Sharif Digital Repository

Jets originating from bottom (b) quarks, play an important role in the study of Standard Model processes together with the search for new physics. In the CMS experiment a considerable e?ort is dedicated to the development and the performance study of so-called b-tagging algorithms. On the other hand, the top quark which is produced in pair (tt¯) with a high rate at the LHC, decays near 99% of the time to a b-quark. Hence it provides a rich source of b-quark jets, suitable for b-jet identi?cation studies. In this thesis, a fully data-driven method to measure the b-tagging e?ciency, using top quark events in its semi-electron ?nal state, is developed. The results of the application of the... 

Resent advances in ultra-intense short-pulse lasers and their numerous applications stimulated the research activities in important fields such as generation of high-energy electron and ion beams, monoenergetic electron beam, monoenergetic ion beam, X-ray emission, terahertz radiation, high harmonic and attosecond pulses generation. In all above mentioned applications the relativistic electrons behavior especially the electron density distribution and the velocity of electrons play an important role.
Investigating the behavior of relativistic electrons which are generated in the interaction of high power femtosecond lasers with plasma and their related applications is the main purpose... 

A highly reliable tool for transient simulation is vital in the safety analysis of a nuclear reactor. Despite this fact most tools still use diffusion theory and point-kinetics that involve many approximations such as discretization in space, energy, angle and time. However, Monte Carlo method inherently overcomes these restrictions and provides an appropriate foundation to accurately calculate the parameters of a reactor. For this reason, in this thesis, a dynamic Monte Carlo code named MCSP (Monte Carlo dynamic Simulation of Particles tracking) is developed for both the steady state and time-dependent simulation of particle (neutrons, photons and electrons) tracking in an arbitrary 3D...