What is an Exchange Particle? A-Level Physics Explained

[Daniel Wqw]

I really want to understand the answer to this question.
Q: What is an exchange particle?
A: A virtual particle that let's force act between particles in an interaction.
This answer was given in my A-Level textbook but I can't for the life of me decode what it means. For example in beta minus decay (feynman diagram given below) the exchange particle is the W- boson. But how does the W- boson let force act between the particles in this interaction.
I would be grateful for any response but please bear in mind that I am an A-Level physics student (british high school) so am likely not to understand anything too complicated. Thanks!

 

[Orodruin]

I would say it would be more appropriate to say that it is a virtual particle which allows other particles to interact and exchange momentum and/or energy. The concept of force seemingly refers back to a more classical setting while virtuality itself is a QM concept.

The main thing here is that the exchange particle can be virtual, which mens that its energy and momentum do not follow the classically allowed.

 

[ChrisVer]

"force" because it changes the momentum...in a "word-misuse" context...