In this thesis we give, a brief review on noncommutative space – time (NCST) and QCD sum rule. Then we study the noncommutative (NC) effects on semileptonic transition of with three point QCD sum rule (3PSR). B meson is pseudoscalar with quark content and is vector with quark content In this transition b quark transform to c quark. The transitition amplitude consists of two parts; leptonic and hadronic parts. We know, the quarks are not free, so to describe hadronic part in ordinary space – time, four form factors are needed. To obtain the form factors, we use 3PSR method along with the noncommutative effects. For this purpose we replace the ordinary weak vertices in the transition amplitude with the NC counterpart. since is Lorentz quantity more new form factors are needed to describe the transitition amplitude in NCST. furthermore new scalars such a , appear in the theory. therefore even at the zero momentum transform, the form factors can depend on the momentum of the incoming and outgoing particles. We calculate the different branching ratios for the B meson decay in the NCST and show that the NC corrections up to the first order of is zero. We find the NC correction up to second order of and compare the obtained results with the experimental value for B decay. As a first study on the B decay in the NCST we find, the bound on the in the order of 3.82 GeV i for ( ) = . Keywords: Semileptonic Transition, Noncommutative space – time, Form Factor, transition amplitude
