Abstarct: Quark gluon plasma (QGP) is a new phase of matter which includes of quarks and gluons that are asymptotically free. This novel phase is created by collisions of relativistic heavy ions like gold and lead in RHIC and LHC. By creating of this novel phase in colliders, this hope has come about that new details of Quantum Chromo Dynamics (QCD) could be studied exactly. In this thesis physics of jets which are created in QGP medium, is studied. Jets are created in QCD by collisions of protons. So it is expected that in collisions of relativistic heavy ions, these jets are created, too. However because of existence of QGP their behavior is different. The existence of this plasma causes jets to melt after traveling some distances and makes them to disappear. This quantity called ”Stopping distance” . It is not possible to use perturbation methods to study physics of these jets, as the coupling constant in this medium is strong. So, Anti-de Sitter/conformal field theory (AdS/CFT) is used. In one side of correspondence there is anti-de Sitter (AdS) and on the other side there are conformal field theories(CFT) which are related to Yang-mills quantum field theories and supersymmetries. In this thesis, the AdS/CFT is used as a tool to study the jets. First the problem of jets is considered in zero temperature and without considering of plasma. The dual of this problem is AdS space-time. Then the temperature is included. In this case, the effect of tempreture is studied by considering of a blackhole in AdS spacetime . So here stopping distance means falling of string into the event horizon of black hole. In this thesis we introduce jets as an open string which is falling. The action of this string and also the equation of motion is studied. Then the equation of motion is solved by numerical methods. We show that on the falling string, there will not create any event horizon. We get more real values for coupling constant by introducing gravitational square corrections. This is known as Gauss-Bonnet constant. It is illustrated that by considering of these corrections the stopping distance decreases