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Encyclopedia > Decay mode

In physics, the decay mode describes a particular way a particle decays. Since antiquity, people have tried to understand the behavior of matter: why unsupported objects drop to the ground, why different materials have different properties, and so forth. ...


For radioactive decay (the decay of nuclides) the decay modes are: Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles (radiation). ... ...

Typically one decay mode predominates for a particular nuclide. Branching ratios are used when this is not true. Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle and transforms into a nucleus with mass number 4 less and atomic number 2 less. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... Antineutrinos, the antiparticles of neutrinos, are neutral particles produced in nuclear beta decay. ... Positron emission is a type of beta decay, sometimes referred to as beta plus (β+). In beta plus decay, a proton is converted to a neutron via the weak nuclear force and a beta plus particle (a positron) and a neutrino are emitted. ... The neutrino is an elementary particle. ... Electron capture is a decay mode for chemical elements that will occur when there are too many protons in the nucleus of an atom, and there isnt enough energy to emit a positron; however, it continues to be a viable decay mode for radioactive elements that can decay by... In the process of beta decay unstable nuclei decay by converting a neutron in the nucleus to a proton and emitting an electron and anti-neutrino. ... Proton emission (also known as proton radioactivity) is a type of radioactive decay in which a proton is ejected from a nucleus. ... Neutron emission is a type of radioactive decay in which an atom contains excess neutrons and a neutron is simply ejected from the nucleus. ... Cluster decay is the nuclear process in which a radioactive atom emits a cluster of neutrons and protons. ... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... This is a technical term in particle physics and nuclear physics. ...


A decay will sometimes leave the nucleus in an excited state. When long lived these states are called isomers. These isomers will typically decay to the ground state of the nuclide, but unlike the radioactive decays above these isomeric transitions do not change one nuclide into others. These decays are: In quantum mechanics, an excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum). ... Isomeric states are the long-lived excited states of a nuclide (also called the metastable states). ...

  • Emission of a high-energy photon (gamma emission)
  • Ionizing the atom (internal conversion)

  Results from FactBites:
 
Physics News Graphics: Newly Identified Top-Quark Decay Modes (566 words)
In the "all-hadronic" decay mode, pictured above, each W boson decays into a pair of quarks, for a total of four quarks (q1, q2, q3, q4).
(2) A rare decay mode is the "dilepton mode" in which each W particle decays into a lepton (such as an electron or muon) plus a neutrino.
The first identified decay mode for the top quark when it was discovered back in 1995, the lepton-plus-jets mode is the basis of a new, record-high-accuracy top mass determination from the D0 experimental group at Fermi National Accelerator Laboratory (S. Abachi et al., Physical Review Letters, 18 August).
Grand Unification Balls of Light Decay Modes (822 words)
This decay mode is very common in particles that are almost completely harmonic, such as the cores of spherical galaxies and stars.
A distinguishing feature of this decay mode is that the original asymmetries were spread out enough not to allow them to combine along the equator and create a "split" decay.
This decay mode has an electromagnetic field that spins around the equator of the ball-of-light that gives a spinning motion to the ball-of-light and gives a spiral shape to the ejecta.
  More results at FactBites »

 
 

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