Washington(Reuters)=US Federal Reserve officials have slashed interest rates half a percentage point because of the coronavirus They may keep that lower rate in place even if the risks to the economy from the virus pass in order to test just weak US inflation has become and to encourage what some policy makers have termed "opportunistic reflation"- a change of set events that might help the Fed hit long-missed 2 percent target for the pace of annual price increase.In this case a rate cut no one anticipated in a response to a confidence-rattling global health emergency could, a..........