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Elementary particles are particles with no measurable internal structure; that is, it is unknown whether they are composed of other particles. [1] They are the fundamental objects of quantum field theory. Many families and sub-families of elementary particles exist. Elementary particles are classified according to their spin.
All observable subatomic particles have their electric charge an integer multiple of the elementary charge. The Standard Model's quarks have "non-integer" electric charges, namely, multiple of 1 / 3 e , but quarks (and other combinations with non-integer electric charge) cannot be isolated due to color confinement .
Among the 61 elementary particles embraced by the Standard Model number: electrons and other leptons, quarks, and the fundamental bosons. Subatomic particles such as protons or neutrons, which contain two or more elementary particles, are known as composite particles.
It has an electric charge of − + 1 / 3 e and a bare mass of 95 +9 −3 MeV/ c 2 . [ 1 ] Like all quarks , the strange quark is an elementary fermion with spin 1 / 2 , and experiences all four fundamental interactions : gravitation , electromagnetism , weak interactions , and strong interactions .
Having electric charge, mass, color charge, and flavor, quarks are the only known elementary particles that engage in all four fundamental interactions of contemporary physics: electromagnetism, gravitation, strong interaction, and weak interaction. [12]
Because the u and d quarks have similar masses, particles made of the same number of them also have similar masses. The exact u and d quark composition determines the charge, because u quarks carry charge + + 2 / 3 whereas d quarks carry charge − + 1 / 3 . For example, the three pions all have different charges π + = ( u d) π 0
Pages in category "Subatomic particles" The following 10 pages are in this category, out of 10 total. This list may not reflect recent changes.
The free neutron has a mass of 939 565 413.3 eV/c 2, or 939.565 4133 MeV/c 2. This mass is equal to 1.674 927 471 × 10 −27 kg, or 1.008 664 915 88 Da. [4] The neutron has a mean-square radius of about 0.8 × 10 −15 m, or 0.8 fm, [20] and it is a spin-½ fermion. [21] The neutron has no measurable electric charge.