How to express particle momentum in [rad]

  • Thread starter 1Keenan
  • Start date
  • #1
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Hi all,

I need to use the output of a simulation code in another code who accepts totally different format for data.
Now, the file I have has 5 column with positions and momenta of a certain number of particles (momenta are dimensionless - normalized to electron mass times c (light speed) )
The other code wants momenta expressed in [rad] but I don't know how to convert them...
COuld you help me?

Thanks a lot
 

Answers and Replies

  • #2
35,395
11,751
What is a momentum expressed in rad? Is that some angle of the flight direction?
You'll have to check the documentation how that angle and other parameters are defined.
 
  • #3
100
3
Documentation is very poor.
Anyway I think I have to evaluate it in this way:

arcosin (ModulusP/py)
 
  • #4
Khashishi
Science Advisor
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493
There's not enough information here to be sure, but rad might mean radians, which are used as units of rapidity. http://en.wikipedia.org/wiki/Rapidity

Are you working with highly relativistic particles?
 
  • #5
Vanadium 50
Staff Emeritus
Science Advisor
Education Advisor
26,821
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This is not rapidity.

cos-1(|p|/py) is already in rads/ That is, |p|/py is already dimensionless.
 
  • #6
100
3
This is not rapidity.

cos-1(|p|/py) is already in rads/ That is, |p|/py is already dimensionless.

Yes, I think this is the way.
But now I have another problem: 3rd component of momenta is defined as Dp/pn (n = particle numeber).
But it is not very clear in the documentation how Dp is defined.
I think it is the average momentum - pn, but in this way I have an error message saying gamma < 1...

This is making me crazy...
 

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