Proton



Proton

The quark structure of the proton.
Composition: 2 up, 1 down
Family: kg

938.272 029(80) MeV/c2

1.007 276 466 88(13) C
Spin: ½

In physics, the proton (Greek πρώτον / proton = first) is a electron.

Protons are spin-1/2 gluons.

Protons and allotrope).

Stability

Protons are observed to be stable and their theoretical minimum half-life is 1×1036 years. Grand unified theories generally predict that proton decay should take place, although experiments so far have only resulted in a lower limit of 1035 years for the proton's lifetime. In other words, proton decay has never been witnessed.

However, protons are known to transform into electron capture. This process does not occur spontaneously but only when energy is supplied. The equation is:

\mathrm{p}^+ + \mathrm{e}^- \rightarrow\mathrm{n} + {\nu}_e \,

where

p is a proton,
e is an electron,
n is a neutron, and
νe is an electron neutrino

The process is reversible: neutrons can convert back to protons through free neutron decays this way with a mean lifetime of about 15 minutes.

In physics and biochemistry

In physics and hydronium ion, which is considered a proton donating ion.

History

elementary particle.

See also: Prout's hypothesis

Prior to Rutherford, Eugene Goldstein had observed electron by J.J. Thomson, Goldstein suggested that since the atom is electrically neutral there must be a positively charged particle in the atom and tried to discover it. He used the "canal rays" observed to be moving against the electron flow in cathode ray tubes. After the electron had been removed from particles inside the cathode ray tube they became positively charged and moved towards the cathode. Most of the charged particles passed through the cathode, it being perforated, and produced a glow on the glass. At this point, Goldstein believed that he had discovered the proton.[3] When he calculated the ratio of charge to mass of this new particle (which in case of the electron was found to be the same for every gas that was used in the cathode ray tube) was found to be different when the gases used were changed. The reason was simple. What Goldstein assumed to be a proton was actually an ion. He gave up his work there. But promised that "he would return." However, he was widely ignored.

Antiproton

Main article: antiproton

The antiparticle of the proton is the antiproton. It was discovered in 1955 by Emilio Segrè and Owen Chamberlain, for which they were awarded the 1959 Nobel Prize in Physics.

CPT-symmetry puts strong constraints on the relative properties of particles and antiparticles and, therefore, is open to stringent tests. For example, the charges of the proton and antiproton must sum to exactly zero. This equality has been tested to one part in 108. The equality of their masses is also tested to better than one part in 108. By holding antiprotons in a Bohr magnetons, and is found to be equal and opposite to that of the proton.

High-energy physics

Due to their stability and large mass (compared to Earth's atmosphere. Such high-energy proton collisions are more complicated to study than electron collisions, due to the composite nature of the proton. Understanding the details of proton structure requires quantum chromodynamics.

See also

References

  1. ^ Weisstein, Eric (1996-2007). Proton -- from Eric Weisstein's World of Physics. Wolfram Research, Inc.. Retrieved on 2007-01-16.
  2. ^ Adair, Robert K.: "The Great Design: Particles, Fields, and Creation.", page 214. New York: Oxford University Press, 1989.
  3. ^ Gilreath, Esmarch S.: "Fundamental Concepts of Inorganic Chemistry.", page 5. New York: McGraw-Hill, 1958.


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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Proton". A list of authors is available in Wikipedia.