James Bjorken

James Daniel "BJ" Bjorken (born 1934) is an American

He was awarded the Dirac Medal of the ICTP in 2004; and, in 2015, the Wolf Prize in Physics and the EPS High Energy and Particle Physics Prize.^[3]

Early life and education

James Bjorken's father, J. Daniel Bjorken, was an immigrant from Sweden near

At MIT, he quickly decided to major in physics; one of the main reasons was his enjoyment of the lectures that Hans Mueller gave. Another of his influences at MIT was Sidney Drell, who became his mentor. After graduating in 1956, he attended Stanford University, graduating with his PhD in 1959 and staying on as a postdoctoral researcher for several years.^[4]

Work

Bjorken discovered in 1968 what is known as

This observation was critical to the recognition of quarks as actual elementary particles (rather than just convenient theoretical constructs), and led to the theory of strong interactions known as quantum chromodynamics, where it was understood in terms of the asymptotic freedom property. In Bjorken's picture, the quarks become point-like, observable objects at very short distances (high energies), shorter than the size of the hadrons.

Bjorken also discovered the Bjorken

. Specially: ${\displaystyle \int _{0}^{1}dx(g_{1}^{p}(x)-g_{1}^{n}(x))=g_{A}/6}$, where ${\displaystyle x}$ is the Bjorken scaling variable, ${\displaystyle g_{1}^{p(n)}(x)}$ is the first spin

${\displaystyle g_{A}}$

Bjorken was also among the first to point out to the phenomena of jet quenching in heavy ion collisions in 1982.

• J.D. Bjorken, S. Drell (1964). Relativistic Quantum Mechanics.
  ISBN 0-07-005493-2
  .
• J.D. Bjorken, S. Drell (1965). Relativistic Quantum Fields.
  ISBN 0-07-005494-0
  .

• J. D. Bjorken (1968). "Current Algebra at Small Distances", in Proceedings of the International School of Physics Enrico Fermi Course XLI, J. Steinberger, ed., Academic Press, New York, pp. 55–81. Online, SLAC-PUB-338
• J.D. Bjorken (1969). "Asymptotic Sum Rules at Infinite Momentum" (PDF).
  OSTI 1444603
  .