Cheng “Charlie” Saephan wore a broad smile and a bright blue sash emblazoned with the words “Iu-Mien USA” as he hoisted an oversized check for $1.3 billion above his head. The 46-year-old immigrant's luck in winning an enormous Powerball jackpot in Oregon earlier this month — a lump sum payment of $422 million after taxes, which he and his wife will split with a friend — has changed his life. It also raised awareness about Iu Mien people, a southeast Asian ethnic group with origins in China, many of whose members fled from Laos to Thailand and then settled in the U.S. following the Vietnam War.