By Martha Brennan & Charlotte McIntyre Cillian Murphy said he hasn’t given much thought to the prospect that he could win an Oscar. The Irish actor is in the running for Best Actor at the 96th Academy Awards for his portrayal of J Robert Oppenheimer in Oppenheimer. Murphy, 47, said he hasn’t let himself imagine what it would be like to lift the trophy on Sunday night. He said: “I haven’t really thought about it to be honest. I just want to go in and have a good time. I’m sure we’ll have a party of some sort. It’s really not competitive. It might appear that way but it’s really not. “It feels r…