hadron | modular backend with a dependency injection pattern | Runtime Evironment library

Which you use depends on what relationship you're trying to model.

Composition isn't always the better option. "Composition over inheritance" is often repeated because inheritance is often abused with the idea that it reduces the amount of code that you need to write. That's entirely the wrong motivation to base your decision on though.

If you have two classes, A and B, a rough, general guide is:

• If B is an A, you probably want inheritance.
• If B has an A, you probably want composition.

In your case here, from my extraordinarily limited knowledge of particle physics, a Hadron is a Particle, so inheritance is probably a better fit. A Hadron doesn't contain/have a Particle, so I think you're trying to work against the grain by forcing composition here.