kini mini
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From The Alchemist at ChemWeb.com (requires registration so I'll just copy & paste)
9 April 2003
Researchers at the cyclotron facility at Indiana University have observed the fusion of two nuclei of heavy hydrogen that formed the nucleus of helium and an uncharged pion, a subatomic particle.
Scientists say that the subatomic pion is one of the particles for the force that holds every nucleus together.
Science has searched for this process since the 1950s. The process happens when nature allows a "small violation" of what is known as charge symmetry. "If this symmetry violation had happened to be in the other direction, hydrogen would not have survived the Big Bang," says Edward Stephenson, physicist and the leader of the research team at Indiana University. He added, "and the universe would not have the hydrogen fuel that keeps stars shining, including our sun, making human life possible."
The main finding of the discovery is that "sometimes, large consequences hang on delicate balances in nature," says Stephenson.
According to the researchers, one key effect of the charge symmetry violation is that the neutron is slightly heavier than the proton, its charged partner. Accordingly, isolated neutrons decay into protons in about 10 minutes. And if the charge symmetry violation had been in the other direction and if the proton had been heavier than the neutron protons themselves would have decayed into neutrons. "Hydrogen could not have survived," says Stephenson.
Researchers employed the electron-cooled storage ring at the cyclotron laboratory to focus a beam of heavy hydrogen onto a target of the same material. The high precision of the beam enables researchers to employ just enough energy to make the uncharged pion without producing heavier particles, which are not needed. Detectors tracked the helium nuclei and captured the two photons particles of light that are created when the pions decay.
Researchers were said to have worked around the clock for two months, for, at the most, there were only five of these rare events each day, and the rate at which the rare fusion process occurs is expected to be a key piece of information in the ongoing research about charge symmetry.
The research was announced at the American Physical Society meeting in Philadelphia.
Gene J. Koprowski
9 April 2003
Researchers at the cyclotron facility at Indiana University have observed the fusion of two nuclei of heavy hydrogen that formed the nucleus of helium and an uncharged pion, a subatomic particle.
Scientists say that the subatomic pion is one of the particles for the force that holds every nucleus together.
Science has searched for this process since the 1950s. The process happens when nature allows a "small violation" of what is known as charge symmetry. "If this symmetry violation had happened to be in the other direction, hydrogen would not have survived the Big Bang," says Edward Stephenson, physicist and the leader of the research team at Indiana University. He added, "and the universe would not have the hydrogen fuel that keeps stars shining, including our sun, making human life possible."
The main finding of the discovery is that "sometimes, large consequences hang on delicate balances in nature," says Stephenson.
According to the researchers, one key effect of the charge symmetry violation is that the neutron is slightly heavier than the proton, its charged partner. Accordingly, isolated neutrons decay into protons in about 10 minutes. And if the charge symmetry violation had been in the other direction and if the proton had been heavier than the neutron protons themselves would have decayed into neutrons. "Hydrogen could not have survived," says Stephenson.
Researchers employed the electron-cooled storage ring at the cyclotron laboratory to focus a beam of heavy hydrogen onto a target of the same material. The high precision of the beam enables researchers to employ just enough energy to make the uncharged pion without producing heavier particles, which are not needed. Detectors tracked the helium nuclei and captured the two photons particles of light that are created when the pions decay.
Researchers were said to have worked around the clock for two months, for, at the most, there were only five of these rare events each day, and the rate at which the rare fusion process occurs is expected to be a key piece of information in the ongoing research about charge symmetry.
The research was announced at the American Physical Society meeting in Philadelphia.
Gene J. Koprowski