sPHENIX tracking discussion

[Hugo Pereira Da Costa <hugo.pereira-da-costa AT cea.fr>]

Hi Tony, others,

following on today's discussion at the Distortion Software meeting, I 
calculated the fractions of the upsilon signal that goes into the tails 
and Gaussian core. The result is "interesting".

For the nominal signal (no distortion) you get:

 core: 6%
 left tail: 93%
 right tail: 1%

And for the signal after distortion + reconstruction:

Fractions:
 core: 4%
 left tail: 93%
 right tail: 3%

So in both cases the "gaussian core" fraction is actually very small. 
The signal is dominated by the left side power law. I think this makes 
sense because when the resolution is good, what dominates the 
distribution is really the radiative decays of the upsilons. This is 
also illustrated in the two attached plots, where the vertical lines 
represent when the function switches from power law to Gaussian (on 
either sides). Note that, according to the fit a significant fraction of 
the signal also goes beyond the left limit of the plot (m < 7 GeV/c2).

As for the actual difference between nominal and 
distortion+reconstruction, it lies in the right tail mostly, which grows 
from 1% to 3% of the total signal.

Comments welcome,


Hugo

Attachment: InvMassUpsilon_cb2_upsilon_truth_micromegas_nominal.pdf
Description: Adobe PDF document

Attachment: InvMassUpsilon_cb2_upsilon_truth_micromegas_corrected_mm-new-loose_extrapolated.pdf
Description: Adobe PDF document