How big an impact did Charles Mingus have beyond the jazz world? And why are so many stylistically disparate artists drawn to the music of the legendary composer, bassist and band leader, who died in 1979 and whose centennial will be celebrated on Saturday in Nogales, the Arizona border town where he was born? These are questions we have posed to an array of performers in Union-Tribune interviews over the years. Here are some of their responses. Rolling Stones guitarist Keith Richards: “Charlie Mingus was one of the most original composers and players of (the 20th) century. I got turned on to …