This study is aimed to instigate if the shape of pseudorapidity distribution of electrons from J/psi decays, observed in J/psi embedding for p+p 200 GeV (http://portal.nersc.gov/project/star/btrzeciak/embedding/Jpsi_pp2006/qa_2006_P06id_Jpsi_full.pdf, page 13)) is due to J/psi kinematics.

I generated Monte Carlo J/psi->e+e- decays for:

• real pT and rapidity spectrum (labeled as "Pythia" on plots)
• flat pT and rapidity spectrum

I generated J/psi with pT<6 GeV and |y|<1.5.  I selected electrons with |eta|<1.5.

There is no experimental effect included. 

Results for both cases show a evolution of shape of eta distribution with pT, which is similar to that seen in embedding (from "V"-like at very low pT to gaussian one at hight pT). The shape in embedding for pT < 1.5 GeV is not reproduced - this maybe due to  reconstruction efficiency for |eta|>0.5.