The 49ers have elected to break off negotiations with San Francisco city officials aimed at securing a new stadium at Candlestick Point and hope to build a home for the team near Great America in Santa Clara, the Mercury News has learned. Team owner John York informed San Francisco Mayor Gavin Newsom of the team's decision Wednesday. Peter Ragone, a spokesman for Newsom, said that York called the mayor Wednesday and told him, ``The 49ers no longer want to negotiate'' with the city.