The new European Central bank (ECB) headquarters are pictured in FrankfurtGlobal central bankers, eager to see the economy stand on its own feet, faced the rude reality this week of market turmoil threatening already faltering growth and prolonging world reliance on easy money. Stocks slumped again on Wednesday pushing S&P 500 losses to almost 8 percent since mid-September. The dollar fell and U.S. bond prices soared after weak Chinese inflation and U.S. producer price and retail sales data fanned fears the world economy could be even weaker than thought. When stock markets turned south last week after rallying for much of this year, many policymakers initially played that down. In fact, the sell-off could be seen bringing some healthy volatility back to markets that officials worried had become too complacent to risks ranging from tensions surrounding the conflict in Ukraine to the Ebola outbreak. But the deepening of the sell-off may have put major central banks on their heels, by raising the prospect of the market rout going too far too fast, threatening to hurt confidence and potentially triggering a pullback in spending. More