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Matter-Antimatter Bias Seen In Fermilab Collisions

kdawson posted more than 3 years ago | from the toe-of-god dept.

Science 304

ubermiester writes "The New York Times is reporting that scientists at Fermilab have found evidence of a very small (about 1%) average difference between the amount of matter/antimatter produced in a series of particle collisions. Quoting: '[T]he team, known as the DZero collaboration, found that the fireballs produced pairs of ... muons ... slightly more often than they produced pairs of anti-muons. So the miniature universe inside the accelerator went from being neutral to being about 1 percent more matter than antimatter.' This finding invites theorists to explain why there is so much more matter than antimatter in the universe, when the Standard Model suggests that there should be equal amounts of each." Here is the paper as submitted to Physical Review (PDF). The DZero team is looking forward to getting detailed data from the LHC once it ramps up operationally.

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304 comments

How has antimatter responded to this bias? (3, Funny)

valros (1741778) | more than 3 years ago | (#32249568)

Wasn't this the previously supposed hypothesis? That the big bang held a slight matter bias. Its great that we can recreate it now. Also, how has antimatter responded to this bias?

Re:How has antimatter responded to this bias? (5, Informative)

JoshuaZ (1134087) | more than 3 years ago | (#32249584)

That is a hypothesis used by cosmologists but it isn't part of the Standard Model. The Standard Model predicts particle behavior, not as much the macroscopic stuff. For most purposes the Standard Model agrees with the cosmological observations. This is one example where the Standard Model may be missing something or need tweaking.

Re:How has antimatter responded to this bias? (-1, Troll)

Anonymous Coward | more than 3 years ago | (#32250210)

This is one example where the Standard Model may be missing something or need tweaking.

Because good theories always make fundamental predictions that need to be contradicted by reality and then tweaked later in an ad-hoc fashion without ever revising their underlying principles. That's great science! Ah well, whatever gets you grants and funding right? In that case, status quo it is! We must always be openly hostile to all competing theories, refuse to publish them so they can be peer-reviewed, etc. That's progress.

Re:How has antimatter responded to this bias? (-1, Flamebait)

Anonymous Coward | more than 3 years ago | (#32250768)

We must downrate as troll anything that challenges our model!

Re:How has antimatter responded to this bias? (3, Funny)

Anonymous Coward | more than 3 years ago | (#32249586)

perhaps the "anti" in "antimatter" is dominate over the "identify matter" in "antimatter" and it sometimes acts as antiantimatter. so it isn't the universe giving a bias towards matter, it's antimatter being biased against itself.

Re:How has antimatter responded to this bias? (0)

Anonymous Coward | more than 3 years ago | (#32249964)

I think I just dislocated my brain..

Re:How has antimatter responded to this bias? (4, Funny)

DavidRawling (864446) | more than 3 years ago | (#32249588)

The antimatter is very upset at the bias, and is petitioning for full recognition and the payment of reparations.

Re:How has antimatter responded to this bias? (4, Funny)

francium de neobie (590783) | more than 3 years ago | (#32249642)

However, he died in a suicide bombing attack soon after he filed the petition, so the petition no longer matters.

Re:How has antimatter responded to this bias? (0)

Sehnsucht (17643) | more than 3 years ago | (#32249720)

As there were no next of kin, reparations defaulted back to the matter governing body.

Re:How has antimatter responded to this bias? (5, Funny)

somersault (912633) | more than 3 years ago | (#32250112)

That wasn't a suicide bombing, that was him trying to hug his girlfriend. While both their houses were alike in dignity, it turned out that their physical differences were too much for even love to overcome.

Re:How has antimatter responded to this bias? (0)

Anonymous Coward | more than 3 years ago | (#32250808)

...so the petition anti-matters.

FTFY

Re:How has antimatter responded to this bias? (3, Funny)

silentcoder (1241496) | more than 3 years ago | (#32249778)

>Also, how has antimatter responded to this bias?

Antimatter has declared the bias to be a clear-cut case of discrimination and has applied for status as a protected minority.

Re:How has antimatter responded to this bias? (5, Funny)

nacturation (646836) | more than 3 years ago | (#32249914)

Wasn't this the previously supposed hypothesis? That the big bang held a slight matter bias.

Slashdot has known this for more than a decade. After all, this isn't "news that anti-matters".

Sample Size? (1)

ScaryMonkey (886119) | more than 3 years ago | (#32249582)

How do they project statistics like that? I'm trying to imagine what kind of sample size you'd need to represent, well, everything in the universe.

Re:Sample Size? (5, Insightful)

Daniel Dvorkin (106857) | more than 3 years ago | (#32249604)

I'm trying to imagine what kind of sample size you'd need to represent, well, everything in the universe.

Sample size and significance calculations are generally done assuming an infinite population from which to sample, so "everything in the universe" is actually as close to perfect agreement between the math and the reality as you can get.

Is 1% significant? (5, Interesting)

gman003 (1693318) | more than 3 years ago | (#32249594)

For some experiments, 1% might be attributable to error. I've never done practical particle physics, though. Does this fall under experimental error, or is stuff like this usually re-creatable to seventeen decimal places?

I may not know much science, but I do know that margin of error is important.

Re:Is 1% significant? (1)

WarJolt (990309) | more than 3 years ago | (#32249648)

depends on the instruments used. 1% can be a lot with sensitive enough equipment.

Re:Is 1% significant? (5, Informative)

crescente (1334029) | more than 3 years ago | (#32249666)

Their error, as stated in the linked abstract, is less than 0.3%. So, if you believe they're doing statistics correctly, yes, the signal is greater than the noise. More importantly, even, say 1.0 - 0.3 = 0.7% is HUGE: the common estimate of matter-antimatter asymmetry at the big bang was merely a billion-and-one to a billion. (linky: http://livefromcern.web.cern.ch/livefromcern/antimatter/academy/AM-travel02c.html [web.cern.ch]). And that extra one in a billion is all the matter we have today.

Re:Is 1% significant? (0, Offtopic)

buchner.johannes (1139593) | more than 3 years ago | (#32250114)

Your post is nice, but I just wanted to say that that finding is huge! </Kayne West>
I hope they can reproduce the result elsewhere.

Re:Is 1% significant? (0)

Anonymous Coward | more than 3 years ago | (#32250148)

More importantly, even, say 1.0 - 0.3 = 0.7% is HUGE...

Seconded. I felt my jaw drop a little when they called 1% small. That the Standard Model implies a much lower fraction means that it is far, far from being complete.

This is big news. It's like saying that of boolean logic, 1 has a special property that 0 doesn't. All bits in nature are however qbits, so this research might provide further insights into quantum entaglement.

Re:Is 1% significant? (3, Informative)

FrangoAssado (561740) | more than 3 years ago | (#32249704)

Well, if they wrote a paper and submitted it to Phys Rev, you can rest assured they considered this (and it will be checked by many other physicists).

The abstract in the linked paper says the result they got differs by 3.2 standard deviations from the prediction given by the Standard Model. That's not conclusive, but it's significant. Surely they (or someone else) will keep looking in other data (from LHC, for example) to see if they can increase confidence.

Re:Is 1% significant? (5, Informative)

Trepidity (597) | more than 3 years ago | (#32249708)

Assuming that what the conclusion (p. 21) reports as "like-sign dimuon charge asymmetry of semileptonic b-hadron decays" is the number we're looking for, they do give a margin of error that's smaller than the asymmetry observed. They report the asymmetry as:

A = -0.00957 +/- 0.00251 (stat) +/- 0.00146 (syst)

I believe the two errors are there because they breaking out the statistical margin of error (due to sampling) and systemic margin of error (due to accuracy of apparatus and setup).

Re:Is 1% significant? (2, Informative)

tylersoze (789256) | more than 3 years ago | (#32249748)

Given the calculated ratio of photons to fermions during baryogensis the asymmetry is suppose to be even smaller than that, something like 1 extra particle of matter per 100 million if I remember correctly.

Re:Is 1% significant? (2, Informative)

Anonymous Coward | more than 3 years ago | (#32249784)

For some experiments, 1% might be attributable to error. I've never done practical particle physics, though. Does this fall under experimental error, or is stuff like this usually re-creatable to seventeen decimal places?

I may not know much science, but I do know that margin of error is important.

It's extremely significant given some models show that a 1% bias would account for the Universe as we know it. Dead even, no Universe. A 1% bias and we get our Universe. 1% may not seem like much but it's massive when you are talking about the origin of the Universe. As far as experimental error 1% is a pretty massive error in particle physics. Add a few zeroes, 0.0001%, and it'd still be interesting but a full 1% is pretty massive on the scale we are talking about.

Re:Is 1% significant? (1, Interesting)

Anonymous Coward | more than 3 years ago | (#32249998)

Makes you wonder what would a universe that swung the OTHER way look like? If there was a 1% bias towards antimatter, would we still have all the things our universe has? Would gravity still work the same way? What about magnetism? Man that blows my mind.

Re:Is 1% significant? (3, Informative)

FTWinston (1332785) | more than 3 years ago | (#32250838)

Makes you wonder what would a universe that swung the OTHER way look like?

Exactly the same. Gravity wouldn't be affected at all by a reversal of electrical charge. EM would be the same, but the other way around (not that we'd notice, as all our points of reference would be the other way around), and the strong and weak forces would still work just like you'd expect.

Re:Is 1% significant? (0)

Anonymous Coward | more than 3 years ago | (#32250096)

1% of a value extrapolated to approach infinity really can be an all or nothing difference.

Re:Is 1% significant? (0)

Anonymous Coward | more than 3 years ago | (#32249838)

It probably is. If they think it's worth a publication, they can most likely back it up statistically.
I've studied a physics myself for a few semesters and done experiments and about the first thing I learned at uni in physics in contrast to school physics was that error calculation was mandatory for analyzing experimental data and drawing conclusions. Actually it was the first chapter in my physics book, so my point is, it's safe to assume that those physicists know what they are doing. ^^

Re:Is 1% significant? (1)

ConfusedVorlon (657247) | more than 3 years ago | (#32249990)

Particle physicists deal almost entirely in probabilistic measurements, so they get pretty good at understanding their error bars.

1% could be enormous, or tiny depending on the sample size.

The fact that this has been published in Physical Review gives a strong implication that they have done and checked their sums.

LHC can suck it! (5, Funny)

oldhack (1037484) | more than 3 years ago | (#32249636)

Your expensive tube is doing fat lot of good, eh?! You go Fermilab! LHC can suck it!

Re:LHC can suck it! (0)

Anonymous Coward | more than 3 years ago | (#32250488)

Fermilab will antimatter when the LHC finally does come online in its full 14TeV power.

Re:LHC can suck it! (1, Informative)

Anonymous Coward | more than 3 years ago | (#32250644)

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I see anti-matter (0)

Anonymous Coward | more than 3 years ago | (#32249684)

It's obvious, the matter - anti-matter annihilated each other so the matter left in the universe is the 1% extra produced in the big bang. Of course, I have trouble calculating a tip so I'm probably out of my depth.

Budget (2, Interesting)

MichaelSmith (789609) | more than 3 years ago | (#32249706)

So presumably 99% of the mass-energy in the universe is currently energy, much of which must be potential and kinetic energy. The momentum of the Big Bang, the energy we will get back in the eventual collapse, light elements which will eventually fuse, and heavy elements which will eventually undergo fission.

Re:Budget (4, Funny)

ShakaUVM (157947) | more than 3 years ago | (#32249850)

>>The momentum of the Big Bang, the energy we will get back in the eventual collapse...

Eventual collapse?

Haven't kept up with physics, eh? =)

Re:Budget (2, Informative)

Trepidity (597) | more than 3 years ago | (#32250002)

As far as I can tell, the "big crunch" hypothesis isn't yet totally [arxiv.org] ruled out, though majority opinion is probably against it.

Re:Budget (1)

DMiax (915735) | more than 3 years ago | (#32250194)

Man, I wished so much for the collapse... It would mean that all the cool physics at high densities and small distances would happen again...

Re:Budget (1)

nadaou (535365) | more than 3 years ago | (#32250494)

never fear, opinions on the matter may swing back in favor of the big crunch at some time in the future. if you get my meaning.

Re:Budget (1, Interesting)

Graff (532189) | more than 3 years ago | (#32250544)

So presumably 99% of the mass-energy in the universe is currently energy, much of which must be potential and kinetic energy.

Not necessarily, it depends on how many iterations of annihilation-recombination took place.

For example, say we have 100% matter and antimatter, it interacts and annihilates leaving 1% matter. The remaining energy recombines back into matter and antimatter (through processes like vacuum fluctuation and virtual particles [wikipedia.org]), now 99% of that annihilates, leaving lasts iteration's 1% plus this iteration's 99% x 1% = 0.99% for a total of 1.99%. Next will be 98.01% x 1% = 0.9801%, and so on.

Thus the formula is:
0.99^0+0.99^1+0.99^2+...

This is a geometric series [wikipedia.org] and since r is 0.99 the limit is 1/(1-r) or 1/0.01 = 100%

So, theoretically, 100% of the energy could end up as matter. Of course in the real world not all of the energy combines into matter-antimatter pairs and not all of the matter and antimatter annihilate each other. This means that we end up with a universe where a good chunk of the original energy is matter, a tiny bit is antimatter, and the rest of it is energy of some sort. It's almost definitely not 99% energy, and it's almost definitely not 100% matter.

Re:Budget (1)

MichaelSmith (789609) | more than 3 years ago | (#32250696)

I wasn't sure about my assumption that the left over energy would be all our energy, including the energy which would be released ultimately fusing everything down to iron. But if that is the case we can't be 100% matter because then we would be at maximum entropy.

Uneven laws (4, Interesting)

Thanshin (1188877) | more than 3 years ago | (#32249750)

It would be so funny to discover now that the laws of physics are uneven in space...

That the same experiment gets you different results depending on which sid of the Milky Way you are...

Or they could be uneven in time. Maybe every 54.12 years the relation between produced matter/antimatter switches from 1:1.01 to 1.01:1.

Re:Uneven laws (5, Informative)

cc1984_ (1096355) | more than 3 years ago | (#32249808)

It would be so funny to discover now that the laws of physics ... be uneven in time. Maybe every 54.12 years the relation between produced matter/antimatter switches from 1:1.01 to 1.01:1.

You're not the first to think this (specifically the fundamental constants like the speed of light might be changing over time):

http://www.space.com/scienceastronomy/generalscience/constant_changing_010815.html [space.com]

Re:Uneven laws (5, Interesting)

silentcoder (1241496) | more than 3 years ago | (#32249814)

That would not be a "discovery" but a confirmation. Many physicists have suggested such hypothesis in the past. Even more have suggested asymetry in time -t that at various ages of the universe the fundamental constants may have been different to what they are now.

There are a few pieces of evidence suggesting this (the rate of decay of Oklo's uranium COULD be explained that way - though a natural fission reactor is a more plausible one), and several physicists have conjectured that the fine-structure-constant may have changed over time, and that would be an explanation for the wrong speed of galaxies that wouldn't require cold-dark-matter.

Our estimates on the age of the universe have changed 4 times in the past 2 decades - generally, it got younger with the current consensus at about 13-Billion years.
Of course if any of the fundamental constants had changed over time or in different regions of space - in the end, it's simply a matter of how you travel through space-time, then that means all bets are off. The fundamental constants determine the laws of physics. Thus far, outside of singularities like the big bang or black holes (and Stephen Hawking thinks we don't even need THOSE to be singularities) there is no really strong evidence for it. It's possible, but unlikely - and if true, means it's mathematically impossible for us to understand the universe.

Re:Uneven laws (4, Funny)

Anonymous Coward | more than 3 years ago | (#32249864)

So maybe Dragons really did exists once upon a time when the laws of physics were different.

Oh.. the creationists will love this.

Re:Uneven laws (0)

Anonymous Coward | more than 3 years ago | (#32250010)

Uhm... no, it's NOT possible. It's not possible for a CONSTANT to change ;) Then it wouldn't be a constant, and we could have to rename it.
( I know, I know, some computer languages have constants that can change...)

Re:Uneven laws (1, Interesting)

Anonymous Coward | more than 3 years ago | (#32250130)

Interesting idea. They may very well not be constants, but quasi-constant terms that simply change too slowly or too little for us to notice. The question is that they probably do not change in random ways, but in well defined patterns, so there could be more fundamental laws of physics awaiting to be discovered.

Re:Uneven laws (0)

Anonymous Coward | more than 3 years ago | (#32250822)

Pi can be viewed as changing over time.

Right on (1)

FreeUser (11483) | more than 3 years ago | (#32250354)

Uhm... no, it's NOT possible. It's not possible for a CONSTANT to change ;) Then it wouldn't be a constant, and we could have to rename it.

Exactly. Understanding our universe would involve deterimine what causes universal constants (universal variables?) to change over time. Assuming the change is not completely random (in which case, understanding our universe would become a great deal more difficult-though not necessarily impossible), a function over time or relationship to some other changing characteristic of the universe should emerge.

And no, it's not going to be some stupid Heinleinian "god made things old to fuck with us" kind of thing ... it will just mean the universe is far more interesting and magnifiscent that we (and most especially, more than the creationists) ever imagined.

Re:Uneven laws (0)

Anonymous Coward | more than 3 years ago | (#32250366)

Everybody knows that the universe only exists because the event horizon of two super-massive black holes are in contact with each other. http://xkcd.com/502/ [xkcd.com]

Re:Uneven laws (1)

SplashMyBandit (1543257) | more than 3 years ago | (#32250684)

Anyone can propose a theory. There is no shortage of speculative theories out there. Creating a theory is easy, even philosophers can do that. 'Proving' that the theory is not false the hard bit - something that sets the physicists apart from the philosophers. I'm not trying to bash philosophers here, since they have their place, merely trying to say that theories are pretty much 'dime a dozen' these days - but experimental verification of them is a much more rare and precious thing. That's why I stopped reading about all the whacky things the Universe could be doing - and concentrated on what is and isn't known about what it actually does do.

Re:Uneven laws (4, Interesting)

silentcoder (1241496) | more than 3 years ago | (#32250762)

Hypothesis are a dime a dozen, theories are supposed to be hypotheses that have stood the test of time for a while, but the terminology often gets mixed up to the detriment of science (even by scientists).

That said, in this case - the people who made these hypothesis are highly respected phycisists who had genuine puzzles they were attempting to explain. In most cases so far - there ended up being other more plausible explanations, but I just don't imagine serious physicists proposing an alteration to a fundamental constant lightly.

Right now there is some puzzles in cosmology that suggest that the fine structure constant may have been slightly lower in the past, there is further very strong evidence that supports the possibility (notably - the energy of the background cosmic radiation is slightly lower, by almost exactly the amount it would be if this was true).
BUT - and this is a big but, in the meantime, two other explanations for the cosmic radiation difference have been proposed. In both cases they don't rely on a different fine structure constant shortly after the big bang. But their supporting evidence is still being tested. In the meantime - neither explains the puzzles that led to the proposal in the first place, so if either is shown to be accurate - cosmology still can't answer those.
That puts the weight of evidence currently on the side of a change over time in the FSC, if only because it explains more observations than any other available hypotheses.
Downside - if the FSC was different, that means a LOT of other differences, because the FSC is an amalgamation of several other fundamental constants including Planck's. Change that in the past, and it means the physics of the early universe was slightly different to ours, and such a difference is a mathematical singularity, it's impossible from our side of it, to predict what was on the other side.

Re:Uneven laws (5, Interesting)

Black Gold Alchemist (1747136) | more than 3 years ago | (#32249846)

If the laws are uneven in time, that could lead to perpetual motion among other interesting consequences.

For example, pretend that the speed of light is variable over time and remember that E=mc^2. On earth, we build a matter-antimatter annihilation laser and point it at a base in space. When the speed of light speeds up to c=1.1 the normal value, we fire off the laser, converting 10 g of matter into 1.08749377 petajoules. The light energy travels for a time, during which the speed of light slows back down to c. It hits a set up in the space base that converts the light back into matter. We divide by normal c, and are left with 12.1 grams of matter. We mail it back to earth, and send 10 g grams back to the laser (to repeat the process). The other 2.1 g is used as starship fuel, worth over 180 terajoules. Don't rinse, but repeat.

Re:Uneven laws (3, Insightful)

Yvanhoe (564877) | more than 3 years ago | (#32250090)

Because, of course, magically, no doppler shift will happen when you elevate c to 110%...

Re:Uneven laws (1, Funny)

Anonymous Coward | more than 3 years ago | (#32250236)

Just tell Doppler to move out the way during the experiment, i'm sure he wouldn't mind.
God knows what he is doing up in space INSIDE the experiment chamber anyway. Sometimes i think that dude is getting a bit senile.

Re:Uneven laws (1)

leromarinvit (1462031) | more than 3 years ago | (#32250704)

If the laws are uneven in time, that could lead to perpetual motion among other interesting consequences.

Meh. All this proves is that the loss rate for interstellar mail must be at least 21%. It's not the postman's fault, it's a law of nature!

Re:Uneven laws (2, Interesting)

Joce640k (829181) | more than 3 years ago | (#32249862)

That would just mean that the "laws", aren't - in the same way that Newton's "laws" turned out to be not quite right when you're moving quickly.

And science would be cool about it. Excited about it, even.

Public imagination aside, scientists tend to celebrate when they're find out they were wrong (especially if it took big/expensive machines to do it...)

Re:Uneven laws (5, Funny)

Joshua Fan (1733100) | more than 3 years ago | (#32249924)

The real problem facing physicists right now is the lack of a Fermilab in Australia to confirm such a possibility.

new matter? (4, Interesting)

kix (24024) | more than 3 years ago | (#32249788)

I'm probably misunderstanding something here, but it seems that they have discovered that when the big bang happened, then because of this property, a bit more matter was created than anti-matter out of wherever they came in the first place, the rest of it annihilated with each other and everything else is made up from the "extra bits". This seems fairly reasonable.

Now, it is also known that new matter-antimatter element pairs are being created and annihilated all the time everywhere, this is where Hawking radiation comes from.

Does this new discovery mean, that it would be possible, that instead of an antimatter-matter pair a matter-matter pair is created sometimes instead and therefore the amount of matter in the universe is increasing (even if by a tiny amount)? Or are the conditions needed for this to happen too extreme to ever take place outside of big bangs and accelerators? Although as I understand some cosmic rays have far greater energies than accelerators.

Real physicists - please help me make sense of it all!

Re:new matter? (4, Informative)

chichilalescu (1647065) | more than 3 years ago | (#32250022)

no, this is doesn't fit the physics i know of.
in quantum field theory, you can describe the phenomena of a photon splitting into a particle-antiparticle pair that then anihilates to recreate the initial photon. these are the pairs that appear and disappear all the time (because of virtual photons that appear and disappear). However, a photon splitting into a particle-particle pair doesn't fit QFT.

Re:new matter? (3, Informative)

kix (24024) | more than 3 years ago | (#32250246)

Right, of course you are correct. After having read http://en.wikipedia.org/wiki/Virtual_particle [wikipedia.org] I actually understand that the question was rather silly. sorry about that. Although, if everyone read the correct wikipedia entries before asking things, there would be very few questions indeed ;)

thanks.

Re:new matter? (1)

stevelinton (4044) | more than 3 years ago | (#32250088)

Does this new discovery mean, that it would be possible, that instead of an antimatter-matter pair a matter-matter pair is created sometimes instead and therefore the amount of matter in the universe is increasing (even if by a tiny amount)? Or are the conditions needed for this to happen too extreme to ever take place outside of big bangs and accelerators? Although as I understand some cosmic rays have far greater energies than accelerators.

I think it's a bit more subtle than that -- things like a particle with a magnetic dipole decaying and tending to send the matter particle towards its North pole and the antimatter towards its South pole, but I'm not certain.

Re:new matter? (0)

Anonymous Coward | more than 3 years ago | (#32250106)

you mentioned Hawking radiation. i have been trying to educate myself about this but to no avail :) i am a psychologist. all i can remember is that the hawking radiation is made up of virtual particles; what are these virtual particles? are they as their names suggest "virtual"`? thx.

Re:new matter? (5, Funny)

MichaelSmith (789609) | more than 3 years ago | (#32250156)

Hawking radiation comes out of back holes. Because of quantum mechanics space is filled with virtual particles which come into existence and the annihilate themselves. Particles like an electron and an antielectron. Stuff like that. But if a black hole is nearby the electron could get swallowed, leaving the antielectron all alone in the world. The antielectron in this base becomes hawking radiation.

i am a psychologist

All right, okay. I should have read your post before I replied. How about this: particles come and go and nobody knows why. Sometimes they get lost which makes the other particles sad, so they wander off and get called "radiation".

Re:new matter? (0)

Anonymous Coward | more than 3 years ago | (#32250192)

sad particles. well just another indication that the incidence of depression among peers is greater than originally thought. thx. :)

Re:new matter? (1)

chichilalescu (1647065) | more than 3 years ago | (#32250632)

The uncertainty principle imposes that if you look at some region of space for very short time periods, the energy contained in that region of space is not well defined (it can have many values, with a minimum inversely proportional to the time interval). this energy must be associated (in quantum field theory, the model that must be used to describe the phenomena) to some field that satisfies certain constraints. for instance, it could be associated to a pairing of a particle and its antiparticle (or a pairing of two photons). these pairs are pairs of virtual particles, because they only exist for the small time interval, during which the unvertainty principle allows the existence of the corresponding energy (actually, it allows for an "error" in the amount of energy contained in the region of space).
So if you look at a region in space for some macroscopic time, you don't actually see anything, but as you start to look for smaller and smaller amounts of time, things start to happen (this was tested experimentally, see http://en.wikipedia.org/wiki/Casimir_effect [wikipedia.org]).
Hawking radiation is a very special occurence of this pair production. Supposedly, close to a black hole, it is possible that when a pair of virtual particles is created, one is eaten up by the black hole before they have a chance to anihilate one another, and the second particle manages to get away. At least, this is how I understand the idea, because I never had the chance to actually study it.

LHC can't contribute (3, Informative)

Bananenrepublik (49759) | more than 3 years ago | (#32249868)

LHC is a proton-proton collider, Tevatron (where D0 is situated) an antiproton-proton collider. Therefore Tevatron provides a situation which is symmetric between matter and antimatter, LHC doesn't. The conclusion of the paper is that there is a 1% excess of matter in a situation that started with no preference for matter or antimatter. I don't see how LHC could contribute to this given that they are always starting with two matter particles.

Re:LHC can't contribute (5, Informative)

Shillo (64681) | more than 3 years ago | (#32250284)

Had you read the abstract, you'd know that Fermilab's result is b+anti-b decay, not p+anti-p, so LHC is fine as long as they can specifically track which muons came from b quark decays.

As a matter of fact, they have a special detector just for that (it's not general-purpose, because b+anti-b pairs decay within centimetres from their creation point, so they actually drop particle tracker 5mm from the beam). See LHCb experiment.

Shit, don't let Al Sharpton hear this. (0)

Anonymous Coward | more than 3 years ago | (#32249872)

He'll be down here protesting about bias against the minority muon, and how this is a PLOT perpetrated by THE MAN, to keep a muon down.

They fight for survival (5, Interesting)

Laxator2 (973549) | more than 3 years ago | (#32249930)

The Tevatron is so thoroughly outclassed by the LHC that they have to take advantage of every opportunity to make a press release and show that they are still relevant. Once the LHC starts producing science data there will be impossible to justify funding for the Tevatron. The whole of Fermi Lab. (which uses about half the science money given by the D.O.E.) will be in danger of being closed, so they are fighting for survival. During the Bush administration they had to get private funding to avoid lay-offs. http://tierneylab.blogs.nytimes.com/2008/07/02/good-news-or-less-bad-news-for-american-science/ [nytimes.com]

Re:They fight for survival (2, Insightful)

DMiax (915735) | more than 3 years ago | (#32250228)

OTOH this is what happened to the LHC predecessor at CERN when Fermilab was bleeding edge. I suspect that in 20 years the #1 accelerator will be our fellow Americans' one. (unless they win the race to have short-sighted politicians...)

And I think it is probably better to have only one "best accelerator" at a time. LHC will be able to confirm the data from Tevatron *and* do something more. And so will do the next Tevatron with LHC data.

Re:They fight for survival (3, Interesting)

Laxator2 (973549) | more than 3 years ago | (#32250302)

Honestly, I don't know much about what happened at CERN before LHC, I only remember that they had LEP, which was an electron-positron collider, while the Tevatron is proton-anti-proton. The "scooping" of experiments happens all the time, for example Cornell's collider was the main place to study B mesons for about 20 years, before SLAC built the BaBar machine that accumulated in one year as much data as the Cornell machine has accumulated in 20 years. Luckily, the people at Cornell were able to move to K mesons (which contain strange quarks rather than bottom quarks) in a different energy range and do precision measurements. This way they kept the funding going. As for the next collider, the US Congress has canceled SSC back in 1993 and there is little chance such a project (40TeV, as opposed to LHC's 14TeV) will ever get built in US. http://en.wikipedia.org/wiki/Superconducting_Super_Collider [wikipedia.org]

Re:They fight for survival (1)

Thanshin (1188877) | more than 3 years ago | (#32250244)

I don't know anything about particle accelerators but...

It's a machine that does something that no other machines can do. So, I imagine there could be an industrial process that such machine could be used for.

Is there? Can the old accelerators be transformed from science labs into industrial tools?

Re:They fight for survival (1)

zmooc (33175) | more than 3 years ago | (#32250866)

Particle accelerators are all about the destruction of minute amounts of material. Industry is about construction of massive amounts of material. Therefore particle accelerators are the exact opposite of industry and I doubt an industrial application for particle accelerators can be made up.

Re:They fight for survival (1)

compro01 (777531) | more than 3 years ago | (#32250258)

In terms of raw energy levels, the LHC eats everyone's lunch, but the LHC does different work than the Tevatron. The LHC wouldn't be able to do any of the stuff they're doing in this instance, as the LHC doesn't deal with antimatter. It's a proton collider. the Tevatron is a proton-anti-proton collider.

Re:They fight for survival (0)

Anonymous Coward | more than 3 years ago | (#32250442)

Not true. Antimatter is produced in abundance at the LHC. When two protons collide, things get very messy, due to the marvels of QCD. A significant fraction of the LHC physics program is dealing with the properties of antimatter (and also oscillations/asymmetries between matter and antimatter).

Re:They fight for survival (1)

Hurricane78 (562437) | more than 3 years ago | (#32250532)

Of course to real scientists there is no point to NOT run both in parallel. There’s plenty of stuff the Tevatron can still do.
Oh, and maybe they should go big, and say that the US must be first again, and build a XLHC (extremely large hadron collider), crossing the whole country from coast to coast. ^^

Re:They fight for survival (1)

Jedi Alec (258881) | more than 3 years ago | (#32250778)

Hmmm....black hole in the middle of the Bible belt...

Hey, a man can dream right? And if *they* believe it maybe it will really happen? Think about it, we could call it the Rapture.

Maybe George W can solve this conundrum (1, Funny)

Anonymous Coward | more than 3 years ago | (#32249978)

"I'm somewhat out of my depth here," said Bush, a longtime Fermilab follower who describes himself as "something of an armchair physicist." "But it seems to me that, when reducing the perturbative uncertainty in the determination of Vub from semileptonic Beta decays, one must calculate the rate of Beta events with a standard dilepton invariant mass at a subleading order in the hybrid expansion. The Fermilab folks' error, as I see it, was omitting that easily overlooked mathematical transformation and, therefore, acquiring incorrectly re-summed logarithmic corrections for the b-quark mass. Obviously, such a miscalculation will result in a precision of less than 25 percent in predicting the resulting path of the tau lepton once the value for any given decaying tau neutrino is determined."

http://www.theonion.com/articles/bush-finds-error-in-fermilab-calculations,1463/

1% huh? (0)

Anonymous Coward | more than 3 years ago | (#32249984)

Shit, that's close enough for guvermint work, hoss! Let 'er rip!

PEAR (0)

Anonymous Coward | more than 3 years ago | (#32250006)

Maybe the experimenters believe in a bias towards matter, so they are actually reproducing the PEAR results.

http://www.princeton.edu/~pear/

Begs the question (0, Offtopic)

syousef (465911) | more than 3 years ago | (#32250086)

This finding invites theorists to explain

Aw, ubermiester, couldn't you have phrased that as "begs the question" so we could have 70 pedantic emails on the history and correct use of the term "begs the question" with pedants insisting that it is a logical fallacy and doesn't mean invites or asks the question?

Re:Begs the question (0)

Anonymous Coward | more than 3 years ago | (#32250676)

WTF you're complaining about lack of mistakes in the summary?

There's no pleasing you people!

Re:Begs the question (1)

Tim C (15259) | more than 3 years ago | (#32250718)

Never mind, console yourself with this pedantic reply pointing out that comments on slashdot are not emails instead.

Authors (1)

stevelinton (4044) | more than 3 years ago | (#32250100)

I know modern science is meant to be collaborative, but this paper has more than a page of authors! I note that they are listed alphabetically -- remind me to change my name to Aarons before taking up particle physics.

Re:Authors (2, Interesting)

mathfeel (937008) | more than 3 years ago | (#32250220)

I know modern science is meant to be collaborative, but this paper has more than a page of authors! I note that they are listed alphabetically -- remind me to change my name to Aarons before taking up particle physics.

This is typical of "big science" that involves tons of people like experimental high energy versus "bench science" or "desk science" like everyone else.

Re:Authors (0)

Anonymous Coward | more than 3 years ago | (#32250744)

I believe that in the ATLAS collaboration (one of the LHC experiments) the alphabetical surname to beat is "Aad".

All you need is love, love is all you need.. (0, Flamebait)

3seas (184403) | more than 3 years ago | (#32250110)

What makes the difference in this bias of what matters?

What other thing can beat out antimatter evil?

Just ask a Beatle. and a warm gun.

Dark matter, Dark energy, Anti-matter... What next? Anti-energy.

Anyone have any examples of Anti-energy?

Bzzzt! Contestant #3426345 rings in with... (5, Insightful)

IBitOBear (410965) | more than 3 years ago | (#32250128)

What is, "there used to be a lot more matter and antimatter before they started canceling each other out and now we live amongst the debris"?

or, from my safety fifth-grader...

What is "the standard model is wrong"?

And I don't mean that in a bad way. The "flat earth" hypothesis was an _amazing_ deduction at its inception. It was only off by eight inches declination for every mile. This was a _tiny_ margin of error. But error compounds and so does any other form of tiny, so eight inches per mile, an error of ~.0126% (e.g. 8/63360) was enough to make the earth round.

Ta dah! 8-)

Re:Bzzzt! Contestant #3426345 rings in with... (4, Informative)

queazocotal (915608) | more than 3 years ago | (#32250452)

It's been known for a long time that the standard model has problems.
To continue your analogy.

The earth is flat works really well as a model. If you're in a hilly terrain, you might suspect early on that the flat earth model isn't quite right.

To find out that earth is actually a slightly disorted sphere with a radius of some 6000km means that you have to go quite far (distance wise) to realise that the errors in the flat-earth model actually add up to a coherent alternative theory - a spherical earth.

It's much like this in physics.

Saying 'the standard model is wrong' - and giving plausible arguments - doesn't give much for alternative theorists to get their teeth into.

If however, you can produce a concrete measurement that can say 'The standard model is off by 0.3% here, 0.6% here, 1.2% here, and this looks _really_ like a curve of 0.5x+x^2 in the energy/bias ratio' - this can eliminate whole classes of alternate theories.

At the moment, string theory (and the descendant fields) suffer from an embarrasment of possibilities.
There are people arguing that the world is flat, round, toroidal, duck-shaped, ...

These theories are generally internally consistent, and can only be proved wrong with measurements of the real world. Without these measurements, the theories are interesting maths that you can make a career in maths about, but not predict the world in a useful way.

Re:Bzzzt! Contestant #3426345 rings in with... (2, Funny)

Hurricane78 (562437) | more than 3 years ago | (#32250546)

It's been known for a long time that the standard model has problems.

Well, of course. With them all being anorexic and on drugs, you can see their problems when looking at their bodies. ;)

how much space does one's spirit take up? (0)

Anonymous Coward | more than 3 years ago | (#32250348)

we already know how much it weighs? what is it's energy mark/potential? are there dark as well as light spirits? as one has never yet been captured or 're-created' in the lab, we'll just have to wait (hopefully for a while longer) to see?

the weight of a human spirit (3, Informative)

mangu (126918) | more than 3 years ago | (#32250576)

Yes, we do have an approximate idea of how much a human spirit weighs. The answer is 8e-23 g, or eighty trillionths of a trillionth of a gram.

This is calculated by estimating the average number of bits of information in a neuron and multiplying by the number of neurons in a brain. The energy needed for representing a bit of information is kT/6, where k is Boltzmann's constant (1.38e-23 J/K) and T is the absolute temperature of the medium which, in the case of a human brain, is nearly constant at 310 K.

Then energy is converted to mass according to the formula E=m*c**2, where E is the energy, m is the mass, and c is the speed of light in a vacuum.

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