is a Japanese
theoretical physicist working in particle physics. Koide is famous for his eponymous
Koide formula
The Koide formula is an unexplained Empirical relationship, empirical equation discovered by Yoshio Koide in 1981. In its original form, it relates the masses of the three charged leptons; later authors have extended the relation to neutrinos, qua ...
, which some physicists think has great importance but which other physicists contend is merely a
numerical coincidence.
Early life and education
Koide earned in 1967 a B.Sc. with major in physics and in 1967 a M.Sc. in Theoretical Elementary Particle Physics from
Kanazawa University
Kanazawa University ( ja, 金沢大学, Kanazawa Daigaku, abbreviated to ja, 金大, Kindai) is a Japanese national university in the city of Kanazawa, the capital of Ishikawa Prefecture. Founded in 1862, it was chartered as a university in 194 ...
. In 1970, he received his Doctor of Science degree from
Hiroshima University
is a Japanese national university located in Higashihiroshima and Hiroshima, Japan. Established in 1929, it was chartered as a university in 1949 following the merge of a number of national educational institutions.
History
Under the Nationa ...
with a thesis “On the Two-Body Bound State Problem of Dirac Particles”.
Career
After working as a
postdoc
A postdoctoral fellow, postdoctoral researcher, or simply postdoc, is a person professionally conducting research after the completion of their doctoral studies (typically a PhD). The ultimate goal of a postdoctoral research position is to p ...
in the physics department of Hiroshima University and then a postdoc in the applied mathematics department of
Osaka University
, abbreviated as , is a public research university located in Osaka Prefecture, Japan. It is one of Japan's former Imperial Universities and a Designated National University listed as a "Top Type" university in the Top Global University Project. ...
, he became, from 1972 to 1973, a Lecturer in the School of Science and Engineering,
Kinki University, Osaka. Koide was Assistant Professor (1973-1977) then Associate Professor (1977-1987) of General Education, Shizuoka Women's University,
Shizuoka
Shizuoka can refer to:
* Shizuoka Prefecture, a Japanese prefecture
* Shizuoka (city), the capital city of Shizuoka Prefecture
* Shizuoka Airport
* Shizuoka Domain, the name from 1868 to 1871 for Sunpu Domain, a predecessor of Shizuoka Prefecture
...
. From April 1987 to March 2007 he was a Professor of Physics at
University of Shizuoka
The , is a public university in Shizuoka City, Shizuoka Prefecture, Japan.
Overview
The University of Shizuoka was created through the amalgamation of three former public universities in 1987 and was expanded to comprise five colleges. These ...
, Shizuoka and then retired as professor emeritus. In 1986 he was a visiting professor at the
University of Maryland and in 2002 a visiting researcher at
CERN
The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Gene ...
. Koide was from April 2007 to March 2009, a guest professor at Research Institute for Higher Education and Practice,
Osaka University
, abbreviated as , is a public research university located in Osaka Prefecture, Japan. It is one of Japan's former Imperial Universities and a Designated National University listed as a "Top Type" university in the Top Global University Project. ...
, then from April 2009 to March 2011 a guest professor and from April 2011 a guest researcher at Osaka University, and from April 2010 a professor, Department of Maskawa Institute,
Kyoto Sangyo University
is a private university in Kyoto, Japan.
History
The university was established in 1965. The founder was Toshima Araki (, 1897–1978), and Hideo Iwakuro (岩畔 豪雄 Iwakuro Hideo, 10 October 1897 – 22 November 1970), the Japanese spy ...
,
Kyoto.
Contributions to physics
In the composite model of
mesons, Koide's thesis demonstrated that a mass
of a composite particle which consists of the rest masses
cannot be lighter than
except for the case
when J
P is not = 0
-. This offered a severe problem for the quark model. (Koide’s work was done before the establishment of
QCD
In theoretical physics, quantum chromodynamics (QCD) is the theory of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type o ...
.)
Katuya and Koide predicted that lifetimes of D
± and D
0 should be considerably different from what was at that time the conventional anticipation tau(D
±)= tau(D
0). Their prediction of these lifetimes was the first in the world prior to the experimental observation.
He published the famous
Koide formula
The Koide formula is an unexplained Empirical relationship, empirical equation discovered by Yoshio Koide in 1981. In its original form, it relates the masses of the three charged leptons; later authors have extended the relation to neutrinos, qua ...
in 1982 with a different presentation in 1983.
Originally, Koide's proposed charged
lepton
In particle physics, a lepton is an elementary particle of half-integer spin ( spin ) that does not undergo strong interactions. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutr ...
mass formula was based on a composite model of
quark
A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All commonly o ...
s and leptons. In a 1990 paper, from the standpoint that the charged leptons are elementary, by introducing a scalar
boson with (octet + singlet) of a family symmetry U(3), Koide re-derived the charged lepton mass formula from minimizing conditions for the scalar potential.
In 2009, he related the
neutrino mixing matrix to the up-quark mass matrix. Koide and Hiroyuki Nishiura have published articles on a quark and lepton mass matrix model and a neutrino mass matrix model.
References
External links
physics papers by Y. Koide available on arxiv.orgScientific publications of Yoshio Koideon
INSPIRE-HEP INSPIRE-HEP is an open access digital library for the field of high energy physics (HEP). It is the successor of the Stanford Physics Information Retrieval System (SPIRES) database, the main literature database for high energy physics since the 1970 ...
{{DEFAULTSORT:Koide, Yoshio
Japanese physicists
Theoretical physicists
1942 births
Living people
People from Kanazawa, Ishikawa
Hiroshima University alumni
People associated with CERN
Kanazawa University alumni