Talk:ATLAS experiment

Mission accomplished!

I hereby declare "Mission Accomplished!" on the request for expansion. -- SCZenz 22:34, 15 July 2005 (UTC)

ATLAS

Good job! Title might want to adjust so people can get to it easier. PS: A collegue of mine worked on ATLAS I believe in New Mexico?

Cheers Scott 19:36:42, 2005-08-27 (UTC)

People work on ATLAS everywhere, more or less.. ;) Anyway, this is the proper name of the experiment, but I will think about a helpful redirect or two, maybe one without the capital S. -- SCZenz 20:14, 27 August 2005 (UTC)

• :I think the whole project was dis-assembled and re-assembled. Moved?
• :Anyway I was thinking of making a page on Torroids, but I'm too lazy, LOL Please do keep in touch and thanks for the SLAC, thingy title change. Worked out well, Good work. Scott 00:33:34, 2005-08-30 (UTC)

Nice pic of the ATLAS pit

Nice pic of the pit, Reminds me of SLD AT SLAC. Time to bring the Mark detector over? It was built torched and all, assembled in Japan, then unassembled and transported by barge into SF Bay then shipped by truck down 280 to Slac, Then Reassembled retorched moved 90 degrees in the pit after assembly, in the pit of SLC then was again commissioned and operated in the 90's, now just sits there in building 752. SAD Scott 01:53, 6 October 2005 (UTC)

Good!

Good! I don't understand half of what I just translated but I definately prefer this article to the one yesterday on the music video. Mithridates 17:30, 24 November 2005 (UTC)

GCT

Looks like when they were renovating Grand Central Terminal...

Black Holes Created

1. Nice to see black holes are discussed. It is a topic of Science Fiction as a great mass that automatically sucks all matter near it into it. In fact, any star that becomes a black hole cannot have more mass than that star had, and still has the same orbital properties due to the same mass, but it would be smaller with an event horizon where light cannot escape. This means, you can orbit a black hole like a planet and be safe, except for possible radiation hazards.

2. So, should a particle accelerator produce black hole effects due to the Universe have several dimensions, they will not be a hazard to anyone, and in Science Fiction it would have the Earth sucked up into a miniature black hole.

3. The fun part, is the physics people start having pet black hole projects.

Protection

Sorry, folks: feature articles make a particularly tempting target for the vandals, I guess. I've blocked the relevant IP, but he (I'm sure it's a fourteen-year-old boy, or possibly younger) may return from a friend's house, or from school, and so I've protected the article. Let's give it a day or so. DS 13:27, 25 November 2005 (UTC)

There is a typo in the text: "Curent CP-violation experiments". Can an admin fix that? Povmec 13:38, 25 November 2005 (UTC)

Done. the wub "?!" 16:32, 25 November 2005 (UTC)

Make that unprotected, today's featured article should remain unprotected if at all possible. The vandalism on this is no worse than normal. the wub "?!" 16:39, 25 November 2005 (UTC)

Year the Cyclotron was invented

We appear to have two conflicting sources of the year the cyclotron was invented.

Source 1: 1931 - Nobel prize website [1] Source 2: 1929 -Lawrence Berkley National Laboratory website [2]

Then there are several other sources that list the year as 1930. While searching through a list of reference, however, I found that the majority of dates point towards 1929, such as the Nobel prize website which also appears to be more of a reliable source (in my opinion) therefore I feel we should stick with the 1929.

Other examples of 1929: [3] [4]

Looking further, into the last link I gave, it appears that while the cyclotron was invented in 1929 but was not actually put into production until 1930, which is probably where the discrepancies in the dates come from.

Also, according to PBS.com [5], it further explains that in 1929 Lawrence already had the idea for the cyclotron in 1929, had the go ahead to build it in 1930, and had a working one in 1931. Therefore I will edit the page to somehow include all three of these dates. Cowman^Talk 20:19, 28 November 2005 (UTC)

Ah, I just looked back at the article and found that there is only mention of the cyclotron being built - should we then just leave it at that and not include when it was invented (1929 or 1930)?. Cowman^Talk 20:21, 28 November 2005 (UTC)

Recent reverted changes

Bunchofgrapes asked me to review these changes, which he reverted. They were obviously made by someone knowledgable, so I would like to explain why I am not readding any of them:

1. The changes from American to English spellings are in violation of Wikipedia:Manual of style#National varieties of English. There being no preference in how to spell it otherwise, the article defaults to the first contributor's spellings and should be consistent.
2. The addition of NA48 and KTeV as current experiments isn't neccessary, since they are no longer running. I'd still link them if they still had articles, but they don't.
3. The breakdown of the Standard Model will occur at high energies, because the model violates unitarity at those energies. The statement doesn't require "physicists believe" because it's not a guess about physics, it's a known fact about the model.
4. The "current energy frontier" is a bit subjective. On the one hand there are occasional events at the Tevatron in which the partons have a total center-of-mass energy of >1 TeV. On the other hand, they're too rare for anything to have been observed about them. I prefer the way it is because it's less confusing (Tevatron <-> TeV), but I admit that point is debatable.
5. The graviton is not in the standard model, and if you re-read the sentence carefully, it says that all standard model particles except the Higgs Boson have been found. No mention of the Graviton is required.

Please respond here if there are any more questions about the content. Thanks. -- SCZenz 19:45, 1 December 2005 (UTC)

Okay, I'm confused. Point by point: 1) Right. 2) Right. 3) The anon was the one who removed "physicists believe"; my revert put it back. 4) Uhh... over my head. 5) The anon was the one who removed mention of the graviton; my revert put it back. —Bunchofgrapes (talk) 20:35, 1 December 2005 (UTC)

Ok, I think I got confused about which way some of the changes went. What I wrote above is right; I'll go back and restore any changes that I agreed with but was confused about. -- SCZenz 05:17, 2 December 2005 (UTC)

Restored points 3 and 5 to the anon's changes, which agree with my views above. -- SCZenz 05:19, 2 December 2005 (UTC)

Reading the article about spellings you will note the line that articles about "European Union institutions and documents" shoud use "British, Irish and Maltese English". The ATLAS experiment is a CERN experiment and CERN is a European institution. Therefore by your rules the article should use English and not American spellings. -- 5th December 2005

Actually, that's an example of an article titled "European Union institutions and documents." I fear you can argue this either way. ATLAS is in Switzerland, and they spell it "metre." But they also don't have English as a national language, and spellings in other languages aren't the issue. But it's in Europe, and done at CERN, whose membership includes Great Britain (and not the U.S., which is only an observer). But it's a worldwide collaboration, and the majority of the institutions from English-speaking countries are in the United States. I'm not sure which is right; if there are other opinions in favor of changing the spelling, I'm willing to abide by that. -- SCZenz 23:36, 5 December 2005 (UTC)

I think it's better to leave articles in their status quo states. I'm very tempted to say "SCZenz, you did so much work to improve this article and you should have the sole right to choose", but I think that's the sort of stance that encourages style-warriors to make a few improvements to an article just so they would then have the "right" to change English styles (or, shudder, BC/BCE). In short, stability in this regard strikes me as more important than making sure all the articles about Europe use the British style.—Bunchofgrapes (talk) 00:15, 6 December 2005 (UTC)

ATLAS is actually not in Switzerland - it is in CERN which straddles the French-Swiss border. In fact IIRC the ATLAS pit site actually has a French exit. CERN is an international organization much like the UN. Swiss authorities need permission before they can actually eneter the CERN site. The standard of English used at CERN is international English which does not use American spellings. Seems pretty cut and dried according to your own rules.

You're twisting the facts a bit, which annoys me. Switzerland is still Switzerland, regardless of their giving land for use by an international organization. I didn't know there was a French exit to the ATLAS pit site; I certainly know that the main entrance is in Switzerland, and so is the pit itself. (The detector is located in many countries, at the moment, including downstairs from my office.) None of this is important, though. I think you're actually right. Although I couldn't find a general standard on CERN English, I did find this in the style guide for the IT division: "CERN is a European institution. Use UK English spellings (eg -ise endings – realise) as the rule." [6] I can think of no compelling reason to worry about it either way, so I don't care much; and since you asked, and make a going point about CERN's language, I will change it. -- SCZenz 23:43, 6 December 2005 (UTC)

Please disregard the irrelevant and unnecesarily harsh material I've struck through above. -- SCZenz 07:27, 7 December 2005 (UTC)

Isn't 'technicolour' linking to technicolor(physics) overdoing it? I must admit I dont know the spelling used in the first publishing of technicolo(u)r, yet one can assume it would be 'technicolor'

Well, it seems to me like the word Technicolor gets more google hits than Technicolour by a pretty good margin, but when you had +physics the margin is only about 100,000 to 15,000. That implies it's spelled according to the local spelling, which means -our per the above. The bottom line is that I, personally, just don't think it matters. -- SCZenz 16:39, 16 December 2005 (UTC)

Acronym

Is that acronym still in use? I can find it nowhere on any atlas sites, and I tought it was more or less dropped as a bit silly.

What acronym? -- SCZenz 16:39, 16 December 2005 (UTC)

If you mean the name of the experiment, it's not used often because it is silly. But it's still the name of the experiment, and gets mentioned every so often. -- SCZenz 16:40, 16 December 2005 (UTC)

Full detector image

Great article! May I suggest you the use of a full detector image? Many people don't have an idea on how all this parts are bound together. Check for example http://atlas.ch/atlas_photos/fulldetector/fulldetector.html

We can't use CERN images, because they release them for specific purposes (upon request) rather than under GFDL. It's a real bummer. Thanks for the suggestion, though. -- SCZenz 23:48, 3 January 2006 (UTC)

Returning from a trip there...

Advises to other people who would try this:

• Get a wide angle. When I say wide, I mean wide. My photographs were taken with a 20mm focal length and it was somewhat limited (not a chance to get a photograph of the whole detector when you stand in front of it, for instance)
• It is quite comfortable for Human eyes, but quite dark for a camera. I used a 3200 Ilford film because I had little time to stay there, but I would advise a tripod.

The ideal would be to have a tripod which allows panoramic mosaic photography (that is, the rotation centre should be on the nodal point of the camera). Rama 00:20, 3 March 2006 (UTC)

At the Compact Muon Solenoid I uploaded some images for example a full detector figure. Dave Barney, who is the leader of the CMS outreach group write me, that we can use it. See: commons:Large Hadron Collider. It would be good, if the ATLAS images would be free as well. -- Harp 10:26, 20 March 2006 (UTC)

Did you manage to get him to license it under GFDL...? -- SCZenz 19:48, 20 March 2006 (UTC)

Here are written: "All photos and movies are completely free to use, but we do request that if you find something useful (or if you have any suggestions as to how something could be improved), please send an email to cms.outreach@cern.ch"

It means these are Public Domain, aren't they? Do you think, that if these are free to use, it is includeing, that I am allowed to make an other picture using the picture from here? This picture I made from a picture from the CMS site. -- Harp 13:06, 22 March 2006 (UTC)

Oh, I think that's fine. I forgot that CMS licenses its stuff more freely than the rest of CERN. Unfortunately, I don't think the same is true of ATLAS. -- SCZenz 18:30, 22 March 2006 (UTC)

Actually when we generated some of the ATLAS images the idea was to deliver them *absolutely freely* for any use. Although we don't say that explicitly on the ATLAS webpage. We'll take care of that soon. Anyway, you can use any of these images on the wikipedia webpage or anywhere else without any problem. BTW, check out the new atlas multimedia page. -- Jppequenao 20:43, 12 December 2006 (UTC)

I emailed to ask about licensing since I can't find any mention of it on the webpage. — Laura Scudder ☎ 18:32, 2 April 2007 (UTC)

So I was told that for ATLAS images you still have to go through the CERN press office, filling out this form to ask for permission. That would mean we can only use images that we can also come up with a fair use rationale for. — Laura Scudder ☎ 14:55, 23 April 2007 (UTC)

Charged hadrons

At the LEP detectors and the CMS the charged hadrons reached the hadron calorimeter, not only the neutral hadrons and the EM calorimeter stops only the electrons and photons (and perhaphs less energetic charged hadrons). (See the LHC Slice picture at CMS article and the animation you can reach from there.) The article suggests that at the ATLAS the charged hardrons are absorbed in the EM calorimeters. I think it's not so. Could you fix it if I'm right, my English is not perfect. -- Harp 15:19, 22 March 2006 (UTC)

Yes, you're right. I figured just deleting the word neutral was the best fix. ;-) -- SCZenz 18:33, 22 March 2006 (UTC)

Other: I think about the black hole at ATLAS need a source of information. How much is the possibilite accepted? -- Harp 16:03, 22 March 2006 (UTC)

It's an idea that comes out of the theoriest of large extra dimensions as put forth by Nima Arkani-Hamed and others. There have certainly been talks about it; although I don't know in what sense one can claim one theory is more likely than any other, I think this one is seen as a long shot. In any case, having a source for it would be good and I'll look for it when I have the chance. -- SCZenz 18:33, 22 March 2006 (UTC)

I linked to the only two papers on black holes I found on the CERN document server. They both seemed pretty accessible and clearly written, but the low number of papers does seem to indicate a long shot. — Laura Scudder ☎ 18:22, 2 April 2007 (UTC)

EM cal resolution

The EM cal angular resolution is actually $\Delta \phi =.025,\Delta \eta =.025$ where $\eta$ is the pseudorapidity (not $\theta$). See http://www.cern.ch/Atlas/GROUPS/PHYSICS/TDR/physics_tdr/printout/Volume_I.pdf page 13.Rotiro 06:26, 4 April 2006 (UTC)

You're right of course. However, I'd like to avoid introducing pseudorapidity in the article. Any suggestions for making this more correct without making it more complex? -- SCZenz 21:24, 4 April 2006 (UTC)

Well, I don't know. You could just reference pseudorapidity. Say "$\Delta \eta =.025$ where $\eta$ is the pseudorapidity." I don't know if that would be useful. Maybe you're right. Rotiro

If you have to introduce pseudorapidity you could say "coordinate describing the angle relative to beam axis". That way you don't have to click on anything to have some idea of what it's about, but if you want to know what it actually is you can click. Speaking here as someone who just discovered what pseudorapidity was. — Laura Scudder ☎ 18:17, 2 April 2007 (UTC)

Completion schedule

This article states "The construction is scheduled to be completed in June, 2007.", does anyone know the current schedule for completion? I presume it's been delayed and not online yet. 58.161.49.182 14:13, 19 July 2007 (UTC)

Ok I checked the ATLAS experiment page itself and it stated "Starting in mid-2008," which is what I'm now going to change it to. Master z0b 05:19, 20 July 2007 (UTC)

Vacuum?

I had always been under the impression that particle physics experiments required vacuum in which to operate. If that is true, does CERN anticipate pumping out the entire ATLAS chamber?! Looking at the picture of ATLAS posted on [APOD] on 2008-02-25, that looks like a pretty huge space to have to reduce to vacuum! dafydd (talk) 16:28, 25 February 2008 (UTC)

Indeed, it does need to be under vacuum. No idea how long that takes to pump out. — Laura Scudder ☎ 16:44, 25 February 2008 (UTC)

The beam pipe is the only part in which there will be a vacuum. The pressure will be 10^-10 torr, from Atlas factsheet 5. So luckily there is no need to pump out the whole atlas cavern. — betatim 17:06, 20 August 2008 (UTC)

Time lapse video

I made http://www.youtube.com/watch?v=kVrUR_SOykk from the images captured by the atlas eye. Seeing it "grow" fascinates me, almost as good as visiting it, maybe even better since the cavern has been very full for a while now. Would it be appropriate to link to it in the "External links" section? I made it to show some friends how huge atlas is. Not sure about the licensing of the images? — betatim 17:06, 20 August 2008 (UTC)

Hall of fame

This article is very well written and contains valuable information. Much better than what I have read in many PhD theses and on the official ATLAS website. The only thing I dislike, is the emphasis which has been given to the groups which have developed the transition radiaton detector used for tracking in the inner detector. If you have a look on publications of the ATLAS collaboration, you will see a list of thousands of individuals originating from hundreds of different institutes. So instead of focusing on the involved institutes for a single part of the ATLAS experiment, a new category should be introduced which names alls institutes and their contribution. The according information should be removed from the main text, which would also help to have a clear structure which is easy to read.

May I add that this section is incomplete, incorrect and contains ill defined statements. TIn my opinion it should be removed. —Preceding unsigned comment added by 128.141.84.28 (talk) 15:31, 27 May 2010 (UTC)

Excellent article

Congratulations, editors - this is an excellent article. It is accessible to readers of just about all levels. The background and history sections are readable by almost anyone and then it gets more and more into the physics. Bubba73 ^{You talkin' to me?} 23:20, 14 August 2014 (UTC)

Sonification of Higgs candidates

Cat6 mgg126p5 pTt70

Hi, a sonification of Higgs candidate events was just uploaded (I'm embedding it here). A detailed description is at User:Cas ssc/sandbox. Perhaps we can find a way to insert it here or in some related articles? -- Daniel Mietchen (talk) 21:41, 21 June 2017 (UTC)

I don't think it is useful in encyclopedic articles. --mfb (talk) 13:20, 22 June 2017 (UTC)

Detector or Experiment?

This article refers to the ATLAS experiment, but in the second section ATLAS is described as follows:

"ATLAS is 46 meters long, 25 meters in diameter, and weighs about 7,000 tonnes; it contains some 3000 km of cable. The experiment is a collaboration involving roughly 3,000 physicists from over 175 institutions in 38 countries."

To me, this seems a bit precise, since the first sentence is definitely a description of a detector, a mechanical object while the second sentence describes something more vague, an "experiment" or a "collaboration".

So which is it? Is ATLAS both an experiment and a detector? Can someone clarify this for me? — Preceding unsigned comment added by 128.141.46.236 (talk) 08:04, 12 August 2017 (UTC)

It is both at the same time. There is also the ATLAS collaboration, the people who built the detector, operate it and analyze its data. "ATLAS" can refer to the detector alone or both detector and collaboration together. I changed the article text to "The ATLAS detector is 46 metres long [...]". --mfb (talk) 03:19, 13 August 2017 (UTC)

This is still a problem for this article. Based on the comments above, I feel it would be best to distinguish more clearly the detector from the program operating the detector. I propose the terminology "ATLAS detector" or "ATLAS program". The term "experiment" seems like it is being used in a colloquial way, and it is ambiguous with respect to the aforementioned distinction. It also provokes the question, "what is being tested?" (presumably as part of the program?), which I do not see a direct response to, making the article less readable. While this is an interesting question and within scope of the article, I don't have that answer. Someone else may be able to provide it.

I'm going to attempt to fix the ambiguity that I can in the article, but for the reasons I mentioned, I also suggest renaming the article to ATLAS (particle detector). 96.40.48.159 (talk) 11:04, 3 October 2019 (UTC)

Ok, changes made. The only thing that seemed like a potential problem was the phrasing "experiment pit", which I changed this to "detector pit".

I could be wrong here, but it seems like if I am, then the terminology "experiment" should probably be listed on a disambiguation page like experiment (disambiguation), and should point to something like particle detector. 96.40.48.159 (talk) 11:37, 3 October 2019 (UTC)

I disagree with your changes (and reverted them). "ATLAS experiment" is the common name. "Detector" typically refers to the physical hardware in the underground cavern only, in many cases where you changed it this is not accurate. "Experiment" is more inclusive. It can refer to the detector itself, the detector and associated support infrastructure, or the whole thing including the collaboration, software, computing infrastructure and so on. --mfb (talk) 20:53, 3 October 2019 (UTC)

I think the as-is status is an improvement from where we started (better about distinctions), but it is still never really explained what "particle detector experiment" means to the reader. What hypothesis is being tested? I understand that "ATLAS experiment" and "ATLAS Collaboration" may be official terms, but they aren't really defined before being used, and they are only used sparingly in the text (and certainly not for the title). What I feel is still a problem is the extensive use of the word "experiment", when it is not clear whether this is being meant in the official sense (i.e. ATLAS experiment), or in the unofficial sense (scientific experiment).

My read of the article is that "experiment" is used in the unofficial sense, but what is being tested is never made clear to the reader. Particles, perhaps? Um, ok. Whatever that means. Not sure what the hypothesis was, since I'm pretty sure particles exist and can be detected, so I'm confused.

I also still feel the article is unfocused as to these distinctions. By this I mean that the implicit context of the article (ATLAS experiment) appears to be what I would call "ATLAS program" or "ATLAS Collaboration". I would suggest either of those as a more appropriate title for the article. At that point, it would be clear that the context is the wider scope of the project. The detector could become a sub-section at that point. As the article currently stands, however, the context is muddled, and it switches back and forth between the project and the detector.

If I understand your argument correctly, you are saying that "ATLAS experiment" is the common jargon. I wouldn't know. I'm not a physicist. But if that is the case, then it is clearly an idiomatic usage of the word "experiment" which the article doesn't clarify. Since this appears to be the case for all the LHC collaborations/projects/whatever, it is probably worth explaining somewhere, whether it be just idiomatic, or something official. 96.40.48.159 (talk) 11:00, 4 October 2019 (UTC)

See the "physics program" section. ATLAS measures thousands of properties of particles and compares them with theoretical predictions. An experiment doesn't need to have a very narrow focus. There is no "ATLAS program". "ATLAS collaboration" can be used when it is about the people only. Detector and collaboration belong together. It makes no sense to discuss them in two separate articles. I'm a physicist, and in one of these big collaborations. --mfb (talk) 11:23, 4 October 2019 (UTC)

Hey, this has been a pretty productive exchange. I'd like to work with you further on improving this or other articles, if you are up for it. I could certainly point out a lot of confusing points in this article to begin with.

Getting back to what you just said, why not rename the article to ATLAS Collaboration, then? That reflects the scope accurately, without the confusing term experiment. — Preceding unsigned comment added by 96.40.48.159 (talk) 13:09, 4 October 2019 (UTC)

No, renaming the article would miss the point completely.

Ownership is a bit complicated but effectively irrelevant. Big changes are coordinated between the collaboration, the LHC team and CERN. --mfb (talk) 07:55, 5 October 2019 (UTC)

So now you're just going to dismiss my questions as meaningless? Guess I'm done here, then. — Preceding unsigned comment added by 96.40.48.159 (talk) 08:59, 5 October 2019 (UTC)

Findings

What has it found? Apart from a brief mention of the Higgs hidden away under "Experimental program," apparently nothing. But there's at least one other thing that I stumbled across just now, and presumably other stuff besides. It would be nice if some knowledgeable person could update the article. 79.64.186.66 (talk) 08:48, 6 December 2021 (UTC)

Hundreds of publications, but most of them never make it into secondary sources, and popular science reports about those that make it are usually bad. --mfb (talk) 07:03, 9 December 2021 (UTC)

Featured picture scheduled for POTD

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