By Ankika Biswas and Johann M Cherian (Reuters) – U.S. stock indexes fell sharply on Thursday, with the Dow on track for its steepest single-day fall in three months, as the Federal Reserve’s guidance for protracted policy tightening quelled hopes of the rate-hike cycle ending anytime soon. The benchmark S&P 500 and tech-heavy Nasdaq were also set to notch their worst single-day performance in six weeks. The U.S. central bank hiked rates by 50 basis points on Wednesday, slowing down from four back-to-back 75 bps hikes, although Fed Chair Jerome Powell said recent signs of weakening inflation h…