Regarding Angular Smearing in Track

[Jihee Kim]

Dear Delphes experts,

I would like to ask you about additional angular smearing that I have observed. In detector card, CtgTheta and Phi both resolution formula were set to be 0.0. When I used single charged pion particle gun, I see no angular smearing in pseudo-rapidity and azimuthal angle in Track branch and this was what I expected from detector card setting (Please see figures in left hand side). However, when I ran delphes with Pythia8 generator creating DIS events, I looked into charged pions from K short particle decay and found larger angular smearing in azimuthal angle only comparing to pseudo-rapidity in Track branch (Please see figures in right hand side). I would expect consistency on this matter. Also for instance, charged pions from D zero particle decay have almost no smearing in azimuthal angle and pseudo-rapidity. Would you be able to give me some explanation on what can cause this? Thank you!

Best regards,
Jihee