Preface to Volume 2 of the Fourth
Edition
The main focus of the second volume of this fourth edition, as in the third, is
on the two non-Abelian quantum gauge field theories of the Standard Model
– that is, QCD and the electroweak theory of Glashow, Salam and Weinberg.
We preserve the same division into four parts: non-Abelian symmetries, both
global and local; QCD and the renormalization group; spontaneously broken
symmetry; and weak interaction phenomenology and the electroweak theory.
However, the book has always combined theoretical development with discussion of relevant experimental results. And it is on the experimental side
that most progress has been made in the ten years since the third edition
appeared – first of all, in the study of CP violation in B-meson physics, and
in neutrino oscillations. The inclusion of these results, and the increasing importance of the topics, have required some reorganization, and a new chapter
(21) devoted wholly to them. We concentrate mainly on CP-violation in Bmeson decays, particularly on the determination of the angles of the unitarity
triangle from B-meson oscillations. CP-violation in K-meson systems is also
discussed. In the neutrino sector, we describe some of the principal experiments which have led to our current knowledge of the mass-squared differences
and the mixing angles. In discussing weak interaction phenomenology, we keep
in view the possibility that neutrinos may turn out to be Majorana particles,
an outcome for which we have prepared the reader in (new) chapters 4 and 7
of volume 1.
More recently, on July 4, 2012, the ATLAS and CMS collaborations at
the CERN LHC announced the discovery of a boson of mass between 125 and
126 GeV, with production and decay characteristics which are consistent (at
the 1σ level) with those of the Standard Model Higgs boson. We can now
conclude our treatment of the electroweak theory, and this volume, with a
discussion of this historic discovery, which opens a new era in particle physics
– one in which the electroweak symmetry-breaking (Higgs) sector of the SM
will be rigorously tested.
Our treatment of a number of topics has been updated and, we hope, im−
proved. In QCD, the definition of 2-jet cross sections in e
+ e annihilation
is explained, and used in a short discussion of jet algorithms (sections 14.5
and 14.6). Progress in lattice QCD is recognized with the inclusion of some
of the recent impressive results using dynamical fermions (section 16.5). In
the chapter on chiral symmetry breaking, a new section (18.3) introduces the
xiii
Edition
The main focus of the second volume of this fourth edition, as in the third, is
on the two non-Abelian quantum gauge field theories of the Standard Model
– that is, QCD and the electroweak theory of Glashow, Salam and Weinberg.
We preserve the same division into four parts: non-Abelian symmetries, both
global and local; QCD and the renormalization group; spontaneously broken
symmetry; and weak interaction phenomenology and the electroweak theory.
However, the book has always combined theoretical development with discussion of relevant experimental results. And it is on the experimental side
that most progress has been made in the ten years since the third edition
appeared – first of all, in the study of CP violation in B-meson physics, and
in neutrino oscillations. The inclusion of these results, and the increasing importance of the topics, have required some reorganization, and a new chapter
(21) devoted wholly to them. We concentrate mainly on CP-violation in Bmeson decays, particularly on the determination of the angles of the unitarity
triangle from B-meson oscillations. CP-violation in K-meson systems is also
discussed. In the neutrino sector, we describe some of the principal experiments which have led to our current knowledge of the mass-squared differences
and the mixing angles. In discussing weak interaction phenomenology, we keep
in view the possibility that neutrinos may turn out to be Majorana particles,
an outcome for which we have prepared the reader in (new) chapters 4 and 7
of volume 1.
More recently, on July 4, 2012, the ATLAS and CMS collaborations at
the CERN LHC announced the discovery of a boson of mass between 125 and
126 GeV, with production and decay characteristics which are consistent (at
the 1σ level) with those of the Standard Model Higgs boson. We can now
conclude our treatment of the electroweak theory, and this volume, with a
discussion of this historic discovery, which opens a new era in particle physics
– one in which the electroweak symmetry-breaking (Higgs) sector of the SM
will be rigorously tested.
Our treatment of a number of topics has been updated and, we hope, im−
proved. In QCD, the definition of 2-jet cross sections in e
+ e annihilation
is explained, and used in a short discussion of jet algorithms (sections 14.5
and 14.6). Progress in lattice QCD is recognized with the inclusion of some
of the recent impressive results using dynamical fermions (section 16.5). In
the chapter on chiral symmetry breaking, a new section (18.3) introduces the
xiii