Measurement of the gravitational form factors at J-PARC

The Japan Proton Accelerator Research Complex, J-PARC, is a high-intensity proton accelerator facility, with the Materials and Life science Facility, the Neutrino Experimental Facility, and the Hadron Experimental Facility. The Hadron Experimental Facility utilizes the 30-GeV proton beams from the accelerator. The intense 30-GeV proton beams are injected into the production target, and the secondary beams, such as kaons, pions. Currently, strangeness nuclear physics experiments are a major activity with the low momentum (1 - 2 GeV/c) charged kaons and pions. Neutral kaons are used for a Kaon rare decay experiment. Alternatively, 8-GeV proton beams are used for a muon-to-electron conversion experiment. In addition, there is a high-momentum beamline, which is used for low-intensity 30-GeV proton beam experiments. There is an idea to upgrade this high-momentum beam line for high-momentum secondary beams. Once 10 or 20 GeV/c pions become available, physics cases will be greatly expanded. An experiment has been proposed to use these high-momentum pion beams to carry out charmed baryon spectroscopy. In the experiment, high-momentum negative pions will be used to pruduce charmed baryons with (pi, D^(*-)) reactions. A large acceptance spectrometer to detect D^(*-) will be constructed. In addition, a Letter of Intent has been submitted, which intend to investigate generalized parton distributions and pion distribution functions with the exclusive pion-induced Drell-Yan process. This LoI proposes an addition of detectors to the spectrometer used for the charmed baryon spectroscopy. This kind of studies will lead to an understanding of gravitational form factors.