For particle physics, I can recommend this that I wrote many months ago. It gives link to several introductory posts on particle physics.
For the neutron stars, I am by far not an expert, but this is a great start.
From there, we can of course continuing discussing (and feel free to question me).
Thank you very much @lemouth :-)
Very kind for picking out the links. I hope to update my knowledge in these regions. I also picked out some stuff, just need to find a quiet hour to get in it.
If I have further questions, I will come back to you :-)
I repeat: please don't hesitate :D