Rihanna unveiled her new single "Only Girl (In the World)" on Tuesday shortly after announcing the title of her fifth studio album, "Loud," on her official fansite.

Rihanna's "Loud" album (Def Jam/Universal) achieved its first week at No. 1 on the U.K.'s first sales charts of 2011, as Matt Cardle's "When We Collide" (Syco Music/Sony Music Entertainment) began ...