Difference in eta, phi values before an after Delphes

[Michael Albergo]

Hi there,

I am running the particle gun example for the Pythia+Delphes combination. I edited the DelphesPythia8.cpp file to allow me to write the values of eta, phi, transverse momentum before smearing, etc before these events are put through delphes. I want to compare the outputs for a project I'm working on, and from my understanding only the PT should be different based on how the delphes card is written. That is, only the PT has a resolution smearing on it from the list of eta, phi, and PT.

I am trying to match the electron events to the eta and phi values before and after smearing, but the root file produced after running through delphes has slightly different eta and phi values than the text file (in the 100ths to 1000ths place in decimal).

Do you know why that might be, or how I can correctly get the eta, phi, and pt before running it through delphes for just the electron events in delphes?

Thanks for any clarification on why these numbers might be different.

However, when I load the eta and phi values

[Pavel Demin]

Have you tried to compare the momenta in the Particle and in the Electron branches?