Earthworms have no sense of hearing, and no sense of smell, but are very light & touch sensitive. It could possibly be argued that they can "hear" through sound wave vibrations... Would make for a great science fair experiment! 
DO Worms Have Ears?
Look in www.wikipedia.org. I did, but there was no mention of how they hear. Very interesting, they can have up to 9 and 10 hearts! Hope this helps.
No they can't hear, see, smell or taste, they can feel things though.