Multidimensional Regression on LHC collision jets background cover

Multidimensional Regression on LHC collision jets

Model the behavior of particle jets from LHC collisions using advanced Quantum Algorithms to bridge theoretical predictions with observed data.

CERN

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CERN

Marcin
marcinj8

2

Posted

Some events seem to have empty jet outputs

Hi, I found some events in the jets file which seem to be "empty" - meaning, all values for the momenta of the jets are 0. Do you know if I should be interpreting those as events without jets - aka where no jets are considered a valid outcome of an interaction or rather as faulty datapoints to be removed.
Also maybe I just processed the data wrong somehow, can anyone else identify having such events? e.g. ids 2151, 2970
Thanks :)

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Yacine Haddad

2

Posted by yhaddad

The data is structured as follow, if no jet is found then then this means both jets are below 30 GeV threshold and this event can be discarded. It is possible to have this special case.
So you can basically make a selection to choose the right events to work with. For example, can do:
jets_p4  = jets_p4[jets_p4.pt>30] 
partons_p4 = partons_p4[jets_p4.pt>30]
How many events do you see that have zero's everywhere?

Marcin

2

Posted by marcinj8

Thanks for this! I'm seeing 314 events with no jets.

Yacine Haddad

1

Posted by yhaddad

That's seems about right. We are should see some events that are expected to fall beyond the detection phase-space. I think it is safe to consider neglecting these events at the moment. For instance you can required to have n_jets >= 1 so you can have at least one object in the final state.

Marcin

1

Posted by marcinj8

Also, is that a general feature of the way the data is produced? Aka, if my solution returns some jets with pt<30, they will never be correct?

Yacine Haddad

2

Posted by yhaddad

Yes it is a general feature of the way the data is produced. In the current challenge we want to know how we can produce 2 jets and above. so at the end we don't evaluate the solution when jet are below 30 GeV. The KL divergence is calculated for the following bins :
pt_bins = [30, 40, 50, 60, 70, 80, 90, 110, 140, 180, 230]
n_jets_bins = [2, 3, 4, 5]
At the end, in your solution is it more important to model events with at least 2 jets.

Jannes Stubbemann

1

Posted by stubbi

@marcinj8 thanks for brining this up! We will check with the competition host and ask them to come back to you!

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