Treasuries are sold at auction, so supply/demand factors in as well. Since treasuries have little to no credit risk and they're highly liquid, people are generally just concerned with inflation. As roymurdock said, the FFR has minimal impact on long term rates. Here's Bernanke saying the same thing:
"The Fed’s ability to affect real rates of return, especially longer-term real rates, is transitory and limited. Except in the short run, real interest rates are determined by a wide range of economic factors, including prospects for economic growth — not by the Fed."
http://www.brookings.edu/blogs/ben-bernanke/posts/2015/03/30...
"The Fed’s ability to affect real rates of return, especially longer-term real rates, is transitory and limited. Except in the short run, real interest rates are determined by a wide range of economic factors, including prospects for economic growth — not by the Fed." http://www.brookings.edu/blogs/ben-bernanke/posts/2015/03/30...