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Matter-Antimatter Bias Seen In Fermilab Collisions
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.
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.
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.
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.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Your expensive tube is doing fat lot of good, eh?! You go Fermilab! LHC can suck it!
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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
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.
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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.
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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".
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The real problem facing physicists right now is the lack of a Fermilab in Australia to confirm such a possibility.
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/
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.
which is totally what she said
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-)
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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.
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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".
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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.
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This is yet another reason why you shouldn't read mainstream media to get your physics news. Just reading the article summary makes me shiver all over.
Please, there are no fireballs at a particle collider and we are many many orders of magnitude in energy away from recreating the conditions after the Big Bang.
There is no miniature universe anywhere. Nothing went from being neutral to more matter than antimatter. Given that the (anti)matter in question here are (anti)muons
that would imply violation of charge conservation, which is not what they observed. This has nothing (well almost nothing, I'll explain in a sec) to do with why there is
so much more matter than antimatter in the universe, and the Standard Model does not suggest that there should be equal amounts either. The only correct
representation of facts in there is that the paper is indeed from the D0 collaboration and it has to do with seeing 1% more muons than antimuons.
Okay, so what did they do? They looked at decays of neutral B-mesons. These are curious mesons, because they oscillate back and forth between being a ..."), in this case direct evidence of new physics beyond the ...
B and an anti-B. If you ever took quantum mechanics: The propagating energy eigenstates are |B> +/ |anti-B> while |B> and |anti-B> are eigenstates of charge-conjugation+parity (CP).
The B can decay into a mu+ (antimuon) + other stuff, the anti-B can decay into a mu- (muon) + other stuff. (In both cases the other stuff has the opposite charge, so total
charge is conserved.) They saw a 1% asymmetry in the amount of mu+ vs. mu- which means that during the oscillation back and forth they end up 1% more often in one
than the other state which means there is a matter-anti-matter asymmetry in their behavior (technically there is CP violation in the mixing). The newsworthy fact is that in
the Standard Model this particular asymmetry (CP violation in mixing) is predicted to be about 25times smaller. With the uncertainties they quote that makes a 3-sigma discrepancy
which is regarded enough to claim "evidence of something" (you need 5 sigma to claim "observation of
Standard Model, which is what particle physicists have eagerly been looking for for the last decades. Personally, I'm holding my breath until I see the same measurement
from CDF (the other experiment at Fermilab). There have been many 3-sigma descrepancies in the past
As far as the universe is concerned, today we only have matter (forget about particle colliders, the point is there are no stars or huge clouds of anti-hydrogen out there).
As the theory goes after the Big Bang there were equal amounts of matter and antimatter, which would eventually have all annihilated into radiation and we wouldn't be here.
The matter we see today is from a tiny, 1 in 10^9, asymmetry in the amount of matter vs. anti-matter that was generated dynamically by particle reactions after the Big Bang.
When the universe cooled down and all the anti-matter got annihialted the tiny excess of matter was left over, which is the matter we see today. To generate this asymmetry one
needs (among other things) CP violation. There is CP violation in the Standard Model, it's just not nearly enough (several orders of magnitude) to generate the required asymmetry in the early
universe. It is totally not straightforward what the 1% asymmetry in the B-anti-B mixing from above translates into in the early universe, although I'm quite sure people are looking at
it right as I speak. I would be very surprised if it was enough though.