unsure whats happening

ok. charlie has been with us since he was 8 weeks, he's now 15 months. We got arthur 6 weeks ago. Initially charlie ignored him and spent a lot of time outside/in another room, then charlie began attacking arthur and hurting him so they were seperated and re introduced and they began to plat together and sometimes charlie would get rough. Now tho, when ever arthur goes near or tries to play with charlie, charlie meows like he s really unhappy and tries to get away. I dont understand whats happening here but my charlie does not seem like a very happy little boy at all. If charlie is eating and arthur goes near his food, he'll move away and let arthur eat it. Does this mean that arthur is the more dominant cat? And can I do anything to make charlie happier?
Thanks guys

Anytime you bring a new kitty into the mix it will take some time for them to adjust. I brought a new kitten into our home about 3 months ago and there is still some degree of adjusting happening.

Alot of what you are describing are some of the same things we have gone through. My suggestion is just to let your older kitty Charlie know that he is still just as important and give him lots of hugs and kisses

The moving-away-and-letting-him-eat is normal too - mine did that when a new 'boy' moved in, and while they're best playmates, I think the older one (12) is just accepting his place in things as no longer being #1 cat - so I help him out by shooing away the other one (2 yrs now) when they're eating (#2 is a piggie and finishes too fast!).