Primary proton beam line at the J-PARC hadron experimental facility

A brief description of the primary beam line at the hadron experimental facility at the Japan Proton Accelerator Research Complex (J-PARC) is presented. The facility has been constructed in Tokai, Japan, and the first beam was successfully introduced into the experimental hall in January 2009. The facility utilizes a high-intensity proton beam with an energy of 50 GeV and a power of 750 kW and provides various secondary beams such as pions, kaons, and antiprotons for nuclear and particle physics experiments. We have developed beam-line components with sufficient radiation hardness and heat resistance to handle the high-power proton beam. (author)