Icon class icon_class fas fa-quote-left icon_class_computed fas fa-quote-left Related content An abstract Q(u)ark for M(u)ster M(u)ark Source Wikipedia Copyright information Text from Wikipedia and Wiktionary web pages quoted for educational purposes is subject to the Wikipedia Creative Commons Attribution ShareAlike Licence Snippet kind INFO Previous snippet A quark is a type of elementary particle and a fundamental constituent of matter. Full quote Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. URL https://en.wikipedia.org/wiki/Quark Next snippet Due to a phenomenon known as color confinement, quarks are never found in isolation; they can be found only within hadrons, which include baryons (such as protons and neutrons) and mesons, or in quark–gluon plasmas. Related snippets A quark is a type of elementary particle and a fundamental constituent of matter. Unlike leptons, quarks possess color charge, which causes them to engage in the strong interaction. The resulting attraction between different quarks causes the formation of composite particles known as hadrons Related snippets (backlinks) Due to a phenomenon known as color confinement, quarks are never found in isolation; they can be found only within hadrons, which include baryons (such as protons and neutrons) and mesons, or in quark–gluon plasmas. Quarks have various intrinsic properties, including electric charge, mass, color charge, and spin. Quarks ... are the only elementary particles in the Standard Model of particle physics to experience all four fundamental interactions, also known as fundamental forces (electromagnetism, gravitation, strong interaction, and weak interaction). Quarks ... are the only known particles whose electric charges are not integer multiples of the elementary charge. There are six types, known as flavors, of quarks: up, down, strange, charm, bottom, and top. Up and down quarks have the lowest masses of all quarks. The heavier quarks rapidly change into up and down quarks through a process of particle decay: the transformation from a higher mass state to a lower mass state. Because of this, up and down quarks are generally stable and the most common in the universe, whereas strange, charm, bottom, and top quarks can only be produced in high energy collisions (such as those involving cosmic rays and in particle accelerators). For every quark flavor there is a corresponding type of antiparticle, known as an antiquark, that differs from the quark only in that some of its properties (such as the electric charge) have equal magnitude but opposite sign. The Standard Model is the theoretical framework describing all the currently known elementary particles. This model contains six flavors of quarks (q), named up (u), down (d), strange (s), charm (c), bottom (b), and top (t). Antiparticles of quarks are called antiquarks, and are denoted by a bar over the symbol for the corresponding quark, such as ū for an up antiquark. Elementary fermions are grouped into three generations, each comprising two leptons and two quarks. The first generation includes up and down quarks, the second strange and charm quarks, and the third bottom and top quarks. Elementary fermions are grouped into three generations, each comprising two leptons and two quarks. The neutron is a subatomic particle, symbol n or n0, with no electric charge and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behave similarly within the nucleus, and each has a mass of approximately one atomic mass unit, they are both referred to as nucleons. A free neutron is unstable, decaying to a proton, electron and antineutrino with a mean lifetime of just under 15 minutes (881.5±1.5 s). This radioactive decay, known as beta decay, is possible because the mass of the neutron is slightly greater than the proton. The free proton is stable. Neutrons or protons bound in a nucleus can be stable or unstable, however, depending on the nuclide. Beta decay, in which neutrons decay to protons, or vice versa, is governed by the weak force, and it requires the emission or absorption of electrons and neutrinos, or their antiparticles. The free neutron has a mass of 939,565,413.3 eV/c2, or 1.674927471×10−27 kg, or 1.00866491588 u. The neutron has a mean square radius of about 0.8×10−15 m, or 0.8 fm, and it is a spin-½ fermion. The neutron has no measurable electric charge. With its positive electric charge, the proton is directly influenced by electric fields, whereas the neutron is unaffected by electric fields. The neutron has a magnetic moment, however, so the neutron is influenced by magnetic fields. The neutron's magnetic moment has a negative value, because its orientation is opposite to the neutron's spin. The neutron is classified as a hadron, because it is a composite particle made of quarks. The neutron is also classified as a baryon, because it is composed of three valence quarks. The finite size of the neutron and its magnetic moment both indicate that the neutron is a composite, rather than elementary, particle. A neutron contains two down quarks with charge −1⁄3 e and one up quark with charge +2⁄3 e. Visit also Visit also (backlinks) Flags
