But sources told the New York Post that "a beautiful New York waitress" named Karizma Ramirez could be partly responsible for the breakup.
"They also spent Easter Sunday together," a source told the paper.
TMZ also says Rihanna celebrated her newfound singledom by smoking either a cigar or a joint at Greystone Manor nightclub in Hollywood.
"Sources inside Greystone Manor nightclub tell us, Rihanna arrived around 1am with her assistant and security guard ... and pretty much kept to herself. She left an hour or so later."
Meanwhile, Brown is due back in court June 10 on charges that the 23-year-old singer lied about completing his community service, part of his punishment for his 2009 assault on Rihanna.