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Novel mechanism to avoid theoretical bound on kaon rare decays Researchers try to revisit a theoretical bound, which is based on symmetries, between the charged and neutral kaon rare decays into the pion and neutrinos. Last September, KOTO experiment searching for neutral kaon rare decay reported events with an unexpected rate, which is much bigger than the standard model predictions. So far, KOTO experiment has not claimed that these events are the rare kaon decay signals. On the other hand, …


  A research group including Associate Professor Kazuhiro Nakazawa, of the Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University, detected a downward burst of gamma rays during lightning discharge with scintillation detectors at the Kashiwazaki-Kariwa Nuclear Power Station at sea level in Japan. This research was published in Physical Review Letters on August 7, 2019.   Although lightning is a familiar natural phenomenon, thunderclouds still hold many mysteries. Terrestrial gamma ray flashes (TGFs), which are …


A research group including Associate Professor Kazuhiro Nakazawa, KMI, Nagoya University has observed high-energy radiation phenomena coming from thunder-clouds, and found a prolonged steady emission resulted in a short burst of radiation associated with a lightning discharge. The evolution of the phenomena strongly suggests the initial long emission is related with the triggering of the lightning. The research group was performing ground-based gamma-ray observation campaign aiming at winter thunder-clouds in Hokuriku-region. In the work, they observed a minute-long radiation from …


“Neutron is a massive and chargeless particle, which can be used for various precision measurements”, Associate Professor Masaaki Kitaguchi of KMI says. “We have successfully developed a new type of position sensitive detector with extremely-high resolution of 11 nm. It can be a strong tool for experiments with neutrons.” Nuclear emulsion is used for various experiments for particle physics with muons and neutrinos, which is also applied to imaging through a pyramid today. Nagoya University team is continuing to develop …


  On March 11th, 2019, Phase 3 operation of the SuperKEKB/Belle II project began successfully, marking a major milestone in the development of Japan’s leading particle collider. This phase will be the physics run of the project, in which the Belle II experiment will start taking data with a fully instrumented detector. The KEKB accelerator, operated from 1999 to 2010, currently holds the world record luminosity for an electron-positron collider. SuperKEKB, its successor, plans to reach a luminosity 40 times …


Using the powerful Japanese Subaru telescope, the Hyper Suprime-Cam (HSC) survey collaboration team has made and analyzed the deepest wide field map of the three-dimensional distribution of matter in the Universe. The reserach team, including researchers from Nagoya University, Professor Naoshi Sugiyama at KMI/Graduate School of Science, Lecturer Atsushi Nishizawa and Assistant Professor Hironao Miyatake at Institute for Advanced Research, has used the gravitational distortion of images of about 10 million galaxies to make a precise measurement of the lumpiness …


Particle physicists at Nagoya University were very excited watching the memorial event of the new international experimental project, the Belle II experiment using the SuperKEKB electron-positron collider at the KEK laboratory in Japan. On April 26 at 0:38 JST, 2018, the electron and position beams collided each other for the first time, and the particle reaction made by the collision was recorded by the Belle II particle detector. This is one of the greatest milestones of the project. The excitement …