The present Report concerns the current status of the Tau/Charm accelerator project and in particular discusses the issues related to the lattice design, to the accelerators systems and to the associated conventional facilities. The project aims at realizing a variable energy flavor factory between 1 and 4.6 GeV in the center of mass, and succeds to the SuperB project from which it heritates most of the solutions proposed in this document. The work comes from a cooperation involving the LNF accelerator experts, the young newcomers, mostly engineers, of the Cabibbo Lab consortium and key collaborators from external laboratories. The result of this effort is impressive, given the little time elapsed since SuperB cancellation, and is due to the enthusiasm of its contributors as well as to the deep and reusable work done for the parent project SuperB, showing the knowledge accumulated in accelerator physics at LNF. In the last section a possible time scale for the construction, as well as the financial load and the personnel requests, are preliminary outlined. Detector design and specific Physics channels to be studied by such an accelerator will be addressed in a separate document, ready by the end of September. The current work on these topics is concentrating in re-adapting the BaBar detector to a symmetric machine and to more stringent particle identification requirements. The physics case is robust and specific with a few discovery channels, but detector simulations are needed to assess the final potential of the experiment. A Tau/Charm Factory can provide multiple returns. An immediate economic one, related to the job opportunities of its construction and operation, and to the average presence on the territory of hundreds of physicists, engineers and technicians, most of them from an international community. The preparation to international tenders for its realization will make the Italian industries more competitive in future tenders of accelerator based infrastructures, including those related to medical physics or light sources. The attraction of young researcher abroad will generate a 'brain catch' program. The project will strongly contribute to the HORIZON 2020 program of excellent science through the development of skills and talents. It will be an incubator of future emerging technologies, anticipated and tested in the High Energy Physics environment (electronics, engineering, web, computing). In particular, detector performances require the development of high technology in 3D electronics devices for the integration of sensors (particle trackers), today one of the major trends in the emerging industrial technologies. Sophisticated software codes are needed to simulate and treat the huge amount of data coming for the experiment, calling for a powerful computational network based on GRID technology. The novel control system developed for the accelerator can be exported to the industrial world. On the accelerator side, very low emittance rings, such as in Tau/Charm project, will generate skills useful in the development of future linear colliders Damping Rings. The capability for Italy to host an International laboratory, the Cabibbo Lab, may activate a co-funding process from European countries in a reciprocity scenario with respect to the Italian contributions to major European infrastructures. Besides a frontier particles detector and collider, the infrastructure aims to host a Free Electron Laser (FEL) facility with Angstrom class resolution, for state of the art material and biophysics studies, and a test area where extracted beam of various type will be available, ensuring to the facility a long exploitation time. As described briefly at the end of this document, key applications will then be made available for a wider scientific and industrial community.
M.E. et al. (Wed,) studied this question.