Sensor question

I'm trying to determine which P&S has the largest CMOS sensor?  I do a lot of shooting in low-light places like museums, etc. and I need a P&S that will do the best job possible (for a P&S) under those conditions.  I can NOT use flash in most instances in these surroundings.

I know..."use a DSLR"...but please don't ask.  In some of these environments I can't be saddled with a bulky camera.  If there is nothing out there good...at least I'd like to know which is the best of the bad so I can try it.  Thanks!