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hue

(4,949 posts)
Wed Apr 24, 2013, 04:24 PM Apr 2013

What's the Matter with Antimatter in the Atom Smasher?

http://www.livescience.com/29009-antimatter-matter-atom-smasher.html

Matter and antimatter particles are behaving differently inside a giant atom smasher in Switzerland, physicists announced today (April 24). The discovery could help solve the riddle of why the universe is made of matter and not its strange sibling, antimatter.

All matter particles are thought to have antimatter counterparts with the same mass but opposite charge and spin. When the universe sprang into being 13.8 billion years ago with the Big Bang, it probably had similar amounts of matter and antimatter. Most of this antimatter is thought to have been destroyed in collisions with matter (when the two meet, they annihilate each other), and all that's left over in the universe today is a small overabundance of matter.

To understand why matter dominated over antimatter, physicists look for any differences in how the two behave that might explain the discrepancy. These differences are called charge-parity violation (CP violation), and that's just what scientists have found inside the Large Hadron Collider (LHC) in Geneva. [Whoa! The Coolest Little Particles in Nature]

Inside the 17-mile-long (27 kilometers) underground ring of the machine, protons speed up and smash into each other, creating a shower of daughter particles. One experiment at the collider called LHCb (it stands for "LHC beauty&quot studies these daughter particles for signs of CP violation that might help elucidate the nature of antimatter.

After analyzing about 70 trillion proton-proton collisions, LHCb found that a particle called the B_s meson was created slightly more often in its matter form than in its antimatter counterpart. B_s (pronounced ("B-sub-S&quot mesons are made of bottom quarks and strange anti-quarks, whereas antimatter B_s mesons have an antimatter bottom quark and a matter strange quark ("bottom" and "strange" are two flavors of quarks, and anti-quarks are the antimatter partner particles of normal matter quarks).
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What's the Matter with Antimatter in the Atom Smasher? (Original Post) hue Apr 2013 OP
Yeah, that's exactly the sort of asymmetrical weirdness I think they've been looking for for a while Warren DeMontague Apr 2013 #1
Thanks for this post. byronius Apr 2013 #2
The neutral Kaon has been known to violate CP symmetry since 1964... DreamGypsy Apr 2013 #3

Warren DeMontague

(80,708 posts)
1. Yeah, that's exactly the sort of asymmetrical weirdness I think they've been looking for for a while
Wed Apr 24, 2013, 04:25 PM
Apr 2013

Cool.

DreamGypsy

(2,252 posts)
3. The neutral Kaon has been known to violate CP symmetry since 1964...
Thu Apr 25, 2013, 08:14 PM
Apr 2013

... and has been recognized as a source of differences in abundance of matter/antimatter in the universe for quite a while. The article mentions that

CP violation was first discovered in neutral particles called kaons at the Brookhaven National Laboratory in Long Island in the 1960s. It took 40 more years for researchers in the United States and Japan to find the next example of this asymmetry in the B0 meson. After that, the LHCb experiment and others found evidence for CP violation in the B+ meson.


So we now know about K0 (the '0' should appear as an superscript), B+, and now these LHCB results give us Bs (subscript 's') as give clues to abundance of matter.

Yet these instances of CP violation aren't enough to explain the prevalence of matter over antimatter in the universe.

"We still have a lot to do to understand the real nature of antimatter," Shears said. "We know we don't understand the whole story. We've just filled in a little bit more information — a block in our jigsaw puzzle if you like."


I tried to find the associated paper in Physical Review Letters earlier today and didn't. I'll look again later.

Thanks for the post, hue.
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