From the precise measurements in recent days, it has been revealed that there are significant amount of unknown material in our Universe. The material cannot explained by the current particle physics. The amount of the unknown material comparing to the normal material is about 5-6 times.
Since such unknown material doesn’t emit light, it is called “Dark Matter”.
At present, although most of researchers believe there is dark matter in our Universe, the observational evidences of dark matter so far are indirectly obtained only through gravitational interactions. Since dark matter should also exist around us, if we could observe dark matter directly via other interaction other than gravity in our laboratory, it will be a strong clue to reveal the nature of the dark matter. It will also deepen our understanding of Universe and particle physics. Though direct search of dark matter has been actively carried out in the world from around 1990, convincing evidence of dark matter has not been obtained yet.
Currently, in our Particle Physics group, we have been promoting two direct dark matter search experiments; XMASS and NEWAGE. XMASS uses about 1-ton of purified liquid xenon, which is current largest amount of xenon in the direct dark matter search projects in the world. In our laboratory, we are aiming to detect the world's first signs of dark matter in XMASS. NEWAGE is trying to detect the arrival direction of the dark matter by using a direction sensitive detector . Our laboratory is leading the NEWAGE experiment. Currently, R&D of the NEWAGE detector and test observations are on going.
If we could observe the initial signs of dark matter by XMASS and then the arrival direction of dark matter could be determined by NEWAGE, the discovery of dark matter would be more robust and a significant progress is expected in our understandings of the Universe and particle physics.