- #1
What is the distribution of energy for beta-minus decay?
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Discussion Overview
The discussion revolves around the energy distribution in beta-minus decay, specifically questioning the shape of the energy spectrum and the implications of the neutrino's role in this process. Participants explore theoretical aspects, interpretations of graphical representations, and the underlying physics of the decay process.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant questions the accuracy of a book's depiction of the energy spectrum for beta-minus decay, suggesting it should resemble a normal distribution instead.
- Another participant references an external source, indicating that the energy spectrum's form necessitated the introduction of the neutrino in beta decay reactions.
- There is a mention of the electron momentum appearing more symmetrically distributed, which contrasts with the energy distribution.
- A participant discusses the influence of nuclear Coulomb interaction on the energy distribution, noting it shifts the distribution toward lower energies due to attraction between the daughter nucleus and emitted electron.
- Concerns are raised about the implications of momentum conservation, particularly regarding the presence of electrons with zero kinetic energy when the parent nucleus has zero momentum in the center of mass frame.
Areas of Agreement / Disagreement
Participants express differing views on the shape of the energy distribution and the implications of momentum conservation, indicating that multiple competing perspectives remain without consensus.
Contextual Notes
Some assumptions regarding the nature of the energy distribution and the role of the neutrino are not fully explored, leading to unresolved questions about the relationship between kinetic energy and momentum in the context of beta-minus decay.
- #2
sniffer
- 112
- 0
halo guys.
can somebody help me with this simple question please ...
can somebody help me with this simple question please ...
- #3
seratend
- 318
- 1
sniffer said:halo guys.
can somebody help me with this simple question please ...
Ok.
See http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/beta.html#c5. It was this form of the energy spectrum that has required the physicists to introduce the neutrino in the beta decay reactions.
Seratend.
- #4
Astronuc
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seratend said:
Which will lead to - http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/fermi2.html#c1
Interestingly, the electron momentum seems more normally (or at least symmetrically) distributed.
- #5
Igor_S
- 98
- 0
I don't quite get this, either.
If the question is about why is distribution symmetrical or not, answer is given here :
"It accounts for the nuclear coulomb interaction which shifts this distribution toward lower energies because of the coulomb attraction between the daughter nucleus and the emitted electron. (It shifts the distribution upward for positrons.)"
If you were wondering why is there finite "cutoff" at 0 kinetic energy and not finite (in the sense it's zero) at 0 momentum, I don't know. This doesn't make sense...
And if the parent nucleus has zero momentum in CM frame, how come there is a finite number of electrons with zero kinetic energy ? That should mean that in that case, neutrinos are also having zero kinetic energy (conservation of momentum). Now if there comes up electron with nonzero kin. energy, then neutrino should also have nonzero kin. energy, and sum of energies in this case and in the case where they are both just "standing" is different.
If the question is about why is distribution symmetrical or not, answer is given here :
"It accounts for the nuclear coulomb interaction which shifts this distribution toward lower energies because of the coulomb attraction between the daughter nucleus and the emitted electron. (It shifts the distribution upward for positrons.)"
If you were wondering why is there finite "cutoff" at 0 kinetic energy and not finite (in the sense it's zero) at 0 momentum, I don't know. This doesn't make sense...
And if the parent nucleus has zero momentum in CM frame, how come there is a finite number of electrons with zero kinetic energy ? That should mean that in that case, neutrinos are also having zero kinetic energy (conservation of momentum). Now if there comes up electron with nonzero kin. energy, then neutrino should also have nonzero kin. energy, and sum of energies in this case and in the case where they are both just "standing" is different.
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