The Dow Jones Industrial Average soared deeper into record terrain on Thursday as investors pinned their hopes on a peace deal in Iran .  The blue-chip index surged 877 points in afternoon trading, or 1.7%, to 51,564. The broader S&P 500 and Nasdaq Composite Index saw more modest gains, rising 0.5% and 0.2%, respectively.  Stocks have notched a succession of record highs in recent weeks, with Wall Street investors betting that the U.S. and Iran are nearing an agreement to end the war.  Those