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Antineutrinos, decay

Pauli proposed that two particles were emitted, and Fermi called the second one a neutrino, V. The complete process therefore is n — p -H e 9. Owing to the low probabiHty of its interacting with other particles, the neutrino was not observed until 1959. Before the j3 -decay takes place there are no free leptons, so the conservation of leptons requires that there be a net of 2ero leptons afterward. Therefore, the associated neutrino is designated an antineutrino, 9-, that is, the emitted electron (lepton) and antineutrino (antilepton) cancel and give a net of 2ero leptons. [Pg.448]

In the last decade, neutrino experiments have demonstrated that neutrinos are massive particles which may oscillate among three autostates. Such experiments [77-82] have evidenced the mass difference between the autostates, but not the neutrino mass scale value. The only way to determine the neutrino mass is the knowledge of the shape of the end point of energy spectrum in beta decays. In the hypothesis of the Majorana neutrino (neutrino coincides with antineutrino and its rest mass is different from zero), the measure of the decay half-life in the neutrinoless double-beta decay (DBD) would be necessary. A number of recent theoretical interpretations of neutrino oscillation experiments data imply that the effective Majorana mass of the electron neutrino (as measured in neutrinoless DBD) could be in the range 0.01 eV to the present bounds. [Pg.357]

A nucleus (A Z) decays with the emission of two electrons (e ) and two antineutrinos (ve) following the equation ... [Pg.359]

Neutrinos Neutrinos and antineutrinos are formed whenever a positron particle is created in a radioactive decay they are highly penetrating. [Pg.1755]

Neutrinos are also generated by purely nuclear processes involving weak interactions, e.g. in the Sun. Such neutrinos can be an important cause of energy losses in compact stars through the Urea process, in which an inverse / -decay is followed by a normal fS-decay resulting in a neutrino-antineutrino pair. [Pg.10]

This is a process characteristic of nucleides with high n p ratios, and involving the loss of an electron from the nucleus, which is usually, but not invariably accompanied by the emission of y-photons. A detailed energy balance reveals that the simple picture cannot account for all the energy lost by the nucleus in the decay and the emission of an additional particle - the antineutrino, v is postulated to account for this. The general equation for a negatron emission is... [Pg.453]

This chain of events involved the so-called weak interaction, a puny and slow force compared with the strong and electromagnetic interactions. The weak interaction governs the conversion of protons into neutrons and vice versa, with creation of a neutrino (antineutrino). It thus determines the lifetime of free neutrons, which naturally decay into protons. In fact, neutrons have a life expectancy of around 10 minutes. However, before they disappear, they may have the opportunity to combine with protons, one which they readily accept. In that case, nuclear physics makes its appearance in the Universe. [Pg.203]

Beta-minus Beta-minus decay essentially mirrors beta-plus decay. A neutron converts into a proton, emitting an electron and an anftneutrino (which has the same symbol as a neutrino except for the line on top). Particle and antiparticle pairs such as neutrinos and antineutrinos are a complicated physics topic, so we ll keep it basic here by saying that a neutrino and an antineutrino would annihilate one another if they ever touched, but they re otherwise very similar. Again, the mass number remains the same after decay because the number of nucleons remains the same. However, the atomic number increases by 1 because the number of protons increases by 1 ... [Pg.274]

Is the neutron as we understand it today really a combination of a proton and electron as Rutherford envisioned it This is a philosophically interesting question. When neutrons decay, they produce a proton and an electron (and an antineutrino as well) however, these particles are not understood to have a real existence within an intact neutron. Indeed, the constituent parts of neutrons (and protons for that matter) are understood to be quarks. The phenomenon of neutron decay is explained by a transformation of one of its constituent quarks, turning the neutron into a proton the energy difference between the neutron and proton gives rise to the electron and antineutrino. [Pg.84]

Beta particles consist of electrons traveling at very high speeds. These electrons do not come from the electron shield of the atoms, but from the nucleus itself. In the (f-decay process, a neutron in the nucleus is transformed into a proton, an electron, and an antineutrino, P. For example, the nucleus of suffers the decay gC — + e+qP. In this equation, the electron e is called a [1 particle. [Pg.89]

The term antineutrino usually denotes an antiparticle whose emission is postulated to accompany radioactive decay by negatron emission, such as, for example, in neutron decay into a proton p+, negatron e and aiiliiieulnno IT, expressed by the equatiuii n p+ + e + vj. Capture of a neutrino by the neutron, ve + n - p+ + e would be an equally good description of the process. Positron emission is accompanied by a neutrino,... [Pg.1066]

Because the values of BJZ) are generally small relative to the masses of the nuclei and electrons, we shall neglect this factor in most calculations. Let us make a few calculations to illustrate the use of masses in describing nuclear phenomena. Consider the 0 decay of 14C, that is, 14C -> 14N+ + (3 + ve + energy. Neglecting the mass of the electron antineutrino, thought to be a few electron volts or less, we have... [Pg.30]

A number of studies have been undertaken of the interaction of neutrinos with nuclei, to determine the neutrino mass, and to show that neutrinos and antineutrinos are produced in (3+ and (3 decay, respectively. Neutrinos also provide important information about stellar nuclear reactions because they have a very low probability for interacting with matter and come directly out from the stellar interior. [Pg.215]

These reactions, called inverse (3 decay, were obtained by adding the antiparticle of the electron in the normal (3 decay equation to both sides of the reaction. When we did this we also canceled (or annihilated) the antiparticle/particle pair. Notice that other neutrino-induced reactions such as ve + n —> p+ + e do not conserve lepton number because an antilepton, ve, is converted into a lepton, e. Proving that this reaction does not take place, for example, would show that there is a difference between neutrinos and antineutrinos. One difficulty with studying these reactions is that the cross sections are extremely small, of order 10-19 bams, compared to typical nuclear reaction cross sections, of order 1 barn (10—24 cm2). [Pg.215]

Example Problem Estimate the flux of antineutrinos from an operating nuclear power reactor. For this estimate assume the power plant produces 1 GW of thermal power, that fission produces 200 MeV per event, and that there are approximately 6 rapid (3 decays per fission. [Pg.215]

Solution There is one antineutrino per 3 decay, of course, so this is really a problem in dimensional analysis ... [Pg.216]

Electron emission (ft -) A type of radioactive decay, where a neutron in the nucleus of an unstable atom converts into a proton and releases an electron and an antineutrino (compare with electron capture and positron emission). [Pg.448]

Beta-Minus Decay. Beta-minus decay is the radioactive decay process in which a nucleus emits an electron (also known as a beta particle, j3, or e ) and an antineutrino (v), which is a very weakly interacting particle with an extremely small mass. By weakly interacting, we mean neutrinos are so aloof from ordinary... [Pg.370]

The third force is the "weak nuclear" or "Fermi"4 force (1934), which stabilizes many radioactive particles and the free neutron it explains "beta decay" and positron emission (e.g., the free neutron decays within a half-life of 13 minutes into a proton, an electron, and an electron antineutrino). The weak force has a very narrow range. [Pg.6]

The final model that accounts for nuclear stabilities must, of course, be the strong force, or rather the residual component of the strong force that works outside of quark confinement. Natural or artificial radioactive nuclei can exhibit several decay modes a decay (N1 = N — 4, Z = Z — 2, A = A — 4, with emission of a 2He4 nucleus), which is dominant for elements of atomic number greater than Pb / -decay or electron emission (N1 = N — 1, Z = Z + 1, A = A this involves the weak force and the extra emission of a neutrino) positron or / + decay (N = N + 1, Z =Z — 1, A = A, emission of a positron and an antineutrino this also involves the weak force) y decay no changes in N or Z, and electron capture (N1 =... [Pg.14]

The decay of a free neutron qH1 electron antineutrino into a proton xpl, an electron e, and an... [Pg.67]

C-14 dating was discovered by Libby11 and co-worker [2], The cosmic ray flux has been fairly constant over prehistoric and current time and provides a small but almost constant supply of 6C14, at a rate averaged over the whole atmosphere of about 2.2 atoms cm-2 s 1. The radioactive 6C14 will bind to oxygen in the atmosphere to form radioactive carbon dioxide, but will decay, with a half-life fi/2 = 5730 years, by emitting an electron (or "fj ray") and an electron antineutrino ... [Pg.341]

Everywhere in the following discussions we will employ the single term neutrino, making a distinction between the neutrino and the antineutrino (as well as between the /3+ and /5 decays) only in those cases where the difference is essential. [Pg.294]


See other pages where Antineutrinos, decay is mentioned: [Pg.448]    [Pg.249]    [Pg.1639]    [Pg.41]    [Pg.41]    [Pg.42]    [Pg.717]    [Pg.1685]    [Pg.352]    [Pg.1043]    [Pg.1066]    [Pg.137]    [Pg.202]    [Pg.215]    [Pg.388]    [Pg.950]    [Pg.367]    [Pg.188]    [Pg.104]    [Pg.68]    [Pg.14]    [Pg.303]    [Pg.306]    [Pg.294]   
See also in sourсe #XX -- [ Pg.32 , Pg.68 ]




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Antineutrino

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