Slashdot Mirror
Princeton Student Finds Bug In LHC Experiment
An anonymous reader writes "A Princeton senior has found a bug in the hardware design for the Compact Muon Solenoid (CMS) experiment of the Large Hadron Collider (LHC). In the hardware used to record and capture events in the LHC, she discovered errors that were leading to the appearances of double images because of particle streams known as jets. 'Xiaohang Quan '09 was working on her senior thesis when she found a miscalculation in the hardware of the world's largest particle accelerator. Quan, a physics concentrator, traveled to Geneva, Switzerland, last week with physics professors Christopher Tully GS '98, Jim Olsen and Daniel Marlow for the annual meeting of the European Organization for Nuclear Research (CERN). This year, however, they also came to discuss Quan's discovery with the designers of the hardware for the Compact Muon Solenoid (CMS) experiment, which, as part of the Large Hadron Collider, has the potential to revolutionize particle physics.'"
Her last name is "09" and she is a "concentrator?" Who wrote this?
A slashdotter who didn't build his own computer is like a Jedi who didn't build his own lightsaber.
Guess LHC better get in for a checkup. Like so many major observatories of late, this one is also near-sighted. ^_^
#fuckbeta #iamslashdot #dicemustdie
then it goes from a bug to a systematic error, which can likly be accounted for when it comes to results
She just made her career, and rightfully so.
512 MB RAM, 20 GB disk, 200 GB transfer, five datacenters. $19.95/month.
if it moves, it's biology. If it doesn't work, it's physics.
"It doesn't cost enough, and it makes too much sense."
They are calling her "Gordon" and are scheming to get her to be the guinea pig in the resonance cascade scenario test.
if it smells, its chemistry, if it moves, its biology. If everything in the universe is based off of it, its physics.
Black Holes rock!!! End of the world here we come!
No wonder physics is phucked in the phucking head, their goddamned bug fixes are "revolutions"
It's quite clear that these issues will never cease. This is simply the result of the Universe preventing a causality paradox. If the LHC were turned on (Let there be light!) then existence as we know it shall cease to exist.
Oh yeah, I went there.
Their may be a grammatical error, misspeling, or evn a typo in this post.
I would have to say that this student will not have a problem finding a job after graduation.
CERN: Now Xiaohang, Sherry is going to show you around the place. She can answer any questions you might have about fringe benefits or dress codes or anything and I'll see you back upstairs when you're done, okay? Sherry, take good care of this young lady. She's one of the ten finest minds kin the country.
XIAOHANG: Someday I hope to be two of them.
Flexible bare-metal recovery for Linux/UNIX
It barely matters, as the tiny black holes engulf the detector, her, and us all!
Put this in terms the average American can understand. How much does this increase the odds of Earth-swallowing black holes being created? Isn't the LHC beam scheduled to hit full luminance sometime in December of 2012?
Learning HOW to think is more important than learning WHAT to think.
A Princeton senior has found a bug in the hardware design for the Compact Muon Solenoid (CMS) experiment of the Large Hadron Collider (LHC).
The bug was in the algorithm analyzing at the data from the CMS and not the hardware.
Yes, it's probably sexist to say it but women have some innate ability to debug code. I've seen this happen too much professionally to think of it as a trend. The evolutionary origins? I can't explain.
I swear to God...I swear to God! That is NOT how you treat your human!
Dude. You better hold your breath. You don't want your breathing to possibly open an inter-dimensional rift. We still need to know the basics of physics before we can be sure. Don't worry. It won't be long.
"When life gives you lemons, don't make lemonade. Make life take the lemons back!" -- Cave Johnson
The writeup is incorrect (obviously not up to Daily Planet-quality work here). Jimmy Olsen is a reporter, not a physicist. The physicist referred in the article is actually Lex Luthor, and the Large Hadron Collider is really a secret project to turn normal metals into Kryptonite.
(-1, Raw and Uncut is the only way to read)
until enough people / scientists are SURE nothing bad will happen.
The only way to know that is if they know exactly what will happen. And if you know exactly what will happen, what's the point?
Unfortunately there is always the nagging possibility that tiny black holes will fail to devour us all ... but that's a risk that can probably be insured. So you can't lose, right?
Perhaps you fail to realize the level of arrogance humans have, especially "scientists".
You are ignorant; the universe is already conducting high-energy physics experiments. They are called cosmic rays, and some of them are billions of times more powerful than the LHC. Yet the earth is still here. And your notion that we delay until we completely understand the laws of physics is comical. What do you think the LHC is for? It's to help us understand the laws of physics! You don't discover laws of physics by just thinking deeply. You discover them by experimentation.
Some universities call it concentrating on a subject rather than majoring.
That's because years ago, teachers found out most students don't concentrate on anything.
But this girl is definitely the exception, she's obviously concentrating very hard.
"All great wisdom is contained in .signature files"
via hardware verification with ACL2.
I hope this helps the LHC Experiment so it doesn't cause
a black hole to destroy THE UNIVERSE.
Yours In Physics,
Kilgore Trout
Yeah, no more research until we understand everything. Good idea.
We hope your rules and wisdom choke you / Now we are one in everlasting peace
This story makes me fall in love with science even more. Smart people think of ways to understand the world better, other smart people review it, find errors and discuss their finding with other scientists.
They have a discussion like adults, they look at the math, one side is correct and they correct their experiment and thank them for the contribution.
This is what the world is supposed to be like. Not like these fucking religois nutjobs, screaming at each other, arguning who has the cooler imaginary friend, without having even a halfway decent argument. They're just like "You're stupid!". "No, you are!". "No you!"
Science for the fucking win!
It all depends on where you work.
I've seen businesses make decisions on thousands of lines of code in meetings after meetings, where they don't actually bring a computer, nor a line of code in. They theorize. They ponder. They wonder. They question. Then they come out of the meeting, and tell the developer how he screwed up. The theory and the reality very rarely coincide.
I like to throw them, by giving them a dozen different yet plausible theories as quickly as I can. Different people will pick up on various ideas that I threw out to them. Then some will try to converge on a single idea, and fail miserably. It would be funnier if you could just slide a few swords across the table, and watch them have at it.
Of course, none of the theories I threw out in the meeting had any basis in reality, they were just fun to watch people fight over.
Solar flares.
Years ago, I actually proved to management, that solar radiation made one server crash, and didn't touch the hundreds around it. That was regardless of the fact that there was a 10 story building above it, and it was 30 feet underground, in a hardened bunker, surrounded by well grounded metal. It was the end result of a micro solar flare. I think we were lucky no one was standing there when it happened.
I'm a firm believer that theory is like being a lawyer. If you can convince enough people (or the right people) of it, it must be true.
Serious? Seriousness is well above my pay grade.
Just delays us nearer to 2012?
until you are SURE you have a better handle on the issues.
Maybe you should wait until you completely understand the basics of physics before you talk about man-made black holes wiping out our solar system?
"Wise men talk because they have something to say; fools, because they have to say something" - Plato
She'd also find all those bugs crawling around.
A different undergrad is going to CERN for the summer with her thesis adviser. You'd think they invite her after she stumbled upon this.
bugs cause the end of the world....AUGGH run away run away
There are at least 36 Slashdot comments so far, and not one of them is bitching about Xiaohang going over to America and taking all yer physicist's jobs/university places.
Yeah, unpaid research in Switzerland belongs to Americans, damn it! The INS should look into this "CERN" outfit.
Research has led to the discovery of the heaviest element yet known to science. The new element, Governmentium (Gv), has one neutron, 25 assistant neutrons, 88 deputy neutrons, and 198 assistant deputy neutrons, giving it an atomic mass of 312. These 312 particles are held together by forces called morons, which are surrounded by vast quantities of lepton-like particles called peons. Since Governmentium has no electrons, it is inert; however, it can be detected, because it impedes every reaction with which it comes into contact. A tiny amount of Governmentium can cause a reaction normally taking less than a second, to take from four days to four years to complete. Governmentium has a normal half-life of 2-6 years. It does not decay, but undergoes a reorganization in which a portion of the assistant neutrons and deputy neutrons exchange places. In fact, Governmentium's mass will actually increase over time, since each reorganization will cause more morons to become neutrons, forming isodopes, not to mention multiple oxymorons. This characteristic of moron promotion leads some scientists to believe that Governmentium is formed whenever morons reach a critical concentration. That hypothetical quantity might normally be called 'critical mass' but, in this unique case it is known as 'critical mess'. When catalyzed with money, Governmentium becomes Administratium (Am), another just-discovered element that radiates just as much energy as Governmentium since it has half as many peons but twice as many morons.
The society for a thought-free internet welcomes you.
Coincidentally, Quan was also nominated for Princeton SILC, or "Senior I'd most Like to Collide with" in '09...
its not really a design flaw. Basically its a minor bug in the algorithms (if I'm reading it right, the article is very confused to say the least) which allow physicists to reconstruct the energies of hadronised partons. Now we can do it a bit better and make slightly better measurements. This software we know isnt optimal, it requires a great deal of knowledge to write and to be honest a major part of the effort in the earily days of an experiment is improving the reconstruction software with fixes such as this. And there will be many more such improvements. Bugs here do not pose any danger because the software is run *after* the event has occured so it cant effect the event, just our understand of what actually happened.
Also just to make clear that the LHC and CMS are very different things. The LHC is the accelerator and its what makes the particles go very fast. CMS is a detector, it just sits there and records what happens in the collision. CMS is built and designed by a completely different set of people to the LHC. CMS doesnt need the LHC to function and the LHC doesnt need CMS to function but they are a bit pointless without the other.
Genius! All the reused memes get +5 Funny, but the truly witty don't get bumped up.
until enough people / scientists are SURE nothing bad will happen.
The only way to know that is if they know exactly what will happen. And if you know exactly what will happen, what's the point?
If I flip a coin, I don't know if it will land on heads or tails. I know it's not going to turn into a unicorn though.
It's little-known that Bush also found some critical errors in Fermilab calculations.
Every time I see a story about the LHC, I'm always glad I'm far away from it, because I don't want to have anything to do with colliding large hardons.
Mod parent funny. I can't.
Nice post, Hork_Monkey. :)
Let q be a radix > 1. I am in ur base-q, killing 10 d00ds.
Which imbecile tagged this defectivebydesign? Are you a *AA shill trying to dilute the meaning, or just plain stupid?
1. Yep, the universe is conducting huge physics experiments, but very VERY far away from where we are, not in the middle of Europe
2. Thinking deeply is always done FIRST than experimentation (at least in the scientific method), when you first make an hypothesis and then predictions (Wikipedia even describes it as "logical thinking" and "calculations") before experimentation, which is the last step.
3. I wrote that post because it is obvious for any observer that there are flaws in the LHC. They have already broken a magnet of it, and now a student finds a flaw in one of its calculations. Maybe it doesn't turn into a big black hole, but it can explode and/or cause any other tragedy.
Never ever underestimate Murphy's Law, we need to learn to be less arrogant.
- Human knowledge belongs to the world
If only there were some system, based in language, that allows you construct sound theories from explicitly accepted assumptions, and some rules.
Humans have been breathing for thousands of years without rifts opening, so I think breathing is safe. How many microscopic black holes have been man-made before?
- Human knowledge belongs to the world
Maybe I shouldn't get out of bed tomorrow until I'm SURE nothing bad will happen.
I never said that. You totally misread my post and probably the people that mod you up didn't even read it.
What I said is that more research should be done BEFORE we turn on the LHC. Fermilab is not creating micro-black-holes, but advances in "trapping" the Higgs Boson where made on it 10 days ago.
There is still a lot of knowledge we can get without playing with this big buggy monster, at least until we are sure it's not buggy and that the calculations where right.
- Human knowledge belongs to the world
I'm sorry to be the one to tell you that there's already black holes slowly destroying THE UNIVERSE. They're going to the whole thing eventually; there's a giant one busily destroying THE GALAXY right now. Maybe you're more concerned with the microscopically small part of THE UNIVERSE that is necessary to sustain your own life?
Yours in Pedantry,
Ekhben
Yep, the universe is conducting huge physics experiments, but very VERY far away from where we are, not in the middle of Europe.
The earth is constantly being bombarded with high-energy radiation. Some of that bombardment happens above Europe. The ionosphere is about 50km-1000km away from the earth's surface. What exactly do you mean by very VERY far away?
"Wise men talk because they have something to say; fools, because they have to say something" - Plato
Maybe it doesn't turn into a big black hole, but it can explode and/or cause any other tragedy.
More likely is that any power plant you name could explode and cause a tragedy.
I know, let's shut down every single power station in existence!
At least that would have the side effect of downing the internet and we wouldn't have to listen to any more of your nonsensical tripe.
"Wise men talk because they have something to say; fools, because they have to say something" - Plato
There is still a lot of knowledge we can get without playing with this big buggy monster, at least until we are sure it's not buggy and that the calculations where right.
We are sure. It's only you (and a couple of other crazies) who think otherwise.
"Wise men talk because they have something to say; fools, because they have to say something" - Plato
Humans have been breathing for thousands of years, but nobody has ever yet simultaneously breathed and thought about twelve thousand four hundred and ninety-six books about fruit all connected together by friendship bracelets.
I had to hold my breath while writing about that just now in order to be able to think about it without risking the entire universe imploding into a singularity.
Let me know if you manage to think about it and breathe at the same time. If we can get away with that, I think we can safely turn on the LHC (as you can surely agree that the whole universe imploding is a substantially worse risk than a single black hole or explosion).
"Wise men talk because they have something to say; fools, because they have to say something" - Plato
If I flip a coin, I don't know if it will land on heads or tails.
They can land on their edges, too. Also, how did you come to that conclusion, without somebody trying it first?
That guy at Tunguska already showed the effects weren't that that serious.
"The Adobe Updater must update itself before it can check for updates. Would you like to update the Adobe Updater now?"
There's no call for labeling scientists 'arrogant' simply because you lack belief in their silly superstitions about 'logic' and 'reason'.
Power does not corrupt - power attracts the corrupt.
This is going to go down as a quirk discovery by a Quan who is not a Quark....
Either way, looks like she concentrated pain on them with her high-QUALity, QUANtitative analysis... Now, if QUANtum Mechanics is in her repertoir... and she makes a substantial amount of money, she can qua-qua-qua duck-waddle all the way to the bank...
OK, I'll QUit, now...
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
There's a lot of that going around.
It's little-known that Bush also found some critical errors in Fermilab calculations.
Oh but seriously, Jimmy Carter's background as a nuclear physicist and engineer became somewhat useful during the Three Mile Island nuclear reactor partial-meltdown.
On April 1, President Jimmy Carter arrived at Three Mile Island to inspect the plant. Carter, a trained nuclear engineer, had helped dismantle a damaged Canadian nuclear reactor while serving in the U.S. Navy.
That Onion story also reminded me of this SNL sketch from 1986 or so. Some jokes are eternal...
W
-------------------
This is my SIG. There are many like it, but this one is mine.
Trying to be funny just makes you sounds quanceited.
...whoops O.o
Rampant carbon sequestration destroyed the Dinosaurs' tropical paradise. I'm here to help repair the damage.
Years ago, I actually proved to management, that solar radiation made one server crash, and didn't touch the hundreds around it. That was regardless of the fact that there was a 10 story building above it, and it was 30 feet underground, in a hardened bunker, surrounded by well grounded metal. It was the end result of a micro solar flare. I think we were lucky no one was standing there when it happened.
People, the BOFH exists, and he's a Slashdotter!
Nice to meet you, sir, I'm a huge fan :) can I get your autograph?
No problem is insoluble in all conceivable circumstances.
Good post except you could have left off the "You are ignorant"
... that's Ali G.
At Arvard, no less!
sig? Oh, that sig...
1) She's paying to go to university, so she's not "stealing" anyone's job
2) You assume she's not a US citizen based purely on her name
Why is this newsworthy? There was a bug (a bug!) in the LHC software? The bug was found by an _undergraduate_? An undergraduate _girl_?
No - an undergraduate girl from _Princeton_!
-as seen from Yale, anyway.
Fiat Lux.
OK risking off-topic now... but it may be me or are the Chinese really taking over? The last few years when I read about US based research, particular fundamental research, almost always I see Chinese names on the list. Often only Chinese names, or the main researcher being Chinese.
Now I know there are indeed more and more Chinese, particularly mainlanders, going to the US to study and do their PhD. Here again it's a Chinese student that is in the news for some outstanding achievement.
Where are all the "native" Americans gone? (with native I mean born and raised in the country, not only the "native Americans" kind of natives). Why don't we see more American (as in English or otherwise European) names on this kind of research?
Actually that is pretty typical for most good grad students - just because it is the LHC does not make it special. In fact I really fail to see how this is news is of any interest outside CMS. A lot of what grad students do to get them started is to check what has already been done - I have a grad student doing this right now and it looks like he's found a problem too with some online code so should I submit that as newsworthy to Slashdot too? If so there are going to be a huge number of "look I found a bug" stories...
Even when not just checking they are usually concentrated on particular parts of the detector and it is quite common for them to spot subtle problems that others have missed. I did it several times when I was a grad student and now, as a prof, I'm finally where I can make the errors for future grad students to find!
I'm a firm believer that theory is like being a lawyer. If you can convince enough people (or the right people) of it, it must be true.
This is why theoretical physics is considered so difficult. People are irrelevant: you have to convince the Universe that it is true.
Maybe we should wait 'till we completely understand the basics of physics...before we turn on something that in the worst case (black hole) will wipe out our solar system.
Ok, first some physics that we do know: converting the Earth into a black hole will not destroy the solar system, in fact even the Moon would likely be unaffected. The Earth's mass would still be there just considerably more compressed.
Next our understanding physics is not improved by sitting around with our heads in the clouds waiting for a bright idea, nor is it improved by debating it. No matter how smart an idea it must be tested by experiment. So you cannot 'wait' for our understanding to improve you have to do experiments exactly like the LHC to figure out which of the miriad of possibilities is correct.
Finally we know it is safe because we are not sitting inside an Earth-sized BH already. Cosmic rays strike the Earth, sun, planets and every start in the galaxy with energies many times greater than the LHC and yet we have yet to see any of these collapse into a Black Hole.
I think the LHC has already created Black Holes..... Money Holes, that is.
Knowing Google's lust for data collection, the Soviet Union is still alive and well inside the psyche of Sergey Brin....
You must be new here.
JoeBuck:
On the other hand, cosmic rays arrive now and then, not in fiercely concentrated streams. Have you never heard of resonance cascade phenomena?
Come on, 99% of the time you don't *know* what will happen if you do something, but can be quite confident that a lot of things will *not* happen at all!
Say, you are at a swimming pool in a health center in New Your.
You dive in: you may not be 100% sure you'll not be hitting somebody else. You can be quite confindent you're not going to find yourself in the middle of the Mojave desert, though.
"If you haven't done anything in physics by the time you're 21, you never will."
I've been told this quote comes from Heisenberg, and at the time I heard it, I thought it was a load of crap. However, the idea is correct. If you want to be a physicist, you have to be able and willing to jump into research right at the beginning (as an undergraduate), or you'll probably never do real research. Of course, most undergraduates don't end up finding bugs in code which has been checked by dozens of postdocs and grad students.
For something that cost almost 1 billion dollars to make, you would think they would check and recheck and recheck and recheck and recheck and recheck and recheck the calculations. How many engeneers can you pay to review your code for you with 1 billion dollars.
Of course if you live in Montreal Canada, the answer is 1 , he'll charge you 800 million for it, give you back 400 million cash under the table, and keep 400 million for himself....that's how crooked they are here.
"physics professors Christopher Tully GS '98, Jim Olsen and Daniel Marlow"
I feel so much safer knowing Jimmy Olsen is on the case. What could possibly go wrong when you have Superman as back-up when investigating a world-ending device?
[pondering the possibilities]
Sure. Would you mind meeting me in the datacenter? Yes, right through that door. No, disregard the sign that says "Caution: bare live wires" and "Beware of the Leopard". They're just ... a formality.
Draek looks a little confused, yet star struck, and walks straight into the datacenter. 30 feet in he hears the slams of the firedoors, followed by click of the contactors as all the lights go out.
"Oh, do mind your step, we may have a few loose floor tiles" Smythe says over the intercom, watching carefully with the infrared cameras.
"Wha..."
{{BOOM}}
{{CRACK}}
"MY LEG! I'VE BROKEN MY LEG!"
Really, we can't have any witnesses now, can we. PFY, would you mind letting the leopard out for a run, I think he's hungry.
Leopards are amazingly useful for both planning offices and datacenters. If you don't already have one, you should really consider it. Especially if you have such BOFH tendencies as I do.
Serious? Seriousness is well above my pay grade.
Scientists are constantly double-checking each other and making improvements. Especially in the case of one of the largest engineering projects ever built there will be improvements found.
ATLAS is clearly the better detector in the first place :smug:
One of my favorite assignments to give is: "Find an error in the textbook." It gets the students to actually read the book closely. (Of course, I need to be sure that there is at least one error in the book before giving that assignment. That usually isn't too difficult. Most undergraduate texts have numerous small errors.)
I am the only person who knows the true cause of gamma-ray bursts.
They are alien civilizations who just switched on their LHCs.
That that is is that that that that is not is not.
It is. Research is known to cause cancer in lab animals.