Finding Maximum and Minimum Energy of Electron in Particle Disintegration

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Homework Help Overview

The problem involves a particle disintegration reaction where a muon decays into an electron and two neutrinos. The original poster seeks to determine the maximum and minimum energy of the electron based on conservation laws.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster discusses using conservation of energy and momentum to find the electron's energy, questioning how to determine the minimum and maximum values of the momenta of the neutrinos. They propose that the maximum energy of the electron occurs when the neutrinos' momenta are equal and opposite.

Discussion Status

The discussion is ongoing, with the original poster seeking clarification on their reasoning and the validity of their assumptions. Some participants have commented on the appropriateness of the forum for the topic, indicating a mix of interpretations regarding the complexity of the problem.

Contextual Notes

There is a mention of the problem being categorized as advanced physics, suggesting that it may require a higher level of understanding than typical introductory physics problems. The original poster expresses concern about the language barrier, which may affect their communication in the forum.

Tolya
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First, sorry for my English. I'm not very well in it... Please, try to understand :)
The problem.
We have reaction: [tex]\mu \rightarrow e + \nu + \tilde{\nu}[/tex]
We know energy of myuon - E.
Question: Find the maximum and the minimum energy of electron.

My attept:

Conservation of energy: [tex]E = E_e+E_{\nu}+E_{\tilde{\nu}}[/tex] (1)
Conservation of impulse: [tex]\vec{p} = \vec{p_e}+\vec{p_{\nu}}+\vec{p_{\tilde{\nu}}}}[/tex] (2)

The mass of the rest of neutrino and antineutrino is 0. So, [tex]E_{\nu}=p_{\nu}c[/tex]
[tex]E_{\tilde{\nu}}=p_{\tilde{\nu}}c[/tex] and from the first equation:

[tex]E_e = E-c(p_{\nu}+p_{\tilde{\nu}})[/tex]

Therefore, we must find the minumum and the maximum value of [tex](p_{\nu}+p_{\tilde{\nu}})[/tex] Then, the minmum value of this expression gives us the maximum value of [tex]E_e[/tex] and the maximum value gives the minimum of energy. Am I right in this statement?

From (2):
[tex]\vec{p_{\nu}}+\vec{p_{\tilde{\nu}}}} = \vec{p} - \vec{p_e}[/tex]
Also we know that: [tex]p= \sqrt{\frac{E^2}{c^2}-m^2c^2}[/tex]
and: [tex]p_e= \sqrt{\frac{{E_e}^2}{c^2}-{m_e}^2c^2}[/tex]

How can I find the minumum and the maximum value of [tex](p_{\nu}+p_{\tilde{\nu}})[/tex] with the help of all I wrote here? :)

I also have an assumption that we can find half of the answer simply in the following way:
[tex]E_e[/tex] reaches its maximum when impulses of neutrino and antineutrino have opposite directions and equals in absolute. (It's easy to understand this fact because in this case impulses of neutrino and antineutrino compensate each other and the value [tex]p_e[/tex] reaches its maximum, so does [tex]E_e[/tex]). Then, almost easy:
[tex]p=\sqrt{\frac{E^2}{c^2}-m^2c^2}=p_e=\sqrt{\frac{{E_e}^2}{c^2}-{m_e}^2c^2}[/tex]
And we have: [tex]E_e^{max}=\sqrt{E^2+c^4({m_e}^2-m^2)}[/tex] Am I right? How can I find the minimum value of [tex]E_e[/tex]?

Please, help.
 
Last edited:
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No issue with the language, except that I am curious about what country considers beta or weak decay to be "Introductory Physics"
 
Last edited:
sweden do =)

And also, there are guys posting mass falling to the Earth without corilos and centrifugal terms in the advanced forum. Very hard to get everything right here..
 
I'm very sorry, what forum corresponds to this theme?
 
Tolya said:
I'm very sorry, what forum corresponds to this theme?

Well, it's not a problem really, but this topic is appropriate for the Advanced Physics HW forum. This is upper level material as opposed to introductory physiscs.
 
Please, delete this theme. I posted this problem in "Advenced Physics".
 

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