Central bankers began arriving for their annual policy symposium in Jackson Hole as economists from Citigroup Inc. to UBS AG cut forecasts for global growth and predicted interest rates will stay on hold until at least 2013.     

Citigroup said the world economy will grow 3.8 percent this year and 4 percent in 2012 in purchasing power parity terms, down from 4.2 percent and 4.4 percent. UBS cut its estimate for expansion next year to 3.3 percent from 3.8 percent and Societe Generale SA pared its forecast to 3.9 percent from 4.6 percent.     

The worsening economic outlook provides the context for three days of talks in the Wyoming resort featuring officials including Federal Reserve Chairman Ben S. Bernanke and European Central Bank President Jean-Claude Trichet. While global recession will be avoided, weak growth will force the Fed, ECB and Bank of Japan to leave borrowing costs unchanged through at least next year, Citigroup, Societe Generale and UBS said.