- #1
ChrisVer
Gold Member
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I am just looking for a verification of logic, and maybe some feedback?
I was thinking how the following decay:
[itex] \tau \rightarrow e \nu_\tau \nu_e[/itex]
can be misidentified by the detector (let's say ATLAS) as a hadronically decaying tau (and so the electron seen as a jet).
First of all I don't think that the tracking system can help in distinguishing an electron from a single charged pion (1prong tau decay). That's because they same charge and for momenta p ~GeV they are both indistinguishable (highly relativistic). So in the tracking system it's easy to lose that information...
Then I'm looking at the calorimeters...and here is the point that confuses me...
The distinguishment can be applied by looking at jet energy deposits in the HCAL and matching it to possible energy deposits in the ECAL. The electron is not supposed to give a signal in the HCAL and so we can make sure that the charged object is a hadron.
However this logic rules out any kind of misidentification, so how does this happen in real life...? Is it because the electron's EM showers can be over-extended and so misidentified as jets? I am attaching a picture of my logic...
I was thinking how the following decay:
[itex] \tau \rightarrow e \nu_\tau \nu_e[/itex]
can be misidentified by the detector (let's say ATLAS) as a hadronically decaying tau (and so the electron seen as a jet).
First of all I don't think that the tracking system can help in distinguishing an electron from a single charged pion (1prong tau decay). That's because they same charge and for momenta p ~GeV they are both indistinguishable (highly relativistic). So in the tracking system it's easy to lose that information...
Then I'm looking at the calorimeters...and here is the point that confuses me...
The distinguishment can be applied by looking at jet energy deposits in the HCAL and matching it to possible energy deposits in the ECAL. The electron is not supposed to give a signal in the HCAL and so we can make sure that the charged object is a hadron.
However this logic rules out any kind of misidentification, so how does this happen in real life...? Is it because the electron's EM showers can be over-extended and so misidentified as jets? I am attaching a picture of my logic...