The down quark is a first-generation quark with a charge of -(1/3)e. It is the second-lightest of all quarks, with a bare mass of between 4 and 8 MeV. According to the Standard Model of particle physics, it and the up quark are the fundamental constituents of the nucleons; the proton contains one down quark and two up quarks, while the neutron contains two down quarks and one up quark. (Note that the majority of the mass in nucleons comes from the energy in the gluon field holding the quarks together, and not the quark masses themselves.) In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not made up of smaller particles. ... In particle physics, fermions, (named after Enrico Fermi), are particles with semi-integer spin. ... Quarks are one of the two basic constituents of matter in the Standard Model of particle physics. ... According to the standard model of particle physics, all the elementary particles seen in particle collision experiments can be divided into three generations. ... In particle physics, the mathematical combination of a particles energy and its momentum to give a value for the mass of the particle at rest. ... An electronvolt (symbol: eV) is the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt. ... The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness. In metric units, c is exactly 299,792,458 metres per second (1,079,252,848. ... The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ... The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ... In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is generated by the motion of its center of mass about an external point. ... Quarks are one of the two basic constituents of matter in the Standard Model of particle physics. ... The elementary charge (symbol e or sometimes q) is the electric charge carried by a single proton, or equivalently, the negative of the electric charge carried by a single electron. ... Mass is a property of a physical object that quantifies the amount of matter and energy it is equivalent to. ... An electronvolt (symbol: eV) is the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt. ... The Standard Model of Fundamental Particles and Interactions The Standard Model of particle physics is a theory which describes the strong, weak, and electromagnetic fundamental forces, as well as the fundamental particles that make up all matter. ... Particles explode from the collision point of two relativistic (100 GeV per nucleon) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ... The up quark is a first-generation quark with a charge of +(2/3)e. ... Nucleon is the common name used in nuclear chemistry to refer to a neutron or a proton, the components of an atoms nucleus. ... Properties [1][2] In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... This article or section does not cite its references or sources. ... In particle physics, gluons are vector gauge bosons that mediate strong color charge interactions of quarks in quantum chromodynamics (QCD). ... The magnitude of an electric field surrounding two equally charged (repelling) particles. ...

Down quarks were named when Gell-Mann and Zweig developed the quark model in 1964, and the first evidence for them was found in deep inelastic scattering experiments at SLAC in 1967. Murray Gell-Mann (born September 15, 1929) is an American physicist. ... George Zweig was originally trained as a particle physicist under Richard Feynman and later turned his attention to neurobiology. ... In physics, the quark model is a classification scheme for hadrons in terms of their valence quarks, ie, the quarks (and antiquarks) which give rise to the quantum numbers of the hadrons. ... 1964 (MCMLXIV) was a leap year starting on Wednesday (the link is to a full 1964 calendar). ... Deep Inelastic Scattering is the name given to a process used to probe the insides of hadrons (particularly the baryons, such as protons and neutrons), using electrons. ... The Stanford Linear Accelerator Center (SLAC) is a U.S. national laboratory operated by Stanford University for the U.S. Department of Energy. ... 1967 (MCMLXVII) was a common year starting on Sunday of the Gregorian calendar (the link is to a full 1967 calendar). ...

Hadrons containing down quarks

Some of the hadrons containing down quarks include: In particle physics, a hadron is a subatomic particle which experiences the strong nuclear force. ...

• Charged Pions (π^±) are mesons containing an up quark and an anti-down quark, or vice versa.
• The neutral pion (π⁰) is a linear combination of up-antiup and down-antidown, as are the ρ and ω mesons.
• The η and η' flavorless mesons are linear combinations of several quark-antiquark pairs, including down-antidown.
• A large number of detected baryons contain one or more down quarks. Like the nucleons, the Δ baryons are made of only up and down quarks: the Δ⁺ contains one down quark, the Δ⁰ contains two, and the Δ⁻ contains three.

In physics, a charge may refer to one of many different quantities, such as the electric charge in electromagnetism or the color charge in quantum chromodynamics. ... In particle physics, pion (short for pi meson) is the collective name for three subatomic particles: π0, π+ and π−. Pions are the lightest mesons and play an important role in explaining low-energy properties of the strong nuclear force. ... In particle physics, a meson is a strongly interacting boson, that is, it is a hadron with integral spin. ... The up quark is a first-generation quark with a charge of +(2/3)e. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interactions. ... In mathematics, linear combinations are a concept central to linear algebra and related fields of mathematics. ... Flavour (or flavor) is a quantum number of elementary particles related to their weak interactions. ... In mathematics, linear combinations are a concept central to linear algebra and related fields of mathematics. ... In particle physics, the baryons are a family of subatomic particles including the proton and the neutron (collectively called nucleons), as well as a number of unstable, heavier particles (called hyperons). ... In physics a nucleon is a collective name for the two baryons: the neutron and the proton. ...

See also

• Isospin