Director of the ICRR Awarded Nobel Prize

Takaaki Kajita

Takaaki Kajita, Director of the Institute for Cosmic Ray Research at the University of Tokyo has been awarded the Nobel Prize in Physics for his work with neutrinos, along with Arthur McDonald from Queen's University in Canada.  Their research was able to show that neutrinos, incredibly small subatomic particles with no electric charge, actually had mass, contrary to many long-standing assumptions.

In order to demonstrate that neutrinos did indeed have mass, Kajita and his fellow researchers constructed two separate detectors deep underground.  By placing the detectors beneath over a kilometer of solid rock, they were able to block out other particles that could interfere with their readings.  One was built beneath a mountain in Gifu prefecture, while the other was set up in an old nickel mine in Ontario.  By detecting changes in the neutrinos as they passed through the earth and its atmosphere, the scientists were able to prove that the particles had mass.

Neutrinos are created by a number of different phenomena in the universe, including cosmic rays.  Kajita's team first discovered the changes in neutrinos while observing cosmic rays in 1998.  Continuing their research, the ICRR is one of the collaborators in the Telescope Array Project.

By revealing new information about neutrinos, Kajita and McDonald's work has dramatically changed out understanding of the fundamental particles that make up the universe.  It has also shed new light on physics problems like solar neutrinos that have baffled scientists for decades.  Their discoveries have the potential to open up whole new fields of research that could have practical applications for topics like nuclear fusion and astronomy.