JACKSON HOLE, Wyo. (Reuters) – Central bankers in charge of the vast bulk of the world’s economy delved deep into the weeds of money markets and interest rates over a three-day conference here, and emerged with a common plea to their colleagues in the rest of government: please help. Mired in a world of low growth, low inflation and low interest rates, officials from the Federal Reserve, Bank of Japan and the European Central Bank said their efforts to bolster the economy through monetary policy may falter unless elected leaders stepped forward with bold measures. These would range from immigration reform in Japan to structural changes to boost productivity and growth in the U.S. and Europe. Without that, they said, it would be hard to convince markets and households that things will get better, and encourage the shift in mood many economists feel are needed to improve economic performance worldwide. During a Saturday session at the symposium, such a slump in expectations about inflation and about other aspects of the economy was cited as a central problem complicating central banks’ efforts to reach inflation targets and dimming prospects in Japan and Europe.