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James Bjorken

 
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James Bjorken
 
 
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James Daniel "Bj" Bjorken (born 1934) is one of the world's foremost theoretical physicists. He was a Putnam Fellow in 1954 and obtained his Ph.D. from Stanford University
Stanford University

Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private university research university located in Stanford, California, California, United States....
 in 1959. He is Emeritus Professor at the Stanford Linear Accelerator Center
Stanford Linear Accelerator Center

The SLAC National Accelerator Laboratory, originally named Stanford Linear Accelerator Center, is a United States Department of Energy United States Department of Energy National Laboratories operated by Stanford University under the programmatic direction of the U.S....
, and was a member of the Theory Department of the Fermi National Accelerator Laboratory (1979-1989).

Bjorken discovered what is known as Light-Cone Scaling, (or "Bjorken-Scaling") a phenomenon in the deep inelastic scattering of light on strongly interacting particles, like protons and neutrons (known as hadron
Hadron

In particle physics, a hadron is a bound state of quarks. Hadrons are held together by the strong interaction, similarly to how molecules are held together by the electromagnetic force....
s).






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James Daniel "Bj" Bjorken (born 1934) is one of the world's foremost theoretical physicists. He was a Putnam Fellow in 1954 and obtained his Ph.D. from Stanford University
Stanford University

Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private university research university located in Stanford, California, California, United States....
 in 1959. He is Emeritus Professor at the Stanford Linear Accelerator Center
Stanford Linear Accelerator Center

The SLAC National Accelerator Laboratory, originally named Stanford Linear Accelerator Center, is a United States Department of Energy United States Department of Energy National Laboratories operated by Stanford University under the programmatic direction of the U.S....
, and was a member of the Theory Department of the Fermi National Accelerator Laboratory (1979-1989).

Bjorken discovered what is known as Light-Cone Scaling, (or "Bjorken-Scaling") a phenomenon in the deep inelastic scattering of light on strongly interacting particles, like protons and neutrons (known as hadron
Hadron

In particle physics, a hadron is a bound state of quarks. Hadrons are held together by the strong interaction, similarly to how molecules are held together by the electromagnetic force....
s). This was critical to the recognition of quark
Quark

Quarks are a type of elementary particle and major constituents of matter. They are the only particles in the Standard Model to experience all four fundamental interaction, which are also known as fundamental interactions....
s as actual fundamental particles (rather than just convenient theoretical constructs), and led to the theory of strong interactions known as quantum chromodynamics
Quantum chromodynamics

Quantum chromodynamics is a theory of the strong interaction , a fundamental force describing the interactions of the quarks and gluons making up hadrons ....
.

In Bjorken's picture, the quarks become point-like, observable objects at very short distances (high energies). Richard P. Feynman subsequently reformulated this concept into the parton
Parton (particle physics)

In particle physics, the parton model was proposed by Richard Feynman in 1969 as a way to analyze high-energy hadron collisions. It was later recognized that partons describe the same objects now more commonly referred to as quarks and gluons....
 model, used by many physicists to understand the quark composition of hadrons when probed at high energies.

The predictions of Bjorken Scaling were confirmed in the electroproduction experiments at SLAC in the early 1970's in which quarks were seen for the first time. The general idea, with small logarithmic modifications, is explained in Quantum Chromodynamics
Quantum chromodynamics

Quantum chromodynamics is a theory of the strong interaction , a fundamental force describing the interactions of the quarks and gluons making up hadrons ....
 by "asymptotic freedom." Many believe Bjorken should have been awarded a Nobel Prize
Nobel Prize in Physics

The Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in chemistry, Nobel Prize in literature, Nobel Peace Prize, and Nobel Prize in physiology or medicine....
 for this discovery, which was central to the revolutions in particle physics in the 1970's.

Bjorken co-authored, with Sidney Drell
Sidney Drell

Sidney Drell is an United States theoretical physics and arms control expert.He is a professor emeritus at the Stanford Linear Accelerator Center and a fellow at the Hoover Institution....
, a classic companion volume textbook on Relativistic Quantum Mechanics and Quantum Fields that is still used by many practicing particle physicists.

Publications


Books

  • Bjorken, James and Drell, Sidney. "Relativistic Quantum Mechanics", McGraw-Hill (1964). ISBN 0-07-005493-2
  • Bjorken, James and Drell, Sidney. "Relativistic Quantum Fields", McGraw-Hill (1965). ISBN 0-07-005494-0

Papers

  • J. D. Bjorken, "Asymptotic Sum Rules at Infinite Momentum", Phys. Rev. 179, 1547-1553 (1969).