Wednesday, May 04, 2011
In an experiment at CERN, anti-electrons (positrons) were mixed with anti-protons. They combined, the positrons apparently reaching a ground state. A positron bound to an anti-proton is an atom of anti-hydrogen.
Normal hydrogen consists of an electron bound to a proton. The energy levels and properties of hydrogen have been well-studied.
Anti-hydrogen consists of an anti-electron bound to an anti-proton. The properties of anti-hydrogen are not well known, and are very, very interesting to study.
Anti-hydrogen has been created before, but what makes this experiment at CERN special is that 308 anti-hydrogen atoms were collected (about ten times more than any previous result) and the anti-hydrogen lived for 1000 seconds or almost 17 minutes, about 10,000 times longer than previous results.
This quantity and longevity of anti-hydrogen makes possible detailed studies of the properties of anti-matter atoms.
Our universe seems to consist mostly of matter, with anti-matter created only transiently in collisions between particles at high energy. Anti-matter is believed to be very similar to matter except for the reverse of certain specific properties, notably charge: for example, an anti-proton is expected to have the same mass as a proton, but be negatively charged. A positron is expected to have the same mass as an electron, but with positive charge. Anti-matter particles are expected to behave the same as matter particles under the influence of gravity. The energy levels of an anti-hydrogen atom are expected to be calculable using known methods for calculating energy levels of atoms.
All these "expected's" need to be tested. This new experimental result makes these tests begin to be feasible.
Here is an article about this result:
Here is the original pre-print:
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