Music historian Jeffrey Engel, of West Cornwall, will present a Live Zoom lecture through the Bloomfield Public Library. Verdi’s “Ballo” is about the assassination of a Head of State. This is no laughing matter. Nevertheless, the opera is sprinkled with characters getting the giggles and the chuckles. Jeffrey Engel will detail the background of “Un Ballo in Maschera,” play musical highlights, and explain why laughter plays a part in such a dark subject.