CLAS12 and its initial Science Program at the Jefferson Lab Upgrade

An overview of the CLAS12 detector is presented and the initial physics program after the energy-doubling of the Jefferson Lab electron accelerator. Construction of the 12 GeV upgrade project has started October 2008. A broad program has been developed to map the nucleon’s 3-dimensional spin and flavor content through the measurement of deeply exclusive and semi-inclusive processes. Other programs include forward distribution function to large $x_{B} \le 0.85$ and of the quark and gluon polarized distribution functions, as well as nucleon ground state and transition form factors at high $Q^2$. The 12 GeV electron beam and the large acceptance of CLAS12 are also well suited to explore hadronization properties using the nucleus as a laboratory