sPHENIX bulk physics topical group

[Vladimir Bumazhnov <bumaznov AT rcf.rhic.bnl.gov>]

                      Dear Apurva and All,
I have some questions on the 'Bulk_TG_2_6 - 02-06-24-pi0-vn-update-v2.pdf'
If some questions have already been asked at the presentation, please 
skip such my questions.

1) page 6    I can see that 2-nd order correction does not give 
anything. And probably increases the  stat  error. May be it is not
needed?

2)You measure the azimuthal angles of the particles relative to the 
event plane. EMCal overlaps the area (-1.1,1.1) by eta.
You determine the event plane by MBD. MBD overlaps the areas (3.56 , 
4.45 ) and (-4.45,-3.56).
How will the event plane determined by MBD differ from the event plane 
determined by the charged particles
in the central region (from TPC) ?

3) page 14   I do not understand the expression for correction of 
V2_pi0. It may be better to try this approximation:
   V2_M = V2_pi0/N_pi0 * n_pi0 + V2_bg/N_bg * n_bg     and then
   V2_pi0 = [V2_M - V2_bg *(n_bg/N_bg)] * (N_pi0/n_pi0)
  Here N_pi0 is the number of pi0's in signal region (μ±2σ) , n_pi0 is 
the number of pi0's in selected part of signal region
 (μ±x) and |x|<=2σ. At (|x| = 2σ ) n_pi0 = N_pi0. N_bg is the number of 
diphoton combinations in background region (μ+3σ, 0.5 GeV) and
 n_bg is the number of background diphoton combinations in the same 
signal region  (μ±x) and |x|<=2σ.


With best regards,
                     Vladimir