What does a QCD background refer to?

[martinhiggs]

Hi!

I'm currently performing lots of research into the Higgs Boson. In many papers, when talking specifically about production and decay mechanisms, they talk about the "high QCD background". I can't find a specific definition for what this means and refers to.

Any clarification would be appreciated :)

 

[tom.stoer]

I guess you are interested in proton-proton collision at the LHC.

The Higgs boson is produced via electro-weak processes, but almost all events that are detected are due to the strong interaction. Therefore all these events are "background" and have to be subtracted to get the electro-weak Higgs signal.

There would be no such problem with an electron-positron collider b/c no strong interacting particles are present.

 

[GreyBadger]

In experimental terms, it's a bit of a bastardised term (CMS publication guidelines are explicit in not allowing it, along with other phrases such as 'more statistics' - we use these colloquially, but they shouldn't be in our published work).

What it generally refers to are processes which lead to two hadronic jets in the final state. These can fake things such as electrons, and their cross section is very high. We spend a lot of our time quantifying the probability of a jet to fake a certain physics object, and take this into account in our background computations.