Stocks closed lower Tuesday as traders awaited corporate profit reports. Alcoa posted its results after the close in the unofficial kickoff to weeks of earnings announcements. The reports will be ‘the big driver for the next couple of weeks,’ said Kim Caughey Forrest, at Fort Pitt Capital. Europe’s debt crisis continued to cast a pall; unemployment in the 17 countries that use the euro hit a new high of 11.8% in November, leading the European Union to warn about the risk of fraying social welfare systems in southern Europe. Trading has been cautious in the week since Congress and the White House struck a deal to avoid the fiscal cliff.