US STOCKS-Wall Street weighed down by energy stocks

* Tyco jumps after deal to merge with Johnson Controls(NYSE: JCI – news)
* Caterpillar (NYSE: CAT – news) falls after Goldman slaps with “sell” rating
* Twitter (Xetra: A1W6XZ – news) down, 4 top executives to leave co
* Indexes down: Dow 0.47 pct, S&P 0.69 pct, Nasdaq (NasdaqGS: NDAQ – news) 0.63 pct (Updates to late afternoon)
By Lewis Krauskopf
Jan 25 (Reuters) – Wall Street stumbled on Monday after itsfirst positive week of 2016, pulled lower by