Some question about the MET, mainly about the Eta of the MET.

[tangyilei]

I am now curious about the MET. Although usually the transverse part of the missing energy is used, it seems that the results of the root files that Delphes generated do contain a "Eta" to every key MET in each event. Does that mean that the parrallel part of the missing energy is also calculated? By the way, is the missing energy calculated by summing over all the momentum of the detected particles? I ask this problem because it seems that when a PDG code of a stable particle, e.g. dark matter, is not assigned as the PDG code of the neutralino, it seems that the missing energy spectrum is wrong. So, could you tell me that whether these missing energis, no matter tranverse to the beam or parallel beam, is calculated out of the summation over all detected particles, or directly from the momentum of the particles with particular values of PDG code?

[Michele Selvaggi]

Hi,

yes we provide also the eta of the missing energy (equivalent of pz), although of course this can be interpreted as a true missing energy only in the context of an e+ e- collision. The missing energy is calculated as a sum of all detected particles indeed.

If you have in your model some particle that should go undetected, you should add that particular PDGcode in the calorimeter section of the card you are using and specify that it should not deposit any energy.

Something like line 270 in here:

​https://github.com/delphes/delphes/blob/master/cards/delphes_card_CMS.tcl

Cheers,
Michele