# Muon decay constant

1. Sep 18, 2010

### RK1992

muon decay constant/ muon flux

where can i find the decay constant of a muon (the lambda which appears in):

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: Apr 25, 2017
2. Sep 18, 2010

### phyzguy

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:
$$\lambda = \frac{ln(2)}{t_{1/2}}$$

3. Sep 18, 2010

### Bob S

4. Sep 18, 2010

Staff Emeritus
Bob seems to be suggesting that positively and negatively charged muons have different lifetimes. This is not the case.

5. Sep 18, 2010

### RK1992

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? im 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: Sep 18, 2010
6. Sep 18, 2010

### Bob S

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

7. Sep 18, 2010