Antiproton

Quark structure antiproton

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Photocopy of photograph (original print located in LBNL Photo Lab Collection). Photographer unknown. October 6, 1955. BEV-938. ANTI-PROTON SET-UP WITH WORK GROUP; E. SEGRE, C. HAER CAL,1-BERK,4-34.

Antiproton is the antiparticle or the antimatter counterpart of the proton. Antiprotons are denoted by the symbol \(\bar{p}\). Just like protons have a positive electric charge, antiprotons carry an equal but negative charge. In terms of mass, antiprotons share the same mass as their proton counterparts. The discovery of the antiproton was a significant milestone in the field of particle physics, providing crucial evidence for the existence of antimatter.

Discovery

The existence of the antiproton was theorized by physicists long before it was physically observed. The antiproton was discovered in 1955 by Emilio Segrè and Owen Chamberlain at the University of California, Berkeley's Bevatron accelerator. This discovery was groundbreaking and led to Segrè and Chamberlain being awarded the Nobel Prize in Physics in 1959.

Properties

Antiprotons possess several properties that mirror those of protons, albeit with opposite signs. These include:

- Charge: Antiprotons have a negative electric charge of -1 e (elementary charge), which is the exact opposite of the +1 e charge of protons. - Mass: The mass of an antiproton is equivalent to that of a proton, approximately \(1.67 \times 10^{-27}\) kilograms. - Spin: Like protons, antiprotons have a spin of 1/2, making them fermions.

When an antiproton comes into contact with a proton, the two particles annihilate each other, leading to the production of other particles and the release of energy, a process that is of great interest in the study of particle physics and antimatter.

Production

Antiprotons are produced in high-energy particle accelerators by colliding protons or other particles at high speeds. The energy from these collisions can create antiproton-proton pairs among other particles. These antiprotons can then be collected and stored for various experiments, including studies of antihydrogen and the fundamental symmetries of nature.

Applications

One of the most intriguing applications of antiprotons is in the field of medical therapy, specifically in the treatment of cancer through a method known as antiproton therapy. This approach seeks to utilize the high energy released during antiproton annihilation to target and destroy cancer cells with greater precision than conventional radiation therapy.

See Also

• Antimatter
• Proton
• Particle accelerator
• Particle physics