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New Particle Identified At LHC
First time accepted submitter m4ktub writes "A team of researchers working with the ATLAS experiment at the LHC have published an article in arXiv where they describe what is believed to be the first observation of a new particle: the boson Chi-b (3P). Professor Roger Jones, Head of the Lancaster ATLAS group, said 'While people are rightly interested in the Higgs boson, which we believe gives particles their mass and may have started to reveal itself, a lot of the mass of everyday objects comes from the strong interaction we are investigating using the Chi-b.'"
They even have chibi particles now.
Give me Classic Slashdot or give me death!
So is that the chibi form of the Higgs boson?
Will His son particle do for now?
Not being an expert in such things, I wonder if anyone could give a good, clear explanation of what they mean by "observed". My understanding is that they are seeing indirect evidence of it somehow? The article (and many that ive seen like this one) seem to stress that theyre not sure, which is why I ask. Is it something along the lines of seeing a burst of EM radiation in a particular signature that they have not seen before, from which they inference a new particle was involved in the collision?
Can someone also explain how they would inference which quarks make up a particle like this? I mean, we obviously cant just place it under a microscope :)
Is it a dot or is it a speck?
The movie about the particle collider this particle's discovery.
/me ducks
"Chi-b Chi-b, BANG BANG"
(Possible) FTL neutrinos, new particle, and the Higgs-Boson on the horizon. It's amazing how many things can get clustered together.
Working...
I bet when you reroute these through the deflector dish, it'll REALLY dry the Borg's shorts!
The second link is hosed, but the abstract says they discovered "a new chi_b state" of quarkonium. This is well beyond my physics comfort zone, and maybe there is no real difference between states and particles in this realm, but intuitively it seems like there should be one. In my, case a hardon is not something I have now, but when I get one, it's not like I get a new organ. It's just a temporary state of a pre-existing organ. Sorry for not using a car analogy; I'm just trying to understand how physicists think of the difference between states and things, or if this dichotomy even makes sense on that level.
CMS and ATLAS are two of a kind: they're looking for whatever new particles they can find.
The new particle is made up of a 'beauty quark' and a 'beauty anti-quark', which are then bound together
Can anyone explain why do they not annihilate?
Quarks come in several different flavours, and protons and neutrons (i.e. almost all "normal" matter) are made of the two lightest flavours: up and down. The heavier flavours are much rarer, and generally very short-lived (which is why you need to "make" them in such an experiment before you can observe them). Quarks normally group up in 3s; with a proton being two ups and a down, and a neutron being two downs and an up. Another form of quark grouping consists of a quark and an anti-quark of the same flavour, which is what's been observed here. And this is the first time that one of these pairs has been observed that consists of quarks with the beauty flavour. Other flavours of pair have been observed before, but its the fact that this one consists of beauty quarks that makes it "new"
sweeeeeeeeeet
Ignore my use of the word "flavour" in the above post ... that's a quantum chronodynamics term, which I managed to confuse with the correct (and much more mundane) term, "type"
Actually this particle is a b anti-b pair(b_bar), and particles consisting of b b_bar have been observed before - what makes this particle different from the others is that the b b_bar are in a different state of excitation (3P) - Just like having hydrogen ( consisting of a proton and an electron) in its ground state (1S) you can have hydrogen in an excited state (2S, 1P, 3S, 2P.. etc..) where the electron is in a higher energy state or orbital. With the strong force a large amount of the mass of most particles is tied up in the field binding the two quarks together, so a quarkonium "atom" in a different excited state can have a vastly different mass than the same "atom" in the ground state. For light quarks (uds) almost all the mass of particles made from these quarks comes from the binding energy of the strong force, a neutron consisting of d u d has a mass of around 1GeV but the mass of each of the light quarks is less than 0.001GeV...(1MeV) - this article really isn't that big news, people routinely find these excitations all the time - the heavy quark excitations are interesting in that the masses of these particles can be predicted relatively easily and can be used to test models of the strong force...
this fits in perfectly in Garrett Lisi's model? http://www.youtube.com/watch?v=y-Gk_Ddhr0M
The second link is hosed, but the abstract says they discovered "a new chi_b state" of quarkonium. This is well beyond my physics comfort zone, and maybe there is no real difference between states and particles in this realm, but intuitively it seems like there should be one.
Combinations of fundamental particles like quarks themselves behave as particles. The most familiar examples of such composite particles are the proton and neutron, but there are many others consisting of various excited quantum states of various combinations of quarks. Quark/antiquark pairs are called "mesons", and combinations of three quarks are called "baryons". Since energy and mass are pretty much interchangeable in these systems, excited (higher energy) states, act like particles with a larger mass.
I think the use of flavour here is quite okay, to be honest, I think it makes the concept easier to grasp than the rather boring word, "type". Flavour brings about connotations of things that are actually different, you get them thinking about food and you get their attention ;)
That's what I get for only reading the BBC's article. Thanks for the info!
It's useful not to rely on intuition with quantum mechanics.
So, note that "quarkonium" isn't a particle, but rather a class of particles -- a quark bound to its antiquark. A collection of quarks held together by the strong force is a bound state. Bound states of quarks are particles.
Quoting: "However, whereas the Higgs is not made up of smaller particles, the Chi-b(3P) combines two very heavy objects via the same 'strong force which holds the atomic nucleus together."
I hope the LHC building is designed to withstand the weight of these heavy objects!
"a lot of the mass of everyday objects comes from the strong interaction we are investigating using the Chi-b." WHAT?!?! the strong force causes gravity?!? i'm sorry gravity is an r^2 force, the strong force is far from r^2 force. so that's not even remotely possibly. and these guys are supposed to be particle physicists?!?
What started out as Philosophy and turned into Physics, now has gone back to be Philosophy again because it's too weird and difficult to understand.
-- By all means let's be open-minded, but not so open-minded that our brains drop out.
I think the use of flavour here is quite okay, to be honest
Actually, it's not, because flavour has a very distinct and very different meaning in this context.
Free unix account: freeshell.org
More particles??? hmm
WARNING, you are dangerously close to the event horizon of a black hole and are experiencing time dilation. Set your FTL to bacon patty melt.
Without that caviat, it's pretty misleading to call this a particle, when all we've really measured was an excitation state of already familiar particles. So do I have it right that even this combination of quarks has been observed before, and what's new is that we've never seen them so excited before? Well, good. I mean, surely we knew it was possible for the thing to reach a higher excitation state and we had a decent idea about what energy the whole system would have at that state. What I'd like to know now is this: Just how much of a surprise is this measurement? Did the standard model predict the precise energy we measured, or does the measurement add new detail or precision to the standard model? Gah, actual science is hard, but that can't be helped. Science journalism is shallow and uninformative, but that can - which makes it pretty frustrating. (This is one field where blogs are really way ahead of the traditional media.)
In the nomenclature of high-energy physics it _is_ a new particle, just as a proton is a different particle from delta+, even though for low mass quarks it can get a little bit more complicated because of mixing (for example the eta is a mixture of all the low mass quarks) the Chi_b(1S) has a very different mass than the Chi_b(3p), different decay modes and quantum numbers... From what I read of the paper (I just skimmed it) the value of its mass is in agreement with theory - note that to analytically calculate the mass of the system bound by the strong force is very difficult, it is only for the high mass quarks (charm, top and bottom) that you can get a simple model to work, conceptually the model is like two masses bound together by a spring as opposed to an inverse square law like gravity or electromagnetism. As far as I know nobody has really convincingly calculated the masses of all the light hadrons using a model, or successfully predicted the full spectrum of light hadrons and their decay modes - the problem is the strong force consists of the three charges (and anticharges) mediated by 8 quarks and the charges (quarks) are moving around at relativistic speeds - for heavy quarks the problem is simpler since you can use a non-relativstic model, and use a simple quasi empirical approximation for the complex stuff going on in the field...
Mass, not gravity. If there is bound energy, it manifests as mass. A compressed spring is ever-so-slightly more massive than a relaxed spring. The main place where this is noticed is with very strong forces, such as the strong nuclear force.
Mass != Weight
Yeah. Would you choose a neurosurgeon who pokes around people's brains in his spare time? I wouldn't.
This is not at all surprising, and agrees VERY well with theory. Yet another confirmation of the Standard Model. This measurement does decrease the error bars a good bit, so it's important, but not as important as if it were a new fundamental particle or a violation of the SM.
Not a sentence!
Flavour is the term used to describe the different types of quarks. The wikipedia article you link to gets into a more generalised concept of flavour, but that concept gets its name from the original use for properties that distinguished different kinds of quarks.
Add up the masses of two up quarks and a down quark, and you get something like 12 MeV, while the mass of the proton that is made of these three quarks is 938 MeV. The vast majority of the mass comes from binding energy and strong force interaction between the quarks, much more so than just the individual quark masses. Hence, better understanding of the strong force by examining more extreme cases that push the limits, like these higher energy bottomium states, can help give insight and test models that also explain where protons get their mass from.
Let's see, so there's two possibilities:
1) Particle physicists at the LHC made a very elementary error.
2) You are misunderstanding something.
Yeah, I'm going with #2.
Quarks normally group up in 3s; with a proton being two ups and a down, and a neutron being two downs and an up. Another form of quark grouping consists of a quark and an anti-quark of the same flavour, which is what's been observed here. And this is the first time that one of these pairs has been observed that consists of quarks with the beauty flavour. Other flavours of pair have been observed before, but its the fact that this one consists of beauty quarks that makes it "new".
So, in essence, {and pardon the food analogy} you're saying that most matter is like an 3-scoop ice cream cone - two vanilla, one chocolate, or two chocolate, one vanilla - and what they've found here is one scoop of double-mint truffle fudge, two scoops gold-leaf-covered Cherry Garcia? (ie, it's still an ice cream cone as expected, just with more exotic flavors.)
Don't tell me to get a life. I'm a gamer; I have LOTS of lives!
The quarks group in ways that are colorless. So you can have three quarks, if they are red, green, and blue, because those make white (no color). And you can have red and anti-red, because they cancel again leaving no color. That's how you get groups of two and groups of three.
You could also have a group of four, for instance red, anti-red, green, and anti-green. Or a pentaquark: two reds, a green, a blue, and an anti-red. They just have to all mix to white.
There's a reason why this property of quarks was called "color" -- the analogy is so perfect.
The Higgs boson is completely different to gravity and is only needed to explain why fundamental particles e.g. electron has a mass. To the OP who claimed there is no Higgs boson lets just say we have a 3.6 sigma peak which suggests otherwise!
The way the Higgs field gives mass is that the lowest energy state of the field is when the field has a non-zero value. This is very strange and very different from e.g. an electric field which has zero energy density when there is no field. This strange property means that, when you take all the energy out of the field, the field reduces to a non-zero value i.e. the Higgs field is not zero in the universe today but has a finite value.
Second the Higgs field is a scalar field which means that it has a magnitude but no direction. Again this is unlike any other known fundamental field: EM is a vector and gravity a tensor field. What this means is that while the Higgs field is not zero it does not have a direction so, unlike the other fields, it cannot cause a force (because these have a direction). Hence the Higgs field is not really at all like the poles of a magnetic field because there are no field lines as this would imply a direction and so are meaningless for a scalar field and there are no negative charges so no dipoles. When a particle is created it binds itself to the non-zero Higgs field filling the Universe and it is this "binding energy" which gives the particle its mass.
Gravity is a different force which couples to the 4-momentum (energy and linear momentum) of a particle. As you correctly state it is presumably transmitted by a massless spin-2 particle which is why it is a tensor field. However quantum theories of gravity don't work (you can make them but you have to put an arbitrary energy cut-off into them).
Note that the above is only a very brief discussion of the Higgs and misses out all the complexity, and beauty, of the spontaneous symmetry breaking process...but this post is already long enough!
The thing is we have the 'graviton' listed as the force carrier, but we have not seen or don't even really know what a graviton would look like, so the Higgs is almost and alternate / parallel description of the mechanism.
Sorry but this is just wrong. The Higgs mechanism has nothing whatsoever do so with gravity and is definitely not just some alternative description of it. For a start it is a scalar field with spin-0 and so cannot create a force because that requires a direction so there is no way at all that the Higgs can possibly explain gravity - although it does explain very clearly why energy and mass are related. I appreciate that you are trying to simplify things down for a more general audience but you went a little off the rails here!
From the article, "The beauty quark is also known as the bottom quark." Now I can't stop thinking about beautiful bottoms.
why didn't you read your own link? flavour has a very distinct and exactly the same meaning the op gave it in this context.
Thank you! That was so brief, clear and informative! If only real science journalism would sound more like your comment...