot and putting it up their bums? (I guess it would have to be a "boson's knot").
Instead of the God Particle, they could call the "Oh God! Particle".
[note: I only make this kind of off-color joke because it's past 9pm and the children have all gone to bed. I call this the "safe harbor" hours, when normal FCC rules moderating online behavior are relaxed, like a sphincter with a Higgs Boson in it. Thanks to these safe harbor rules, constitutionally-protected free speech rights of adults are balanced with the need to protect children from harmful content, like the word "fuck" and references to tying massive particles in knots and putting them up one's bum and then pulling it out slowly as climax is achieved (thus the expression "string theory"). Two physicist doing this while standing face to face are called a "Hardon Collider", named for the famous Scottish physicist Sir Ivan Hardon (1847-1903) who first posited that there's nothing else to do while waiting for the experiment to finish and there were so few female physicists back then that, hey, what happens in the lab stays in the lab. Tragically one of his experiments exploded while Hardon and a lab assistant were engaged in this act of outrage and since they had their pants down both of them got kilt.]
You are welcome on my lawn.
String theory has many, many variations. Falsifying them means first narrowing down which variations just might have some correspondance to physical reality, then finding ways to test those further. All the ones that we could call interesting (because they might fit 'objective reality for this universe'). involve very high energies, so we can't build an accelerator nearly powerful to test them by that particular method. That's not the same as being untestable - for example, a particular string model might make predictions about something else, like Proton decay, that we can test. Some versions imply things about cosmolgy that we can test by astronomical observation.
The point is, that we probably won't test all the variants much or at all. Sometimes, a physicist may decide to toss out a bunch of variants because the equations look needlessly complex or full of fudge factors - scientists often look for certain types of style or form in fundamental equations, as when Einstein decided to not add the complexity of a Cosmological constant to General Relativity. It's not the same as doing a scientific test for falsifiability to just decide not to look at the more complex equations at all and hope you will either find something going through the more beautiful and elegant versions, or shoot them all down, and then some grad student can try some of the more complicated variants.
It is essential to science that experimental results are public and repeatable. What you are talking about doesn't fit into those categories. Perhaps you could call it knowledge, but it isn't knowledge in the ordinary sense.
If I had a dream where I met Satan and he told me his favorite shampoo, you could call that knowledge, but it isn't knowledge in the scientific sense, or even common sense.
The three valence quarks inside a proton for instance have a rest mass of only 11 MeV/c^2, which they get by means of the Higgs mechanism. The rest of the 938 MeV/c^2 that is the full rest mass of the proton is its quantum chromodynamic binding energy, that is the energies of the gluons that are keeping the three quarks together, so the Higgs mechanism accounts for only 1% of the mass of a composite particle like a proton. Not all mass is drag in the Higgs field. It is by no means the final word on the origin of all mass. If the Higgs mechanism was the only way particles could acquire their masses, then the neutrino should have zero mass, and well, it doesn't.
Qu'on me donne six lignes écrites de la main du plus honnête homme, j'y trouverai de quoi le faire pendre.
The "v" in the context of W decay to "lv" is a neutrino ("v" is a close approximation to the lowercase N or Nu in greek ν)
only one single experiment
Actually, it was two different experiments: CMS and ATLAS. The LHC is the big ring-like structure that accelerates particles around it; CMS and ATLAS are two detectors at different points on that ring that watch as the particles collide with each other. Both CMS and ATLAS have detected a new particle, with the same mass (~125 GeV), with about the same significance (~5-sigma, or about a 1-in-50-million chance of getting that result by chance).
The mass is about what the standard model of particle physics predicts for the Higgs boson, so it looks very much like this new particle is it. But the physicists are being careful not to state outright that they've found it, because there are certain properties that the Higgs is expected to have - charge, spin and parity, I think - which they haven't been able to measure yet. When they've got enough data to measure those, and if they match what the Higgs is supposed to have, then they'll state that they've definitely detected it.
While disproving the existence of God is effectively impossible - proving it does exist would actually quite simple, provided you had His/Her/Its/Their cooperation. The fact that their is no credible evidence the existence of God suggests that either:
1) It doesn't exist
2) It doesn't desire to prove Its existence, or
3) It's incapable of proving Its existence
Considering we're talking about a being who most claim created the universe and intervenes in peoples life in ways both subtle and miraculous, number (3) seems unlikely - even just having one of his chosen messengers take part in a double-blind psionics test while God read out the cards to them would be enough to give the question serious scientific merit.
Now (2) could very easily be the case, and is in fact perfectly consistent with some faiths. But in that case I would suggest that either It doesn't actually care about our worship, codes of conduct, or the other stuff religions tend to obsess over, or It's a complete jerk: "Yeah, I know it's been a hundred generations or so since I bothered to offer any evidence that I even exist, much less which of the hundreds of continuously-mutating religions I endorse, but you didn't follow the right one so you're getting eternally condemned anyway".
Which leaves (1) as the default assumption. Either God doesn't exist, or It wishes us to be free to conduct our lives as though it does not - in which case spreading the "Good Word", especially through coercion, would seem to run counter to God's will.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
"Experiment" in this context refers to each of the six installations on the ring: ALICE, ATLAS, CMS LHCb, LHCf, and TOTEM. So that's 18 PB/y in total.
Stupid universities wasting time and money trying to advance human knowledge. They could use that money to.............. Buy a tomahawk missile?
If you think someone isn't free to have a different definition of "freedom" you may be a tyrant.
the cosmological constant, is now the most popular theory to explain the universe's accelerating expansion
describe, not explain
Something bad is coming when people are suddenly anxious to tell the truth.