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Re: Helix and FairTrackParH [message #9069 is a reply to message #9061] Fri, 24 July 2009 13:18 Go to previous message
StefanoSpataro is currently offline  StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino
first-grade participant

From: *to.infn.it
Quote:


Ok, it' s just a matter of names Wink
Ok, but you can
If you have a look in the FairTrackParH.h, the comment at the beginning contains the 5 parameters:
q/p, lambda, phi, y_perp, z_perp
In the code the name of the parameters are:
fLm = lambda
fPhi = phi
fX_sc = x_perp
fY_sc = y_perp
fZ_sc = z_perp



It is a matter of names only if you know what those names mean (not my case) Smile And once they are also called in a different way, the amount of confusion in my mind increases.

However, it seems I do not need those parameters for my helix, even because all the defnitions are to move from one system to another, but what I need is how the position/momentum variates along the track.
I have found a document in internet that explains what I need, to characterize my track:

center of the helix (to calculate drho, and phi0)
radius of the helix (to calculate drho)
pt (to calculate k)
lambda


Of these 5 params, I have already lambda, pt, and the radius can be calculated from p. I am only missing the center of the helix, that can be calculated with the suggested method of Gianluigi.

I will try and cross my fingers hoping that it will work.


 
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