After a long pursuit of the mysterious elementary particles that shower Earth, Takaaki Kajita won the Nobel Prize in Physics on Tuesday for his discovery of neutrino oscillations that proves the neutrinos have mass. It was the second consecutive year that a Japanese researcher won the physics prize.
Overcoming accidents at research facilities in the past, Kajita, 56-year-old director of the University of Tokyo's Institute for Cosmic Ray Research (ICRR), worked together with his senior researcher Yoji Totsuka, a distinguished professor emeritus at the university who died seven years ago and would have possibly become a corecipient of the prize with Kajita if he was still alive.
"I couldn't have done this on my own," Kajita said as he repeatedly thanked his teachers and colleagues.
At about 8:40 p.m. on Tuesday, Kajita appeared at a press conference in the university's Hongo Campus in Bunkyo Ward, Tokyo, donning a dark gray suit with a light blue tie.
He received a congratulatory call from Prime Minister Shinzo Abe and repeatedly thanked him before sitting down.
"I feel really honoured. My mind is completely blank, and I can't say anything more than that for now," Kajita said. "I'm sorry, but that's all I have to say."
"All I've been doing is research. I think the biggest support was from [my wife], who patiently allowed me to do that," Kajita said.
When asked about his personal motto, Kajita said, "I don't have anything cool to say, but just 'thank you, neutrinos.'"
His comment prompted laughter from the media for a remark similar to that of Satoshi Omura, who won the Nobel Prize in Physiology or Medicine the previous day. Omura told the press, "It was all thanks to bacteria."
In Hida, Gifu Prefecture, staff members of ICRR's Kamioka Observatory were raving about Kajita's award. The observatory houses a particle detector called Super-Kamiokande, which helped confirm his discovery.
Observatory chief Prof. Masayuki Nakahata told reporters Tuesday night he believed the Super-Kamiokande would achieve many other advances in the future.
"We'll continue observing space to investigate the mysteries of elementary particles," Nakahata said.
Laureate Koshiba 'happy'
"Mr. Koshiba was the first person I told," Kajita said. "This discovery was made possible by Mr. Totsuka's achievement."
He referred to his two mentors - 2002 Nobel Prize winner Masatoshi Koshiba, an 89-year-old distinguished professor emeritus at the university, and the late Yoji Totsuka.
The discovery of neutrino oscillations began with Koshiba's study, later handed down to Totsuka who was a major candidate of a Nobel Prize winner before ending up in Kajita's hands.
The possibility of neutrino oscillations had grown into a major discovery thanks to Super-Kamiokande research led by Totsuka, who used to call himself a "drill sergeant."
In November 2001, research efforts were threatened after many of Super-Kamiokande's observation instruments broke down. Totsuka acted fast and promised the world the system would be rebuilt, which inspired Kajita who was analysing data at the time. True to Totsuka's word, the system was back online a year later.
Even though Totsuka was diagnosed in 2000 with bowel cancer, he continued to lead responses to the accident. In July 2008, he died at 66.
Asked during Tuesday's press conference if Totsuka would have been named as a corecipient of the prize, Kajita quickly replied, "Absolutely, I believe so."
Koshiba was interviewed on Tuesday night at his house in Tokyo's Suginami Ward, in which he said his dream was that "his students would receive the Nobel Prize" after him.
"I believed that day would come, and it did. I'm happy," Koshiba said with a smile.