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The LEP Collider Will Be Closed Down
mukund writes "The Large Electron-Positron (LEP) collider will be dismantled soon, as this article on BBC News reports. The LEP is the world's largest particle collider and is built inside a 27km long tunnel. The collider has been used to confirm the existence of the Higgs particle unsuccessfully. A new project to build another larger collider is on the way. The article says, "According to commentators, whoever finds the Higgs first will probably win a Nobel Prize.""
Is that like the Presidential election was used to confirm the new President unsuccessfully?
Er, what does this mean? They confirmed it, or didnt they? What is the Higgs boson anyway, beyond the sketchy clues the article gives? Pointers from the physicists out there?
Thank GOD! now they can't create a black hole and suck us all in.
But really, why are they closing it down?? the more the merrier.
For more background information, see links:
Scientific American
Another description
Oh-So-Useful Slashdot Article
Uh, Keyboardist
There was a great story on All Things Considered yesterday, I think, about this. The guy they interviewed explained what was going on and why very clearly. I'm not into this much, but understood the basic concepts pretty well. For those in the audience asking "What's a Higgs?", here's a link to a Scientific American Article about the Higgs Boson. I tried to get to NPR's site to see if they have a link to the story, but the site is pretty hosed right now. I wonder why :)
"shop smart:shop s-mart" ash
Let a lower powered accelerator attempt to find the Higgs, I STILL don't believe it will be discovered, because it's been stated over and over 'we just need a little more power to find the Higgs boson!'. The problem is that all of these vast teams are lead by one or two scientists, who desperately want the Nobel Prize. Hence, good science is sometimes ignored in favor of the limelight... I'm just glad 'good physics' prevailed this time around.
I had hoped to talk about this on BottomQuark but lost all my research midway through the discussion. whoops. `8r) I wonder if there is such a thing as an amateur partical physics person....
--
Gonzo Granzeau
Gonzo Granzeau
"Nothing the god of biomechanics wouldn't let you into heaven for.." -Roy Batty
The Large Electron Positron (LEP) Collider is being shutdown to make room for the LHC (Large Hadron Collider). The LEP smashed electrons and positrons together (hence the name). The LHC will smach protons and anti-protons together. Protons and anti-protons are a thousand times more massive than electrons and positrons. Therefore, since mass and energy are equivalent (E=mc**2), the LHC will be able to reach energies many orders of magnitude higher than the LEP. The LEP is being shutdown because the LHC will use the same tunnel at CERN in the Alps that the LEP used (as a cost saving measure).
Quando Omni Flunkus Moritati
All these people seem to be complaining about scientists chasing the Nobel prize, implying that that's a bad thing to be taking into consideration, etc.
I mean, if you worked for several years at a company developing some sort of important software , wouldn't you be sort of pissed off if someone else came out with essentially the same product during an unforeseen server outage on your company's side?
The nobel prize is to a scientist as writing some piece of software like Napster or Linux is to a programmer - it provides:
It's "proof" that they accomplished something. Without said proof, even if you are very, very close, no one is going to give you any more money (at least not politicians - remember, sonny boy, these fancy partickal excellorators come out of my taxpayers pockets, and they ain't done one dang thing but ask for more money! Look at what happened to the Princeton Plasma Physics lab - they were close to actually getting a positive energy return on a fusion reactor (closer than anyone else), but since they weren't actually getting one, they lost their funding and their accelerator just sits there. I've talked to some of the physicists, and believe me, they are bitter about it.
Why is the Higgs so important?
Apart from being the last of the Standard Model particles to be discovered, it is also (via the so-called) Higgs Mechanism responsible for the generation of mass.
What?Well, just as the photon is the "carrier" of the electromagnetic field, the carrier (incidently, all such carrier particles are bosons - that is, have integer "spin") of the mass field is the Higgs Boson, and will be seen as evidence for either the Standard Model of Particle Physics, or (depending upon its properties, or indeed, existence!) for other competing models. As one might well imagine, the mass generation process is very interesting to Physicists, and Higgs discovery would certainly be worthy of a Nobel prize.
As to the closure of LEP - LEP has done some startling physics and has been an extremely successful endevour however you look at it (for a start, without CERN we would not have the World Wide Web!) The collaborative model of smaller states coming together to afford large scientific projects was the predessesor to the ISS, and even a couple of the US High Energy Physics experiments (such as the experiment I'm involved with, BaBar are going the same route.
Finally, don't forget that Physics is still a human endevour, and us Physicists need a pat on the back sometimes too!
- Dan
PS: Ed, get back to work!
I'm working at Fermi in production of the RunII CDF detector (as an engineer, not a physicist) and from what I hear, taking LEP down means we are nearly assured of the Higgs before LHC comes up - unless it is truely impossible at Tevatron's size, which seems unlikely, currently. Things here seem to be going quite well, imo.
To give a (very) rough explanation of the Higgs: when you smash things together with very high energies, you get a huge explosion (huge, considering it was started by one proton and one antiproton) and all sorts of fragments are produced.
However, we have to measure these fragments using very odd means, because it is mostly impossible to directly measure most of these things... you can only measure the effects they have on the relatively normal stuff we can build a detector out of. (if you build it out of these things, the detector would vanish in much less than a second...) So the more "normal" fragments are relatively easier to measure, because they interact more with the more normal detector.
In recent high energy physics history there has been a string of these things, Higgs is the next.
Someone said they first saw sci notation in 93, and I'm amazed. I'd heard in Junior High earlier than that... or did you mean something else.
Btw, Fermi has a significant linux community. Also, (from a bad memory and this isn't my department but) they have to filter the incoming data in realtime, keeping only the most interesting 1/millionth of it - and that data alone is a couple CDs/second worth of data. Lots o' bandwidth there...
Looking for freelance Actionscript (Flash/Flex) or ColdFusion work and/or freelance developers. Email me, put Slashdot
Anyway, here's the email:
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For some more (but brief) information about the Higgs boson read here
Some comments:
Maybe some of you wonder why these guys can't tell if they found the Higgs particle or not. Let me try to explain. It's all about statistics. Imagine you have two dices, one has the numbers from one to six on it. The other one you just know it has the numbers one to five and the last number can be any of 1 to 6, there might be e.g. another 2 or something. let's call this dice 'signal dice'. Unfortunately they look exactly the same and you can only read the number on top.
The Higgs is like the number 6 on the second dice.
ok. roll the dices. you get 3 and 5. Now you know there is at least a 3 or a 5 on the signal dice. Noone cares. again: 1 and 6. Wow.. do we have something? You don't know because you cannot tell which dice shows the 6.
The trick: if you roll a hundert times, you expect 100 * 2 (dices) / 6 = 33.3 times the number 6 if the 'signal dice' has a 6 and only 100 * 1 / 6 = 16 times 6 if the signal dice has no 6.
You see, a single (or a few) rolles don't help. Even if you see the 6, it might be the other dice. Unfortunately they cut the power to LEP so they cannot keep on rolling.
Actually only Aleph has 3.5 sigma excess in one channel Z*->H Z (H -> b + anti b), so that means pretty much nothing and they don't really trust their Monte Carlo (which provides the second dice :). That means they see something, but just have not enough data to really confirm the existence. NOrmally you do that with at leat 5 sigma.
Well, todays HEP collaborations are very large. Especially when it commes to LHC experiments. There is no single 'person' that is by any means able to actually 'find' the Higgs. My best guess is that, given the Higgs particle will ever be found, Peter Higgs himself might get the Nobel Prize.KdenLive/PIAVE - non-linear video editing
Hiya,
Not a usual poster on slashdot, but it seems that few/none of the other Higgs searchers at LEP are sticking their necks up. For the benefit of non-Higgs searchers in particle physics, and for those willing to wade through some details, here's a Higgs searcher's perspective on the story.
Unfortunately, the majority of the information presented on this has been to the public session of what is essentially an internal meeting of LEP. What the experiments (and the LEP Higgs group) have shown in their brief presentations are summaries of much more detailed work which is of course still ongoing (data taking only finished a few days ago).
The comments that I've seen in this forum from physicists are coming from what could be termed either the general community, or the competition. They reasonably point out that brief status reports of ongoing analyses have not convinced *them* that the Higgs is there, but unfortunately this was the structure of the forum in which the results were presented. Another interpretation is that we didn't properly anticipate confusion about issues that seemed obvious to the experts.
One common misinterpretation seems to be that LEP observes only 3-4 Higgs candidates, which is actually very false. This is just the number of events collected that really 'stood up' as extremely signal-like. In fact, hundreds of possible Higgs candidates were collected, and they are each given a rating on a "signal-like" scale. If you skim off the top few, you get four events, three from Aleph and one from L3. Up until very recently, Delphi also had one, but it dropped down on the signal scale after reanalysis.
As you drop down on the scale, to the point where you'd expect half of your events to be background and half to be signal, you expect 7 from background, and observe 14. The weight distribution agrees across the board with the signal distribution. These are divided among all four experiments and all search topologies. In fact, the sample was divided in several different ways for consistency checking purposes, and they all came out looking exactly like a Higgs signal. It gave us goosebumps to see the results of these tests.
If there's no signal, we've had a one in a thousand blip. There is a standard for discovery which requires that to be a bit less than one in a million. We are confident that, if it's real, we'd be able to reach that one in a million, and if it's not, that the effect would dry up. The whole point is that this is an exciting observation which we'd like to verify that is at the edge of our sensitivity. To do that properly would take six months of extra running, which all of the LEP experiments requested. The whole point is that it's not yet conclusive. The CERN management has been weighing questions of cost of running (in dollars and delay of future projects) vs chance that we did just get a freaky blip in the background, and has unfortunately decided not to take the risk. People will have the next 6-7 years to wonder if what we saw was real or not before it can be tested again.
At the moment, the most complete information is at the Physics Co-ordinator's Page.
A collection of all of the presentations at the public sessions of the LEPC meetings can be found here.
Cheers,
Pete McNamara