libgdx - Camera Coordinate To Screen Coordinate

I want to convert the camera coordinate to screen coordinate. I have asked this question because my camera is 48m wide and 32m high but my screen is 480x320 pixels. So whatever collision point I get those are based on camera. Also I like to mention that my camera set at center of the screen. So I get (0,0) coordinate at middle of the screen. At collision time I put some particle effect but now that particle effect not at correct place in the screen. So someone from community please help.