player A passes the ball to his teammate, who doesn't see the pass coming.

can player A then regain possession without anyone having touched the ball ?

and if yes, can he dribble ?

if the player has not used a dribble and the ball hits the floor first they may recover but may not dribble again.

if the player has already used a dribble and recovers after the ball has hit the floor it would be an illegal dribble

if the player has/has not already used a dribble and recovers before the ball has hit the floor it would be a traveling violation.