Three years after changing their stadium name to Ameriquest Field, the Rangers severed a 30-year naming rights deal Monday with struggling lender Ameriquest Mortgage Co. and rebranded their home field as Rangers Ballpark in Arlington. The new name is almost identical to The Ballpark in Arlington, the stadium's name before the reported $75 million sponsorship with Ameriquest was announced in 2004. The parent company of the subprime lender, ACC Capital Holdings Corp., announced last week that it was slashing its work force for the second time in less than a year. The company cited the "very challenging nonprime market" for the cuts.