Theoretical Knowledge for Experimental Particle Physicist I was told that, as an experimental particle physicist, I need to know Quantum Field Theory and the Standard Model.  However, are there situations where an experimental particle physicist needs to know/learn any of the following?

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*Astroparticle Physics

*Quantum Field Theory in Curved Spacetime

*String Theory

In case this is too opinion-based, let the question be: are there any experimental particle physicists who learnt any of the above in order to do research or written papers on any of the above?
 A: I agree with Nickolas Alves answer, and can add the following:
Particle physics experiments involve many physicists, and all their names are in all the papers usually, even though some have contributed only to the technical part, and few are really experts in the particular analysis of data published.
If one wants to contribute to analysis for experiments in the  list you give above , courses  would be very helpful. In my case about more than twenty years ago I was interested to see whether in our data one could detect large extra dimensions in our experiment at the time (LEP) and had to read up. A course would have been useful.
The LEP energies were not enough for  useful limits, but this summary poster  by ATLAS in LHC

"ATLAS searches for extra dimensions using the full Run 2 ee and mm datasets"

shows there is active analysis going on.
The  people carrying   out this analysis will   have taken a course in string theory
A: I wanted to post this as a comment, but it was getting too long and way too similar to an answer. For now, I hope it is useful, but I also hope someone posts a more credible answer later on.
I'm a theoretician in QFTCS, so I'm going way out of my area in this answer, but I guess it is going to depend heavily on what exactly you mean by experimental particle physics. Let us consider a couple of examples.

*

*LISA is a gravitational wave detector planned that might obtain information on the electroweak phase transition;

*DarkSide, if I'm not mistaken, detects particles from cosmic sources to obtain information about dark matter. I believe SuperKamiokande also detects particles from astrophysical sources;

*the LHC is a collider performing experiments completely different from the previous two.

As far as I know, someone at LISA might want to consider gravitational effects, meaning Quantum Field Theory in Curved Spacetime (QFTCS) and even some approaches to Quantum Gravity (such as String Theory) might turn out to be interesting. Someone at DarkSide or at the SuperKamiokande might want to understand how Particle Physics relates to astrophysical processes. Someone at the LHC could not need to deal with any of these possibilites (depending, of course, on the details of the experiment).
In short, "are there situations?" Definitely. It boils down to what sort of problems you are interested in and what sorts of theory you are interested in. Are there situations in which Functional Analysis is interesting for physicists in general? Definitely, as illustrated on this question, for a single and simple example. Nevertheless, most physicists can get away most of the time with formal manipulations in Quantum Mechanics. One must choose, however, whether they prefer to learn Functional Analysis or some other topic in Physics which might end up being more interesting for their work in particular.
