converted photons

[Urs]

Hello,

I am unsure about converted photons in Delphes 3.

In ​arXiv:1307.6346v3 you write nothing about converted photons in section 2.1 (Particle propagation). In section 3.1.2 (Photons) you write "Photon conversions into electron- positron pairs are neglected". The latter arguably means that the photon list does not contain any converted photons. But the absence of conversions in 2.1 would imply that Delphes does not do any photon conversions (i.e. all photons lead to an energy deposition in the ECAL at a location expected for the photon). Is my interpretation correct?

Apologies if I missed this somewhere.

Cheers,
--U.

[Michele Selvaggi]

Hi,

indeed, photons are not converted in Delphes, as particle-matter interaction is not simulated (as in Geant4). Particles in Delphes are simply propagated in the tracker volume without interacting with the tracker material, which is ultimately responsible for photon conversions.
However it is always possible (although not trivial), if you know the conversion probability as a function of pt,eta of the incoming photon, to write a module that creates the e+e- pair with the above probability.

This said, conversions can be accounted properly only by means of a genuine detector simulation.

Michele