Thanks for passing by, and don't worry for the question. There is no dumb question (sometimes there are however dumb answers :D ).
If dark matter was being produced in the LHC, wouldn't it have affected the trajectories of charged particles differently? Or is that something already in the energy/momentum discrepancies you mentioned?
Being very weakly interacting, dark matter particles produced at the LHC leave the detector without interacting with anything. Nevertheless, the trajectories off all the other particles produced in the event are impacted as momentum is conserved. Therefore, there is an impact, that can be measured through energy-momentum conservation.
Does it clarify?
Cheers!
Thank you for your reply, yes super clear.
But was there an explanation for this imbalance in energy and momentum conservation other than it being possibly caused by dark matter, or was it just "ignored" before?
There is an irreducible background coming from the Standard Model (neutrinos), as well as an instrumental background coming from the non perfect identification efficiency of the detectors. For the moment, all measurements of a 'missing momentum signal' are compatible with the above expectation. In other words, we measure some momentum imbalance, but this is well explained by the Standard Model and experimental effects. For instance, let's take the image below from the CMS collaboration of the LHC.
[Credits: PRD 97 (2018) 092005 (CC BY 4.0)]
It shows the transverse energy imbalance obtained in certain collisions. Data (black dots) agrees very well with the Standard Model expectation (the sum of the coloured histograms). A potential signal should materalise as an excess on this curve, that is not seen.
Ok, thank you very much for taking the time to explain this.
Much appreciated!
You are very welcome! The pleasure was mine :)