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LHC Research May Help Explain the Universe's Matter/Antimatter Imbalance

Soulskill posted about 2 years ago | from the level-up-your-sigma dept.

Space 113

suraj.sun sends this excerpt from the BBC: "Particles called D-mesons seem to decay slightly differently from their antiparticles, LHCb physicist Matthew Charles told the HCP 2011 meeting on Monday. The result may help explain why we see so much more matter than antimatter. The team stresses that further analysis will be needed to shore up the result. At the moment, they are claiming a statistical certainty of '3.5 sigma' — suggesting that there is less than a 0.05% chance that the result they see is down to chance. The team has nearly double the amount of data that they have analyzed so far, so time will tell whether the result reaches the 'five-sigma' level that qualifies it for a formal discovery."

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113 comments

More importantly.... (0)

Anonymous Coward | about 2 years ago | (#38104436)

Is such an imbalance dangerous for a universe this age? Does our universe need medical treatment?

Re:More importantly.... (3, Funny)

ackthpt (218170) | about 2 years ago | (#38104640)

Is such an imbalance dangerous for a universe this age? Does our universe need medical treatment?

Further, don't expect a balanced universe amendment any time soon.

Re:More importantly.... (5, Funny)

BergZ (1680594) | more than 2 years ago | (#38105460)

How many more galaxies must suffer before we build a universal healthcare system?!?

Re:More importantly.... (2)

GrpA (691294) | more than 2 years ago | (#38105036)

Any medical treatment given the universe would most certainly not be good for sub-microscopic lifeforms living on planets...

GrpA

First! (-1, Offtopic)

Zamphatta (1760346) | about 2 years ago | (#38104442)

Ha, never did that before

Re:First! (1)

bugs2squash (1132591) | about 2 years ago | (#38104512)

If you really want to contribute to the narrative, you should program one of your function keys to emit the string "Frosty Piss". You'll save valuable time when composing your groundbreaking first post.

Re:First! (0, Offtopic)

Zamphatta (1760346) | more than 2 years ago | (#38105082)

Man, a guy tries to fit in around here and he annoys people in just 31 characters. Wasn't like I wasted your time by writing a whole worthless paragraph and making you read for more than 2 seconds before moving on.

Re:First! (0)

Anonymous Coward | more than 2 years ago | (#38106144)

You're new here, aren't you?

Kaon decay (4, Informative)

tylersoze (789256) | about 2 years ago | (#38104446)

CP violation in weak interactions has been known for some time, specifically in neutral Kaon decay. If I'm understanding this results correctly, the surprise here seems to be the magnitude of the CP violation in this case.

Re:Kaon decay (5, Informative)

torako (532270) | about 2 years ago | (#38104538)

CP violation in Kaon decays can be explained by the Standard Model, but if the magnitude of CP violation they have claimed exists in the D system can not. It would be the first actual hint of physics beyond the Standard Model at the LHC. That would be some very exciting news (especially because everybody expected the big "discovery" detectors ATLAS and CMS to actually find something new first, i.e. the Higgs or Supersymmetry).

Careful: QCD hard! (5, Informative)

Roger W Moore (538166) | more than 2 years ago | (#38105150)

CP violation in Kaon decays can be explained by the Standard Model, but if the magnitude of CP violation they have claimed exists in the D system can not.

The calculations required to predict the amount of CP violation in meson systems are extremely hard to do. When I worked on the NA48 experiment, which measured direct CPV in the kaon system, the theorists were initially adamant that there was no way the parameter we measured (espilon-prime over epsilon) could be above 0.001 in the Standard Model. Several year later after both NA48 and KTeV had published results putting the parameter at well above that I saw a theory talk saying that these results were in perfect agreement with the Standard Model!

Now the discrepancy seems a lot larger here but, nevertheless, even if the result holds I'd give the theorists time to think about this and see whether they find problems in the calculations. I have a huge amount of respect for my theory colleagues but QCD calculations like this are fantastically hard so it is not at all uncommon for the results to change.

Re:Careful: QCD hard! (1)

Lawrence_Bird (67278) | more than 2 years ago | (#38108168)

Great comment and my semi-learned mind says you are likely to be proven correct. One other thing to point out - eventhough this is reported as 3.5sigma, that does not mean that additional statistics will push it to 5 and in fact, many 3 sigma-ish 'discoveries' end up being background or explained by other parameters/variables.

Re:Kaon decay (4, Funny)

Skarecrow77 (1714214) | more than 2 years ago | (#38105312)

I've spent too much time at encyclopedia dramatica recently, because I'm reading your statement way differently than I assume you mean it, based on my understanding of the meaning of the letters CP.

Re:Kaon decay (1)

Old Wolf (56093) | more than 2 years ago | (#38106580)

Didn't that shut down last year?

Re:Kaon decay (1)

Anonymous Coward | more than 2 years ago | (#38106658)

Nope! Everyone's favourite site still exists. Now at http://encyclopediadramatica.ch

What are the odds? (-1)

Anonymous Coward | about 2 years ago | (#38104464)

At the moment, they are claiming a statistical certainty of '3.5 sigma' â" suggesting that there is less than a 0.05% chance that the result they see is down to chance.

Seems legit. I mean how many times would one need to take the chance of the results being down to chance for that chance having a chance of happening?

Re:What are the odds? (0)

Anonymous Coward | about 2 years ago | (#38104520)

It means that out of 2000 parallel universes, this result will be true in 1999 of them. But as found out by Professor Murphy, we are likely to live in parallel world #2000.

Re:What are the odds? (1)

MurukeshM (1901690) | more than 2 years ago | (#38105688)

But as found out by Professor Murphy, we are likely to live in parallel world #2000.

What if the planet this result isn't true is #42?

Re:What are the odds? (3, Insightful)

ShakaUVM (157947) | more than 2 years ago | (#38104852)

>>>>At the moment, they are claiming a statistical certainty of '3.5 sigma' Ã" suggesting that there is less than a 0.05% chance that the result they see is down to chance.
>>Seems legit. I mean how many times would one need to take the chance of the results being down to chance for that chance having a chance of happening?

My plan for runs on the LHC is to run 1000 experiments and then pick the result that most supports some media-attention-grabbing theory that I'll just make up on the spot. /sacrasm off

In all honestly, a sigma of 0.05 isn't especially good for experiments like this. You don't have the confounding effects that make social "science" so hard to trust.

Re:What are the odds? (2)

Lawrence_Bird (67278) | more than 2 years ago | (#38108190)

I noted in a reply further up that 3sigma events many times end up going away as more statistics are taken. Google "3 sigma bump" for examples.

How do we know matter is more common? (2, Insightful)

Anonymous Coward | about 2 years ago | (#38104466)

A star made of antimatter would look exactly the same as one made of matter, wouldn't it? What if half of what we can see in the universe is antimatter?

Re:How do we know matter is more common? (0)

RobertLTux (260313) | about 2 years ago | (#38104596)

the problem is whenever matter and matching antimatter come in contact we get to see what E=MC^2 means (Very Large Bang for the TL;DR crowd). So an Anti-Star would most likely convert to a Black Hole before it could be seen.

Re:How do we know matter is more common? (1)

JonySuede (1908576) | more than 2 years ago | (#38105176)

do you get E=(anti+real)MC^2 or E=(anti*real)MC^2 when that happen ?

Re:How do we know matter is more common? (2)

CtownNighrider (1443513) | more than 2 years ago | (#38106164)

I believe it would be the sum of the masses. The anti matter is converted to energy plus the regular matter is converted to energy.

Re:How do we know matter is more common? (1)

JonySuede (1908576) | more than 2 years ago | (#38109654)

I tough so, but since my confusing quantum physic class (thought by a confused individual nonetheless) 10years ago, I almost don't have any certainties left about high energy physics....

Re:How do we know matter is more common? (4, Informative)

bsane (148894) | about 2 years ago | (#38104598)

The assumption is- if the universe had a fair amount of both, we'd see the gamma radiation leftovers from collisions, and we don't...

Re:How do we know matter is more common? (2)

ackthpt (218170) | about 2 years ago | (#38104678)

The assumption is- if the universe had a fair amount of both, we'd see the gamma radiation leftovers from collisions, and we don't...

May as well theorize the equal and opposite reaction to the Big Bang was one of Antimatter in an inverse universe. Not saying there's anti Cowboy Neal or anyone else in that universe, it's doing its own thing.

Re:How do we know matter is more common? (1)

nomel (244635) | about 2 years ago | (#38104738)

Could a stray bit of antimatter interacting with matter be the cause of some of the gamma-ray bursts?

Maybe something like a comet [wikipedia.org]?

Re:How do we know matter is more common? (2, Interesting)

Anonymous Coward | more than 2 years ago | (#38105748)

Posting anonymously because I've moderated in this discussion, but the quick answer is no, probably not - we know the signatures of matter/anti-matter annihilations very well, and they simply don't describe gamma ray bursts well enough.

Interestingly off-topic but I once entertained myself in an astronomy project filling in a cloudy night by calcuating if gamma ray bursts could possibly be accounted for by tightly-collimated electron/positron annihilations. My conclusion was that if they *weren't* collimated, it would involve almost as many electrons as seem likely to be in the universe, while if they were collimated it was possible... but you'd have issues with the red- or blue-shifting.

Now, I wouldn't actually *trust* those results since I did them in my second year of university, but they were interesting nonetheless. From people I'd actually trust who do this, it doesn't seem too likely that gamma ray bursts are caused by matter/anti-matter annihilations. But hell, it's physics, you never actually know.

Re:How do we know matter is more common? (2, Interesting)

Anonymous Coward | more than 2 years ago | (#38105170)

The assumption is- if the universe had a fair amount of both, we'd see the gamma radiation leftovers from collisions, and we don't...

That's not a great assumption. Contrary to popular belief, when random matter and antimatter collide, they don't always create gamma radiation. Anything is possible that still is consistent with a conservation of energy, momentum, and quantum number(s). Although the most likely result of a electron/positron collision is 2 gamma ray photons, it is not impossible that there is some other "light-weight" particle is formed (say like a neutrino/anti-neutrino or some unknown ligher particle or even whatever people might be calling dark matter that is not easily detectible). It may be that there is some unknown field/symmetry that favors the create of something else on the "lightweight" side instead of a photon. Or perhaps there is something that somehow segregates matter from antimatter (like dark energy with negative pressure) to prevent large scale production of gamma radiation.

However, the current wisdom is that antimatter just doesn't exist in large quantities in the universe because the cosmic radiation which is detected in our neck of the woods is mostly of matter origin (high energy protons, electron), and not of the anti-matter origin. If there were large amounts of anti-matter galaxies, and such, there probably wouldn't be this type of bias in cosmic radiation...

Re:How do we know matter is more common? (2)

Walt Dismal (534799) | more than 2 years ago | (#38105646)

I've never understood why the vacuum sea doesn't equally create as much anti-matter as it does matter. If it does, then why don't we observe constant energy bursts from collisions of antiparticles with normal particles? If doesn't, why would the vacuum sea be unsymmetrical? Either way, it doesn't seem to be reasonable.

Re:How do we know matter is more common? (1)

rpresser (610529) | more than 2 years ago | (#38106736)

Because a virtual particle pair is created at random from the sea, then annihilates resulting in a gamma, which then disappears into the sea without a trace.

Re:How do we know matter is more common? (1)

Walt Dismal (534799) | more than 2 years ago | (#38106960)

Wouldn't the gamma ray sometimes get absorbed by matter, perhaps imparting momentum. Would this maybe be akin to the force of 'dark matter', since it would provide a force 'out of nowhere' on normal matter. So maybe the universe is expanding because of the very nature of the vacuum sea, being rectified / non-symmetric in this way. Kind of delivering something out of nothing, not in a mystical way either.

Re:How do we know matter is more common? (1)

rpresser (610529) | more than 2 years ago | (#38108642)

Learning physics from Slashdot is not recommended. You sound generally interested in this material; go to the library and read some books that can actually explain it consistently.

Rude translation: I'm not going to figure this shit out for you. Go ask someone who not only knows but cares.

Re:How do we know matter is more common? (1)

Walt Dismal (534799) | more than 2 years ago | (#38109078)

I thank you for your wasted time replying. I am not trying to learn serious physics via Slashdot. Like anyone else using social media I'm merely looking for pointers, not a graduate seminar. Your candid and useless answer is appreciated in the spirit with which it was given, and in the same spirit, please investigate the effect of gravity on matter falling off bridges.

Really? (0)

Anonymous Coward | about 2 years ago | (#38104472)

I can't believe I saw this on Yahoo! before I saw it here on Slashdot. I also can't believe I still use Yahoo! either.

...the fuck? (0)

Moheeheeko (1682914) | about 2 years ago | (#38104478)

Dont article for the public on this kind of stuff need to be simplified for those of us not in the field? At least make the summary partly readable.

Re:...the fuck? (0)

Anonymous Coward | about 2 years ago | (#38104502)

Dont article for the public on this kind of stuff need to be simplified for those of us not in the field? At least make the summary partly readable.

This is already simplified...

Re:...the fuck? (0)

Anonymous Coward | about 2 years ago | (#38104542)

I'm a layman (artist of all careers) and even I can understand the summary.
Funny thing, /.'ers typically complain that the science articles are too dumbed down.

Work on your reading comprehension perhaps?

Re:...the fuck? (0)

Anonymous Coward | about 2 years ago | (#38104548)

Summary was great, if you knew anything about the LHC, five sigma, or particle physics in general, this wouldn't be an issue. Check out wikipedia and stop bitching.

Re:...the fuck? (0)

Anonymous Coward | about 2 years ago | (#38104552)

I'm not in the field, and I understood the entire summary.

Re:...the fuck? (2, Funny)

Anonymous Coward | more than 2 years ago | (#38104804)

Ok, here we go again:

LHCb sees where the antimatter's gone

ALICE looks at collisions of lead ions

CMS and ATLAS are two of a kind

They're looking for whatever new particles they can find.

The LHC accelerates the protons and the lead

And the things that it discovers will rock you in the head.

Re:...the fuck? (1)

Hank the Lion (47086) | more than 2 years ago | (#38108242)

Ok, here we go again:

LHCb sees where the antimatter's gone
ALICE looks at collisions of lead ions
CMS and ATLAS are two of a kind
They're looking for whatever new particles they can find
The LHC accelerates the protons and the lead
And the things that it discovers will rock you in the head.

Or, for the full version: http://www.youtube.com/watch?v=j50ZssEojtM [youtube.com]

Re:...the fuck? (1)

Surt (22457) | more than 2 years ago | (#38105128)

The universe we can see is primarily made up of matter. We know because there are characteristics of antimatter that would allow us to know if we were looking at an anti-galaxy, for example. But we don't know why there is so much matter, and not anti-matter, because the laws of physics we understand so far are neutral. So to explain the universe we see, there must be some rule we don't know about yet, which explains why the universe heavily favors matter.

This story is about a high-energy physics experiment which revealed a result which will help to explain the discrepancy if it can be confirmed. It will guide us towards that new rule to explain this particular mystery of the universe.

Observable universe (3, Interesting)

Lord Lode (1290856) | about 2 years ago | (#38104632)

What we see is just the observable universe. What if all this missing antimatter happens to be in a non-observable part? You'll never be able to see that! Unless those faster than light particles end the theory of observable universe of course.

Re:Observable universe (2)

bmuon (1814306) | more than 2 years ago | (#38104798)

And where would the unobservable universe be? Unless you're thinking about antimatter being coiled up in extra spatial dimensions, everything points to there being a process by which the symmetry is broken.

Re:Observable universe (1)

snowgirl (978879) | more than 2 years ago | (#38105112)

And where would the unobservable universe be? Unless you're thinking about antimatter being coiled up in extra spatial dimensions, everything points to there being a process by which the symmetry is broken.

To quote Wikipedia [wikipedia.org]

The current comoving distance to the particles which emitted the CMBR, representing the radius of the visible universe, is calculated to be about 14.0 billion parsecs (about 45.7 billion light years), while the current comoving distance to the edge of the observable universe is calculated to be 14.3 billion parsecs (about 46.6 billion light years),[1] about 2% larger.

I'm kind of surprised that you don't understand that the universe is larger than our observable universe.

Re:Observable universe (4, Interesting)

Surt (22457) | more than 2 years ago | (#38105148)

The unobservable universe is the infinite portion beyond the light speed horizon.
If you really want to be depressed, think about future civilizations in our galaxy for whom all other galaxies will have retreated beyond the light speed horizon. They will have a much harder time figuring out how the universe works.

Now realize that we may already be one of those future civilizations from the perspective of the lucky folks who got to see the universe early on.

Re:Observable universe (2)

Thing 1 (178996) | more than 2 years ago | (#38105268)

Similarly, the moon is receding from the Earth at a rate of 1.5 inches per year. At some point, it's going to "fly off into space". Imagine if we hadn't developed intelligence and telescopes until after that happened? We wouldn't be able to describe our origin!

I read a short story a while ago in which there were astronomers wondering at the significance of the six stars in their sky. As they were debating this, one of the stars winked out, and they were left with only five visible stars. Really neat thought experiment.

Re:Observable universe (1)

Surt (22457) | more than 2 years ago | (#38105380)

Well I have good news and bad news:
The good news is, we don't have to worry about ever losing the moon.
The bad news is that the reason will be the sun puffing up into a red giant, vaporizing both planets, long before the moon would be lost to us.

Re:Observable universe (0)

Anonymous Coward | more than 2 years ago | (#38106998)

Actually, the Moon would stay put in each case.

It's receding because it slowly siphons off Earth's rotational energy via tides. That energy goes into the Moon's orbital (potential) energy, which means the radius must increase.

At some point Earth too will be tidally-locked to the Moon and there's no more energy to steal. But then the Moon will always be above the same point on Earth, like a tourist attraction. "Come see the Leaning Tower of Pisa. And The Moon!"

Re:Observable universe (0)

Anonymous Coward | more than 2 years ago | (#38108084)

Wait.. Isn't the milky way going to collide with the Andromeda galaxy before that?

Re:Observable universe (1)

Surt (22457) | more than 2 years ago | (#38108958)

Yes, but there's no particular reason for that to destroy the earth, or otherwise disrupt the solar system. Galaxy collisions very rarely involve stars actually colliding.

Re:Observable universe (2)

Roger W Moore (538166) | more than 2 years ago | (#38105184)

And where would the unobservable universe be?

So far away that light from it has not yet had a chance to reach us, and thanks to the accelerating expansion, never will. I vaguely remember seeing some discussion of this in relation to inflation - we end up in a region which is matter dominated and another region is antimatter dominated with the two regions being causally separated by inflation.

However I believe that these theories have problems because you'd expect to be able to see gamma rays from the edges of each region...unless we happen to be strangely right in the centre of a massive matter-dominated region and cannot see the edge. Plus, since CP violation does exist it we do know that there is a matter/anti-matter asymmetry so it seems strange that, given this, there would be a completely unrelated mechanism to cause an imbalance.

Re:Observable universe (1)

Lord Lode (1290856) | more than 2 years ago | (#38107444)

> And where would the unobservable universe be?

Beyond the horizon where it is too far away for its information to ever reach us in our lifetime due to the lightspeed limit.

Re:Observable universe (0)

Anonymous Coward | more than 2 years ago | (#38105056)

Well, if it is not observable, it does not interact with our universe. Ant if it does not have any influence on it, it is completely IRRELEVANT. Forget about it.

Re:Observable universe (4, Interesting)

izomiac (815208) | more than 2 years ago | (#38105386)

As I understand it, the theory is that anything galaxy-sized or smaller must be almost completely composed of either matter or antimatter since otherwise it'd destroy itself. But, if you had antimatter galaxies then you'd expect to see gamma particles created when they interacted with matter galaxies.

That hasn't been observed, so the prevailing theory is that the whole universe is almost exclusively comprised of matter, thus there must be some preference in the laws of physics for matter. Personally, I suspect we'll discover an alternate explanation for the missing gamma rays that doesn't require an asymmetry in physics, such as your idea, but I'm certainly not an expert on the topic ("neophyte" would be generous).

Re:Observable universe (1)

Lord Lode (1290856) | more than 2 years ago | (#38109418)

We couldn't live in a universe with both matter and antimatter since they destroy each other. So it's obvious that a place where life appears and we get born to ask that question, has only one of them.

sigma? (0)

ThorGod (456163) | about 2 years ago | (#38104654)

Is this sigma terminology coming from some discipline? I've taken plenty of grad statistics and we've always called them alpha-significance levels.

From wikipedia:

The term Six Sigma originated from terminology associated with manufacturing, specifically terms associated with statistical modeling of manufacturing processes

So...the MBAs went and redefined some terms? And we're using them to summarize an empirical physics paper's results...why?

Re:sigma? (1)

EvanED (569694) | about 2 years ago | (#38104704)

s this sigma terminology coming from some discipline? I've taken plenty of grad statistics and we've always called them alpha-significance levels.

Surely if you've taken plenty of grad statistics, you've seen sigma used for the standard deviation.

They're saying something like the observed difference is 3.5 times sigma. That corresponds to an alpha=0.05% (or is it 99.95%?); they're not saying that sigma itself is 0.05%.

Re:sigma? (0)

Anonymous Coward | about 2 years ago | (#38104708)

5*sigma = 5 standard deviations.

Re:sigma? (5, Informative)

Anonymous Coward | about 2 years ago | (#38104742)

Re:sigma? (1)

John.P.Jones (601028) | more than 2 years ago | (#38105346)

They are averaging the results of many collisions, which are presumed to be independent and identically distributed of finite variance. Thus the central limit theorem dictates that the measured average is normally distributed about the mean of the true distribution of the statistics of a single collision. As they repeat the experiment n times the variance of the mean reduces at order n (hence std dev. the square root of the variance reduces at order sqrt(n)) Once they have repeated the experiment sufficient times the observed mean will be resolvable from a theoretical calculation (that is, if the theory is in error). They are waiting to verify that the expected (theoretical) result differs from the observed (measured average of many experiments) by at least six standard deviations (more experiments will lower the standard deviation while keeping the difference between theory and observation relatively static, or not). Then they will be certain that the theory is in error by however much they measure, then it is time to revise the theory to match the observation (without breaking any other observations and being able to predict new results that can be tested experimentally).

Re:sigma? (1)

hankwang (413283) | more than 2 years ago | (#38105022)

Funny that you mention alpha, since Wikipedia says: [slashdot.org] "In some fields, for example nuclear and particle physics, it is common to express statistical significance in units of the standard deviation Ïf of a normal distribution."

Re:sigma? (1)

FrootLoops (1817694) | more than 2 years ago | (#38106196)

units of the standard deviation Ïf of a normal distribution

Now how'd that get in there?

Re:sigma? (1)

MyLongNickName (822545) | more than 2 years ago | (#38105026)

How in the world do you take even ONE grad class and never hear of sigma or standard deviation? This is like the intro to the intro to statistics class and everything builds on it. You would have seen sigma dozens of times in each class...

Re:sigma? (2)

Theovon (109752) | more than 2 years ago | (#38105144)

Sounds like he had a brain-fart. RIgth now, he's smacking his forehead and calling himself an idiot because he didn't put together this sigma with the sigma he knows about as the standard deviation.

This sort of thing happens to me all the time. (Sometimes I feel really old.) I hate it when it makes me look stupid in front of someone. Like the day I was in the office of a Linguistics professor and asked a really stupid question about the fridge magnet letters that just happened to be IPA characters. I know IPA like the back of my hand, so I don't know what I was thinking.

I do other things that make me look stupider than I really am. Recently, I did a doozie in a slashdot comment. But this time, I was just being lazy. They were talking about Bulldozer, and I said a bunch of things that were wrong, mostly because I had forgotten, and I didn't take the time to look it up. I'm getting a Ph.D. specializing in computer architecture, but my lazyness made me look like a total idiot.

Fortunately, my dissertation committee won't be looking at my slashdot comments. :)

Re:sigma? (1)

ThorGod (456163) | more than 2 years ago | (#38105642)

Oh, I knew they were trying to refer to the second parameter of a normal distribution. But, whatever symbol we *use* for the variance (std dev) is just a symbol. We could call it: "a", "alpha", "sigma", "theta", all with various subscripts, and so on and so forth. Ever heard of six-theta_2 ? Six-theta_2 refers to 6 times the standard deviation of an estimated, normal curve. The term six-theta_2 only makes sense because we filled in the crucial parts (that shouldn't be left out).

Saying "sigma" without any qualifications leaves much to be assumed. I'm being persnickety about terms because the terminology lacked definiteness.

Re:sigma? (0)

Anonymous Coward | more than 2 years ago | (#38105794)

lol

given that it's standard terminology across the whole of high-energy physics, astronomy, cosmology, condensed matter physics, solid-state physics and for all i know laser physics, it's pretty acceptable terminology

quit this "OOOOH the second paramter of a normal distribution" shit. firstly, it's the second *moment* of a normal distribution. secondly, you only make yourself sound like a douche regardless.

Re:sigma? (1)

FrootLoops (1817694) | more than 2 years ago | (#38106248)

you only make yourself sound like a douche regardless.

Pot? I'd like to introduce you to Kettle. Oh, you say Kettle is black? Why yes, yes it is....

The second central moment is the variance, not the standard deviation.

Re:sigma? (0)

Anonymous Coward | more than 2 years ago | (#38106330)

"The second central moment is the variance, not the standard deviation."

Jesus fucking wept.

Re:sigma? (0)

Anonymous Coward | more than 2 years ago | (#38108770)

Oh yes, we will.

Re:sigma? (0)

Anonymous Coward | more than 2 years ago | (#38105106)

it means 99.95 percent.

http://www.wolframalpha.com/input/?i=integral+between+-3.5+and+3.5+of+1%2Fsqrt%282pi%29*exp%28-x^2%2F2%29

Re:sigma? (0)

Anonymous Coward | more than 2 years ago | (#38108004)

I've taken undergrad statistics and used sigma like they use all the time.

not an "explanation" (0)

dltaylor (7510) | about 2 years ago | (#38104750)

Identifying an a real-world mismatch of our models' predictions does not "explain" anything but that our models are incomplete.

When spheres, and spheres on spheres, don't explain planetary motion, let's try another model: the ellipse.

When "classical" mechanics can't explain why "orbiting" electrons don't fall into the nucleus of an atom due to electrostatic attraction, let's come up with a new model (while confusingly calling them "orbitals"): shells and quantum exclusion effects.

When whatever synthesis of strings and quantum gravity and pixie dust (or something very different from all of them) can provide a mathematical basis (that isn't all adjusted parameters) to describe this universe's preference for "matter" vs "anti-matter" (maybe the seventh harmonic of the property of "charge" in 12- (13- ?) dimensional space has a more-natural resonance with the fourth harmonic of the property "mass" for matter than for anti-matter, or something): we'll have a better model, but still, probably, not an "explanation".

This is Nobel material (0)

Anonymous Coward | about 2 years ago | (#38104784)

If they are able to demonstrate a symmetry breaking strong enough to explain the preponderance of matter in the universe then they are a very good bet for the Nobel price in physics.

a lot of mater in vicinity of experiment (1)

anwyn (266338) | more than 2 years ago | (#38104948)

All these experiments occured on earth in the vicinity of a lot of matter. How do we know that if we performed the experiments on a anti-earth we would not get an opposite result?

Re:a lot of mater in vicinity of experiment (0)

MyLongNickName (822545) | more than 2 years ago | (#38105048)

Because we did the experiment here, and these are the results we got. Feel free to doubt, but unless you are willing to create an experiment to falsify their findings, your claim has as much validity as young earth creationist.

Re:a lot of mater in vicinity of experiment (1)

osu-neko (2604) | more than 2 years ago | (#38105502)

All these experiments occured on earth in the vicinity of a lot of matter. How do we know that if we performed the experiments on a anti-earth we would not get an opposite result?

All these experiments occurred within 5000 years of 1AD. How do we know that if we performed the experiments before 5000 BC or after 5000 AD we would not get an opposite result?

The answer to both your question and mine is: we don't, but unless we have evidence that we would see an opposite result, it would be silly to believe we would in the absence of any good reason for it. Waving your hands and saying "maybe all the matter around influences things" is silly unless you have evidence to support that claim.

We don't "see" much more matter (1)

Hentes (2461350) | more than 2 years ago | (#38105340)

The radiation of an antimatter star would be the exact same as a matter star. There is no way of knowing that our visible Universe is mainly matter. That the Universe is made mostly of matter is a myth not really backed up.

Re:We don't "see" much more matter (4, Informative)

Surt (22457) | more than 2 years ago | (#38105422)

We know what annihilation looks like. If there were anti-stars in our galaxy, we'd see some substantial annihilation signatures in the mixing in nebulae for example. Even if whole galaxies were anit-matter, we'd see some signature where the galaxies mix. The smallest unit of mass that could be anti matter unnoticeably is probably the supercluster. Even then, doubtful that we couldn't see annihilation signatures along the great walls, for example.

Re:We don't "see" much more matter (0)

Anonymous Coward | more than 2 years ago | (#38105616)

We know what annihilation looks like.

We hope to see it in the upcoming debates.

--

And he shook hands with Dr. Edward Anti-Teller, and all that was left was gamma rays.

Re:We don't "see" much more matter (1)

Hentes (2461350) | more than 2 years ago | (#38107418)

We have good reason to believe that the Universe expanded from a much smaller initial state. Thus, the homogenous matter/antimatter regions that were created early could become very big, maybe bigger than our visible Universe. But even if not, galaxies very rarely collide, and even when they do, it's only a "collision" in a gravitational sense, it's very unlikely that two stars actually hit each other.

Re:We don't "see" much more matter (1)

Surt (22457) | more than 2 years ago | (#38107692)

Stars don't need to hit each other. The dust getting sucked into stars is plenty.

Re:We don't "see" much more matter (2)

Old Wolf (56093) | more than 2 years ago | (#38106562)

Firstly,it might not, as Nature respects neither C-symmetry (swapping matter for antimatter) nor CP-symmetry (swapping matter for antimatter and taking a reflection), as shown by TFA. So antimatter stars might behave differently or not even exist.

Secondly,if there were large amounts of antimatter in the observable universe, there would be huge amounts of radiation produced along the bounday between it and the bits that are made of matter. ('Empty space' isn't empty; look up Interstellar medium and Intergalactic medium).

This is the stupidest thing I've ever heard (0)

Anonymous Coward | more than 2 years ago | (#38105774)

Of course there's more matter than anti-matter. If there is a finite amount of matter/antimatter/energy then the only reason there is matter *at all* is that there is some imbalance. Otherwise it would all just be energy. There happens to be more matter than antimatter. Aren't you glad?

Re:This is the stupidest thing I've ever heard (1)

CtownNighrider (1443513) | more than 2 years ago | (#38106200)

The question is why. Physicists are still trying to figure out why at the creation of the universe there wasn't complete uniformity. This lack of uniformity also allowed galaxies to form, but just because something is good that doesn't mean it makes sense.

This is exciting (1)

trojjan (994851) | more than 2 years ago | (#38106408)

A bit off topic but this is very interesting find, just a few weeks after the 'Faster than light neutrinos'. Why can't we put money into projects like these instead of killing people in other countries. Err correction: Bringing democracy to other people.

Re:This is exciting (1)

Anonymous Coward | more than 2 years ago | (#38108254)

you need energy to run experiments

@Title (0)

Anonymous Coward | more than 2 years ago | (#38106868)

Unbelievable, the LHC is actually doing what it was (amongst other things) built for! Spread the news, SPREAD THE NEWS!!!!!

Significance (4, Informative)

kievit (303920) | more than 2 years ago | (#38107598)

Being a physicist myself I am very happy that this topic makes it into the news. But it is important to keep cool and skeptical. The statement that a statistical fluke has a probability of 0.05% implies that it is bound to happen if you let 2000 students do data analyses on independent data sets. There are indeed literally thousands of PhD students doing such analyses LHC data, trying to address hundreds of specific research questions that each require different data selections. So it is very likely that some of them will find a result several standard deviations away from the expectation. Actually 3.5 sigma deviations happen very often, because of all sorts of mistakes and inaccuracies in the analyses, but most of the time these mistakes are scrutinzed away before loud public announcements are made. After all scrutiny a few genuine statistical flukes should still remain, and recognized as such.

(For the xkcd inclined: green jellybeans linked to acne [xkcd.com].)

More caveats:

  • On slide 14 and 15 you see a summary of the estimated systematic errors and the final result: the deviation of the observed value from the expected value is 0.82 ± 0.21(stat.) ± 0.11(sys.) %. Estimating and combining systematic errors is almost by definition dark magic. It looks like the "3.5 sigma" was obtained by adding the statistical and systematic error in quadrature, which yields a total error of 0.237, and 0.82/0.237=3.5.
  • The statement that the probability of this 3.5 sigma deviation is 0.05% is based on the assumption that if you repeat this analysis several times on more data with exactly the same experimental setup, the deviations from expectation are distributed like a Gaussian (bell curve) with a sigma equal to the total error mentioned in the previous bullet point. That is a major idealization, it could be distributed in many other ways, and then the relation between the deviation (in units of sigma, which is also defined for non-Gaussian distributions) and "the fraction of events with such a deviations or larger" can be quite different. Furthermore, when repeating the identical experiment the systematical errors do *not* fluctuate (that is one of the aspects in which they differ from statistical errors), so aforementioned idealized Gaussian would have an arbitrary offset with a magnitude of the order of the estimated systematic error (0.11), in either direction, and a width of the actual statistical error, 0.21. Depending on what this systematic error really is, the true statistical significance is much larger or much smaller than the quoted 3.5 sigma.

So this is a very interesting result, but more study is needed and in my experience such flukes almost always evaporate in the light of more data and scrutiny. Still, it's not completely excluded that this was indeed the first hint of a real discovery (otherwise no researcher would ever do all that work).

OK, enough for now. Sorry for misinterpretations and other errors I might have made.

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