• B-Mesons Provide Strong Evidence for Time-Reversal Asymmetry
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[quote=Phys.org](Phys.org)—Time marches relentlessly forward for you and me; watch a movie in reverse, and you'll quickly see something is amiss. But from the point of view of a single, isolated particle, the passage of time looks the same in either direction. For instance, a movie of two particles scattering off of each other would look just as sensible in reverse – a concept known as time reversal symmetry. Now the BaBar experiment at the Department of Energy's (DOE) SLAC National Accelerator Laboratory has made the first direct observation of a long-theorized exception to this rule. Digging through nearly 10 years of data from billions of particle collisions, researchers found that certain particle types change into one another much more often in one way than they do in the other, a violation of time reversal symmetry and confirmation that some subatomic processes have a preferred direction of time. Reported this week in the journal Physical Review Letters, the results are impressively robust, with a 1 in 10 tredecillion (1043) or 14-sigma level of certainty – far more than needed to declare a discovery. "It was exciting to design an experimental analysis that enabled us to observe, directly and unambiguously, the asymmetrical nature of time," said BaBar collaborator Fernando Martínez-Vidal, associate professor at the University of Valencia and member of the Instituto de Fisica Corpuscular (IFIC), who led the investigation. "This is a sophisticated analysis, the kind of experimental work that can only be done when an experiment is mature." BaBar, which collected data at SLAC from 1999 to 2008, was designed to tease out subtle differences in the behavior of matter and antimatter that might help account for the preponderance of matter in the universe. It produced almost 500 million pairs of particles called B mesons and their antimatter counterparts B-bar mesons for study. BaBar scientists found that B mesons and B-bar mesons do, indeed, behave differently in ways that violate so-called CP symmetry, which incorporates the symmetries of charge (positive versus negative) and parity (which can be thought of as left-handedness versus right-handedness). This discovery of CP violation contributed to the 2008 Nobel Prize in Physics. CP symmetry is linked with time reversal symmetry through the CPT (charge-parity-time) Theorem, which states that the three symmetries must remain in balance for any given particle system. If one of the symmetries is out of whack, at least one of the others must be, too. So the BaBar data, with its evidence of CP symmetry violation already in hand, was a good place to look for violation of time reversal symmetry that would serve to balance CPT as a whole. BaBar's new time violation analysis was based on a concept proposed in 1999. Researchers examined a chain of particle transformations in which B mesons flipped between two different states called B-zero and B-even. Taking advantage of the quantum entanglement of the B mesons, which enables information about the first decaying particle to be used to determine the state of its partner at the time of the decay, they were able to find that these transformations happened six times more often in one direction than the other. "This is a fresh way to understand data we had already used to measure CP violation," said BaBar physics coordinator Abner Soffer, associate professor at Tel Aviv University. "By looking at it slightly differently we were able to undeniably see time violation as well. What's nice is that the effect was there the whole time, but nobody had thought about it the right way before." Time violation had previously been seen in particles called neutral kaons by the CPLEAR experiment at CERN, but that measurement was not direct because of the inability to distinguish T violation from CP violation, and the interpretation of those results drew some criticism. It's hard to set up laboratory conditions that can see time reversal violation, Martínez-Vidal explained. But BaBar provided just the right conditions for a clear, direct measurement. "In the past, a true test of time reversal symmetry with unstable particles was considered to be impossible," said BaBar associate José Bernabéu, a professor at the University of Valencia and IFIC, and one of the originators of the analysis concept. "It's spectacular that the solution came from the same entanglement phenomenon used for quantum communication and computing." Michael Roney, BaBar spokesperson and professor at the University of Victoria in Canada, said "BaBar's data has been extremely fruitful and continues to produce important results, such as this unique and unambiguous test of quantum field theory. As we continue to work on almost 100 measurements from BaBar that investigate the fundamental nature of time and matter, we're gratified to have further validated this underlying theory."[/quote] [url]http://phys.org/news/2012-11-quantum-arrow-babar-asymmetry.html[/url] Here's the pre-print of the paper: [url]http://arxiv.org/abs/1207.5832[/url]
so two particles going in different directions from the point of view of another particle would look the same if they went forward or reverse wat
[QUOTE=Kai-ryuu;38528352]so going in reverse to a particle is the same as going forward wat[/QUOTE] No, it's not. That's the point of the experiment. Basically, it's been postulated that the laws of physics look essentially the same if you run them with time going backwards, but this is evidence that that's inaccurate.
[quote]"This is a fresh way to understand data we had already used to measure CP violation," said BaBar physics coordinator Abner Soffer, associate professor at Tel Aviv University. "By looking at it slightly differently we were able to undeniably see time violation as well. What's nice is that the effect was there the whole time, but nobody had thought about it the right way before." Time violation had previously been seen in particles called neutral kaons by the CPLEAR experiment at CERN, but that measurement was not direct because of the inability to distinguish T violation from CP violation, and the interpretation of those results drew some criticism. It's hard to set up laboratory conditions that can see time reversal violation, Martínez-Vidal explained. But BaBar provided just the right conditions for a clear, direct measurement.[/quote] This reminds me of when those two Swedish astronomers found the first planet through observing the Doppler effect caused by gravitational anomalies in stars, a bunch of other astronomers went back through their data and found a ton more planets that they hadn't realized they'd seen.
[QUOTE=Kai-ryuu;38528352]so going in reverse to a particle is the same as going forward wat[/QUOTE] Well, to a particle forward and backwards are probably the same thing; movement. Regardless, even though I don't really know exactly what this means, I assume this would have future applications.
[QUOTE=Phys.org]Now the BaBar experiment[/QUOTE] [IMG]http://www.kidscotv.tv/images/babar-271.jpg[/IMG]
[QUOTE=JohnnyMo1;38528326][url]http://phys.org/news/2012-11-quantum-arrow-babar-asymmetry.html[/url] Here's the pre-print of the paper: [url]http://arxiv.org/abs/1207.5832[/url][/QUOTE] Woah... This will have some deeply felt implications..
[QUOTE=Kai-ryuu;38528352]so two particles going in different directions from the point of view of another particle would look the same if they went forward or reverse wat[/QUOTE] Think about two passing particles. To the particle, either forwards or back, all that happens is that a particle is passed, so the time is symmetrical. The importance of this finding is that some kind of particle CANNOT work that way, and enforces the forward march of time.
[QUOTE=Bradyns;38528978]Woah... This will have some deeply felt implications..[/QUOTE] Such as?
[QUOTE=sambooo;38529050]Such as?[/QUOTE] Conclusively making time travel impossible.
[QUOTE=Hunt3r.j2;38529165]Conclusively making time travel impossible.[/QUOTE] Backwards, at least.
Traveling back in time would fuck with the law of entropy, and is thus impossible.
[QUOTE=Mr. Smartass;38529271]Backwards, at least.[/QUOTE] So, instead of that age old concept of "If we invent time travel, we'll travel back to this exact moment etc etc" we should have been saying "If we invent time travel we agree to travel to this exact moment in the future! With past cake and past hookers so we can have a sexy past future party in the present future." ...If you'll excuse me I have a thesis to write.
[QUOTE=V12US;38529332]Traveling back in time would fuck with the law of entropy, and is thus impossible.[/QUOTE] The law that is based on conclusions drawn from available evidence, no less. If contradictory evidence arises, the law would be proven false. That's how science happens.
[QUOTE=Hunt3r.j2;38529165]Conclusively making time travel impossible.[/QUOTE] I don't think so. I don't see how this invalidates the existence of closed timelike curves, since the curves are locally future-directed everywhere.
ITT: Astronuclear Time-Engineers By the way you all have no idea of what you're talking about.
[QUOTE=Zerohe;38530372]ITT: Astronuclear Time-Engineers By the way you all have no idea of what you're talking about.[/QUOTE] you get a wrench, because you're a tool anyhow this is pretty cool I guess, always fun to hear new developments in the world of physics.
[QUOTE=Zerohe;38530372]ITT: Astronuclear Time-Engineers By the way you all have no idea of what you're talking about.[/QUOTE] Yes, but layman speculation is fun.
[QUOTE=Zerohe;38530372]ITT: Astronuclear Time-Engineers By the way you all have no idea of what you're talking about.[/QUOTE] I'm not sure if you're aware of this, but they have these large buildings where you can go and people will tell you things about math science and stuff.
The more I read about physics the more bad puns I get in the chapter titles of parts of Half-Life.
[QUOTE=Zerohe;38530372]ITT: Astronuclear Time-Engineers By the way you all have no idea of what you're talking about.[/QUOTE] johnnymo1 studies physics at university if i'm not mistaken
[QUOTE=DainBramageStudios;38531101]johnnymo1 studies physics at university if i'm not mistaken[/QUOTE] Yes. And mathematics.
[QUOTE=Falubii;38531177]Yes. And mathematics.[/QUOTE] physics is just applied math
[QUOTE=Zerohe;38530372]ITT: Astronuclear Time-Engineers By the way you all have no idea of what you're talking about.[/QUOTE] I'm a physics and math student. aVoN is a physics grad. (Thought I haven't seen him around in a while) Like it or not there are some people here who do understand this.
[QUOTE=JohnnyMo1;38532191]I'm a physics and math student. aVoN is a physics grad. (Thought I haven't seen him around in a while) Like it or not there are some people here who do understand this.[/QUOTE] 1. You 2. ? Alright, comprehensive list. Don't get me wrong, I enjoy the discussion of physics and scientific discoveries wholeheartedly. Physics is my favourite science (fuck biologists) and next year I hope to be enrolled in an engineering program. However -- and I hope I will be agreed with by some on this -- a seemingly unavoidable singularity of ANY THREAD involving a new discovery within physics results in the pseudo-debation of fucking time travel. "YES, THAT IS EXACTLY IT, TIME TRAVEL IS DEFINITELY POSSIBLE BECAUSE OF THIS" "NO, YOU ARE WRONG, TIME TRAVEL IS IMPOSSIBLE AND WILL NEVER HAPPEN" Then shit like "CAUSALITY LOOPS" gets brought up when, in reality, the only thing looping is their titsucking gobs.
[QUOTE=Zerohe;38532477]1. You 2. ? Alright, comprehensive list. Don't get me wrong, I enjoy the discussion of physics and scientific discoveries wholeheartedly. Physics is my favourite science (fuck biologists) and next year I hope to be enrolled in an engineering program. However -- and I hope I will be agreed with by some on this -- a seemingly unavoidable singularity of ANY THREAD involving a new discovery within physics results in the pseudo-debation of fucking time travel. "YES, THAT IS EXACTLY IT, TIME TRAVEL IS DEFINITELY POSSIBLE BECAUSE OF THIS" "NO, YOU ARE WRONG, TIME TRAVEL IS IMPOSSIBLE AND WILL NEVER HAPPEN" Then shit like "CAUSALITY LOOPS" gets brought up when, in reality, the only thing looping is their titsucking gobs.[/QUOTE] But this thread has time in the title.
[QUOTE=Zerohe;38532477]I don't understand what anyone's talking about, they must just be making stuff up.[/QUOTE]
[QUOTE=Zerohe;38532477]1. You 2. ? Alright, comprehensive list. Don't get me wrong, I enjoy the discussion of physics and scientific discoveries wholeheartedly. Physics is my favourite science (fuck biologists) and next year I hope to be enrolled in an engineering program. However -- and I hope I will be agreed with by some on this -- a seemingly unavoidable singularity of ANY THREAD involving a new discovery within physics results in the pseudo-debation of fucking time travel. "YES, THAT IS EXACTLY IT, TIME TRAVEL IS DEFINITELY POSSIBLE BECAUSE OF THIS" "NO, YOU ARE WRONG, TIME TRAVEL IS IMPOSSIBLE AND WILL NEVER HAPPEN" Then shit like "CAUSALITY LOOPS" gets brought up when, in reality, the only thing looping is their titsucking gobs.[/QUOTE] wow dude you have a lot of fucking dedication to argue this needless and insulting point that more or less means nothing
[QUOTE=Zerohe;38532477]1. You 2. ? Alright, comprehensive list. Don't get me wrong, I enjoy the discussion of physics and scientific discoveries wholeheartedly. Physics is my favourite science (fuck biologists) and next year I hope to be enrolled in an engineering program. However -- and I hope I will be agreed with by some on this -- a seemingly unavoidable singularity of ANY THREAD involving a new discovery within physics results in the pseudo-debation of fucking time travel. "YES, THAT IS EXACTLY IT, TIME TRAVEL IS DEFINITELY POSSIBLE BECAUSE OF THIS" "NO, YOU ARE WRONG, TIME TRAVEL IS IMPOSSIBLE AND WILL NEVER HAPPEN" Then shit like "CAUSALITY LOOPS" gets brought up when, in reality, the only thing looping is their titsucking gobs.[/QUOTE] this is why physicists don't tend to get laid
[QUOTE=Zerohe;38530372]ITT: Astronuclear Time-Engineers By the way you all have no idea of what you're talking about.[/QUOTE] As an engineer I can tell you this is more in the realm of theoretical Physics (they aren't that separate though). Which at least one, but probably more, in this thread studies. Actually not theoretical, since they conducted an experiment on it.
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