Muon Decay Constant: Find Mean Lifetime & Lambda

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Discussion Overview

The discussion revolves around the muon decay constant, specifically the relationship between the decay constant (lambda) and the mean lifetime of muons. Participants explore the sources for these values and raise questions about muon flux at different altitudes. The conversation includes aspects of theoretical understanding and practical data retrieval.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant inquires about the decay constant of a muon and references a Wikipedia article that states the decay constant is the reciprocal of the mean lifetime.
  • Another participant provides the half-life of the muon, approximately 2 microseconds, and explains the relationship between the decay constant and half-life.
  • A third participant shares a link to a resource listing the lifetimes of both positive and negative muons.
  • Some participants challenge the assertion that positively and negatively charged muons have different lifetimes, stating that they are equal.
  • There is a request for data on muon flux at different altitudes, specifically the number of muons per square meter per second at 5000m and at ground level, without delving into complex equations.
  • One participant emphasizes the importance of measuring both muon types' lifetimes to verify CPT invariance, but another participant argues this point is not relevant to the original question.

Areas of Agreement / Disagreement

Participants express disagreement regarding the claim that positively and negatively charged muons have different lifetimes, with some asserting they are equal. The discussion on muon flux data remains unresolved with no consensus on where to find such information.

Contextual Notes

The discussion includes references to specific resources for muon lifetimes and decay constants, but lacks detailed information on the methodology for measuring muon flux at different altitudes. There are also unresolved assumptions regarding the relevance of certain points to the original inquiry.

RK1992
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muon decay constant/ muon flux

where can i find the decay constant of a muon (the lambda which appears in):
[URL]http://upload.wikimedia.org/math/3/f/2/3f28b1c0d4362b86a89f976d83d81070.png[/URL]

thanks

edit:
oh the wiki page http://en.wikipedia.org/wiki/Exponential_decay
gives the relationship that the decay constant is the reciprocal of the mean lifetime
is that correct?
 
Last edited by a moderator:
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Typically you will find the half-life tabulated, which for the muon is about 2 microseconds. As the Wikipedia article you cited states, the decay constant is related to the half-life as follows:
\lambda = \frac{ln(2)}{t_{1/2}}
 
Bob seems to be suggesting that positively and negatively charged muons have different lifetimes. This is not the case.
 
Vanadium 50 said:
Bob seems to be suggesting that positively and negatively charged muons have different lifetimes. This is not the case.
i can see that the ratio is almost 1:1 for the mean lifetimes :)

but my other question is where on Earth are you supposed to obtain simple data on muon flux at different altitudes - like at the height where they are generally created and at ground level? I am not looking for partial differential equations and all that, just for example the number of muons through a metre sqaured area per second at a height of 5000m and the number of muons through a metre squared per second at ground level
 
Last edited:
Vanadium 50 said:
Bob seems to be suggesting that positively and negatively charged muons have different lifetimes. This is not the case.
The measurement of both positive and negative charged muon lifetimes is an important test to verify that they are equal, as required by CPT invariance. See second table on page 2 of

http://pdg.lbl.gov/2004/listings/s004.pdf

Bob S
 
Bob S said:
The measurement of both positive and negative charged muon lifetimes is an important test to verify that they are equal, as required by CPT invariance.

True, but irrelevant to what the OP asked. Please don't sidetrack the thread.
 

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