The past decade has been one of continual ferment and extraordinary
achievement in high-energy physics. The constituent (quark model)
picture of the strongly interacting particles has steadily gained
experimental support from the pointlike character of inelastic
electron-proton scattering, the jet structures observed in electron-positron
annihilation, the atom-like spectra of the ψ/J and Υ
families of resonances, and more. Simultaneously, confidence has
grown in the view that interactions among the fundamental constituents are
described by gauge field theories. Prominent examples are the
Weinberg–Salam model of weak and electromagnetic interactions and quantum
chromodynamics, the gauge theory of strong interactions among quarks and
This new perspective has been shaped by both theoretical and experimental
advances: the proof that the Weinberg-Salam theory is renormalizable, the
discovery of weak neutral currents and the observation of
charm; the recognition that gauge. theories may be asymptotically free;
the measurement of Bjorken-scaling violations in inelastic lepton-nucleon
scattering, and the evidence for gluon jets. With this new perspective
have come new experimental initiatives, including imminent searches for
the intermediate bosons of the weak interactions, for proton instability and
for neutrino oscillations.
In my view, high-energy physics is defined by what high-energy physicists
are doing and a graduate course should introduce students to contemporary
concerns. The selection of apposite topics is no easy task for the author
of a textbook on such a rapidly moving field. In Elementary Particle
Physics, David C. Cheng and Gerald K. O'Neill have chosen not to write a
thoroughly modern introduction to particle physics, but rather to emphasize
time-honored material. Unfortunately "time honored" all too often means
antique. The book is divided into a brief introduction and major
sections on the electromagnetic, weak, and strong interactions. The
strong-interaction portion, which makes up 40% of the text, contains
only three post-1969 references: passing mention of the papers announcing
asymptotic freedom and a
citation of the 1978 Review of Particle Properties. The extensive studies
of high-energy collisions carried out at the CERN Intersecting Storage
Rings, at Fermilab, and at the CERN Super Proton Synchrotron are thus
ignored. This is regrettable, even within the authors' selection criteria,
because many experiments and analyses of the recent era address
traditional concerns more incisively than did earlier work. The rest of
the book is scarcely more modern: it contains a half-dozen post-1975
references en passant.
Such complaints might be overlooked if Elementary Particle Physics were
otherwise well-written. However, Cheng, a former high-energy experimenter
now with Intel Magnetics and O'Neill, professor of physics at
Princeton and a pioneer of colliding-beams research, have produced a
disappointing book. It contains many statements that are misleading and
many that are wrong.
For example, in a lengthy treatment of SU(3) and the quark model, there is
continual confusion between the terminology "group" and "representation."
The difference between SU(3) and the quark model is garbled, the
photon is incorrectly described as isoscalar, and it is stated, also
incorrectly, that charm as well as color is needed to
reconcile the quark model with the Pauli exclusion principle.
A section on Regge theory (the utility of which has been confirmed by the
high-energy experiments the book neglects) highlights something called the
"interference model," which has been discredited since the discovery of
duality in the late 1960s. The authors say that the total cross section
should decrease as l/log (center-of-mass energy). What should be meant is
the elastic cross section. In any event, the big news of early 1973—not
mentioned here—is that both grow with increasing energy.
The section on weak interactions contains a brief resume of the
Weinberg–Salam model in which a partial-wave unitarity argument is
given for the existence of the neutral intermediate boson Z0.
The mass of the Z0 is incorrectly stated to be twice the mass of the charged
intermediate boson W±. The Higgs boson, whose existence is
required by the same unitarity argument, is not mentioned, The theory is
ascribed to Steven Weinberg in 1964 (1967 is correct), but the reference
does not exist: it turns out to be a corrupted reference to the work of
Abdus Salam and John Ward.
As these examples suggest, Elementary Particle Physics is so
consistently unreliable that no student should be forced to struggle with
it. I may suggest some alternatives. For a one-year course, the books by
Steven Gasiorowicz and by Martin Perl, though somewhat dated, are more
scholarly and authoritative, and an excellent short introduction is
provided by Donald Perkins's slender volume.
Chris Quigg is a theoretical physicist at the Fermi National Accelerator
Laboratory in Batavia, Illinois.