A Norwegian company seeking to develop a male birth control pill has signed a licensing agreement with the University of Massachusetts Medical School covering research that could lead to a drug to block sperm’s ability to swim and fertilize an egg. The method that led to the long-term deal announced Monday could expand the decades-long search for a male pill by targeting a protein found only in sperm cells. Researchers at the University of Massachusetts in Worcester and elsewhere say that approach carries far less risk of side effects than manipulating a man’s hormones, the avenue that has attracted the most research aimed at finding alternatives to condoms and vasectomies.