In string theory, D-branes are a class of extended objects upon which open strings can end with Dirichlet boundary conditions, after which they are named, D-branes were discovered by Dai, Leigh and which American theoretical physicist, and string theorist?
D-brane:  D-branes were discovered by Dai, Leigh and Polchinski, and independently by Hořava in 1989. Joseph Polchinski: Joseph Polchinski (born May 16, 1954) is an American theoretical physicist and string theorist.
Joseph Polchinski