2D moblie game raycast problem

Hey guys, I am trying to shoot a raycast2D at the position of my finger, when I touch the screen on my android tablet. I then want it to destroy the gameobject if it is tagged bad guy and add to the players score, however it doesn't work.

my code

     void  Update(){
         if(Input.touchCount >0){
             foreach (Touch touch in Input.touches){
                 Vector2 dir = Vector2.zero;
                 Vector3 touchworldpos =Camera.main.ScreenToWorldPoint(touch.position);
                 Vector2 touchpos2d = new Vector2(touch.position.x,touch.position.y);
                 Debug.Log(touchpos2d);
                 RaycastHit2D hit = Physics2D.Raycast(touchpos2d,dir);
                 Debug.DrawRay(touchpos2d,dir,Color.blue);
                 if(hit!=null&&hit.collider!=null){
                     if(hit.collider.tag ==" bad guy"){
                     Destroy (hit.collider.gameObject);
                     die.Play(); 
                     
                     Addscore.AddScore();
                     player.transform.localScale+=new Vector3(0.1f,0.1f);
                     
 
                 }
                 
             }
         }
     }
     }