High Energy Physics in Japan in 1970’s

H.Sugawara, Kona,Hawaii,2010

High Enrgy Physics in 1970’s was dominated by US

B.Richter etal. １９７４

L. Lederman etal. 1977

Executive Summary The KEK 12 GeV Proton Synchrotron (PS) Program since 1976: Since its commissioning in 1976, the 12 GeV PS at KEK has successfully supported a highly productive physics program in Japan. For more than 25 years, the PS has operated well with good reliability in spite of the constraint of having limited aperture. This limited aperture has prevented the PS from taking advantage of the steadily increased booster intensity over the years. With many innovative steps the 12 GeV PS operations group recently succeeded in increasing the average intensity for the fast extraction from 4x1012 ppp to 6x1012 ppp, the improvement that was essential for the successful run of the K2K experiment. The experimental program of the 12 GeV PS can be divided into three periods, namely 1977 - 1984 (before TRISTAN), 1985 - 1998 (after the start of TRISTAN and before K2K), and the period since 1999 (after the start of the K2K experiment). During the first period, the PS was the only high-energy accelerator in Japan, and as such, it had supported a wide range of particle and nuclear physics experiments. Notable accomplishments in this period are an early determination of the upper limit for K+→π+νν-bar and the rejection of the existence of barionium states.

In theoretical particle physics Japanese researchers were quite active and were playing some leading role.

Examples

1. Kobayashi-Maskawa, 1973

Nagoya group was flexible about the number of quarks because of the

signal of “new quark” in the cosmic ray experiment done by Niu.

2. Supersymmetry

　　　　　　　　 H.Miyazawa, 1968 (Miyzawa and H.S. 1965)

３ .Proton decay

　　　 Yoshimura 1978

４ .MNS

　　 Maki-Nakagawa-Sakata, 1962

５． Color degrees of freedom etc.

　　　　　　　　　 Nambu (still a Japanese in 1970’s)

The role played by US-Japan collaboration in high energy physics

--early 1980’s—

From the report of evaluation committee of 1986

members:Sachio Hayakawa (chair),Tomoo Ishihara, Hirotaka Sugawara

Yoshio Yamaguchi, Toshimitu yamazaki

1. The only high energy facilities available for Japanese researchers of this field

inside Japan at the starting time of this project were 1.3Gev electron synchrotron in INS and 12 GeV proton synchrotron 　 in KEK. The handicap of Japanese researchers using high energy accelerators especially the colliding machines was taken into account when we evaluate the project.

2. The committee also considered the influence of TRISTAN project which was

started soon after this project was begun. The manpower anticipated by those who participated in US-Japan project was partly transferred to TRISTAN. But also we realized that the experience learned in US-Japan project was useful in TRISTAN.

Generic evaluation

The annual budget of 15 oku-yen Is as large as 　 one “tokokutei kenkyu”.

But the number of participating groups is about 1/10 of regular “tokutei kenkyu”. The travel money spent is comparable to the entire travel budget of

Science Council of Japan (Gakujutsu kaigi). This shows that the project is far better financed than other projects. This is because the project is the largest international collaboration that Japan ever experienced in the field of basic science .

Some may expect, therefore, the project should produce the best possible result both in the scientific outputs and also in the leadership of Japanese scientists.However, considering the smallness of Japanese budget compared to the large investment by US in the construction and in the operation of accelerators, we may not expect the best outputs. We found, however, most of the experiments accumulated reliable data and contributed much to the development of physics.

The committee recognizes that the process footprinted by this project is a necessary step for Japan to become a developed country in the field of high energy physics.The committee also realizes that Japanese researchers learned great lessons which are useful in the TRISTAN project, trained inan international atmosphere, understanding different life and culture.From generic view point, the committee highly appreciate this project but nevertheless it is obliged to criticize the following:Although we understand the handicap of Japanese researchers,speaking foreign language and living in a different life style, we stillpoint out that only few researchers are playing a leading role in theexperiments.

Conclusion

US-Japan collaboration in high energy physics from the end of 1970’s to the early 1980’s played a very important role especially for those in Japanese universities partly because the period overlaps the construction stage of KEK.