Antimatter sticks around

Sep 22, 2011
The ALPHA Collaboration’s antihydrogen trap and detector. Antihydrogen is made when antiprotons (p) and anti-electrons (or positrons, e+) meet.  The octupole (not shown) and mirror magnetic coils confine the antihydrogen, and a silicon (Si) detector records matter-antimatter annihilation events. Credit: Ref. 1 © 2011 ALPHA Collaboration

By successfully confining atoms of antihydrogen for an unprecedented 1,000 seconds, an international team of researchers called the ALPHA Collaboration has taken a step towards resolving one of the grand challenges of modern physics: explaining why the Universe is made almost entirely of matter, when matter and antimatter are symmetric, with identical mass, spin and other properties. The achievement is remarkable because antimatter instantly disappears on contact with regular matter such that confining antimatter requires the use of exotic technology.

The collaboration of 39 researchers, including Daniel Miranda Silveira and Yasunori Yamazaki from the RIKEN Advanced Science Institute, Wako, trapped antihydrogen inside a ‘bottle’ defined by a set of magnetic fields created by an octupole magnetic coil and a pair of mirror coils (Fig. 1). The bottle could not confine antihydrogen unless they had extremely low energy, which represents a particular problem because is made through an extremely energetic process; and any cooling procedures must prevent antimatter and matter from meeting. In a previous ALPHA Collaboration experiment, the researchers succeeded in confining 38 antihydrogen atoms for at least one-fifth of a second.

Buoyed by their success, the collaboration focused on further cooling the antihydrogen atoms. Advances they made to two techniques proved especially fruitful. The first, evaporative cooling, relies on the fact that any collection of antiparticles will include some that are more energetic than others. By confining this collection inside an energy potential that lets only the most energetic particles escape, or evaporate, the entire collection can be effectively cooled, and can reach hundreds of degrees Celsius below freezing, Yamazaki explains. The second technique, autoresonant mixing, uses a technique called phase locking to mix the two constituents of antihydrogen—antiprotons and positrons—without warming the antiprotons. 

Once cooled in this way, the ALPHA Collaboration was able to trap more antimatter atoms, some for times exceeding 1,000 seconds. Critically, this is much longer than the time it takes for antimatter to relax to its lowest-energy, or ground, quantum mechanical state, which is a prerequisite for studying its properties with laser and microwave spectroscopic techniques. 

Trapping antimatter atoms in this way will allow physicists to address questions regarding the symmetry between matter and antimatter, which is currently understood to be a foundational property of physics, says Yamazaki. “If we see even a slight difference between hydrogen and properties, then the standard model of physics will need to be rewritten, and our understanding of the will change.”

Explore further: Beams come knocking on the LHC's door

More information: Andresen, G.B., et al. Confinement of antihydrogen for 1,000 seconds. Nature Physics 7, 558–564 (2011).

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User comments : 6

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SemiNerd
5 / 5 (3) Sep 22, 2011
I am still waiting to see if the anti-hydrogen is repelled by gravity or attracted by gravity. Last I heard that was still an open question.
rwinners
not rated yet Sep 22, 2011
Is the a symbiosis between the posi and anti elements? Do they annialate each other or do the become something else... or somewhere else?
StarGazer2011
3 / 5 (6) Sep 22, 2011
hmmm ... Higgs gone missing, anti matter bottled, CERN possibly observes FTL particles ... i smell new physics :)

But of course the science of climate change is settled and may not be questioned, ever.
El_Nose
5 / 5 (1) Sep 23, 2011
the Higgs has to have been found to go missing -- stricly speaking -- and i believe they are just now getting into the area that had the highest potential for the Higgs to be found ( could be wrong in that statement ... but i recall articles or maybe it was just a bloggers calculation that the Higgs might be closer to the 130-140 energy range.. i really don't remember ) -- but either way we will know if the Higgs exists by year end
StarGazer2011
3 / 5 (2) Sep 25, 2011
@El Nose: True, it hasnt gone missing, and yeah its still possible in the energy ranges left (not sure if they are the less or more likely band but either way). So yep, a year or so and we will know. Hopefully somoene will have either confirmed or explained the CERN FTL result by then also... exciting times
rodgod
not rated yet Sep 26, 2011
I know it sounds stupid, but I feel black holes are clumps of antimatter. Where else would you find the inexplicable goings on of the "holes"? Dark energy, Ha. The shock wave of matter and antimatter collusion ever pressing on the space/time around it causing the expansion of the universe, hmmmm?

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