11 Forces in the Standard Model and Symmetries
83
It gives every quark and lepton their mass and every force its range and is thus
a very fundamental part of the story of the standard model.
This mechanism was suggested in three papers, first by R. Brout and F.
Englert of the University of Brussels, second by Peter Higgs of Edinburgh
University, and in a third paper by Gerald Guralnik, Carl Hagen and Tom
Kibble of the Imperial College, London. They showed how a force given by
a symmetry operating at every space-time point, independently (called gauge
symmetry above), can acquire its short range. Since such a symmetry requires
that all forces be long range in the symmetric limit, the symmetry must be
broken to give the force a range. In this mechanism, the symmetry is broken
by the environment of the theory (like the stick falling due to gravity). These
authors put this simple idea into a mathematical framework, which can be
used to build theories of the universe. That is a pretty big accomplishment.
These ground breaking papers were recognized in 2013. The Nobel Prize
awarded to F. Englert and Peter Higgs, after the Higgs boson was discovered
in 2012 at the CERN Large Hadron Collider. Robert Brout had died by that
time and Guralnik et al were left out, presumably because the Nobel Prize
cannot be given to more than three people at a time and their paper was
chronologically the last of the three papers. For a detailed discussion of the
contribution of Hagen, Guralnik, and Kibble, see [31]. This discovery of the
Higgs boson was a major triumph of theoretical as well as experimental physics
and a crowning success for the enormous efforts that went into building
the Large Hadron Collider, the mammoth machine in Geneva, Switzerland.
More than 10,000 physicists from all over the world worked at the LHC
on this experiment, constantly monitoring the machine for its performance
and analyzing its results. The machine pipes are maintained at a very low
temperature and at very high magnetic field, each a major task. In addition
to the discovery of the Higgs boson, which was the first success of LHC, it is
giving many other extremely valuable pieces of information about a lot of other
physics ideas beyond the standard model. The discovery of the Higgs boson
essentially confirmed the standard model in all its aspects, and provided for
the first time a complete theory that partially unified three of the four known
forces of nature.
For a long time, it was not clear whether one can do useful calculations
using a spontaneously broken gauge theory and make predictions that can test
the theory. In a seminal paper, Gerard ’t Hooft showed in 1972 that indeed
this can be done and ’t Hooft was awarded the Nobel Prize for this work in
1999, along with his thesis advisor M. T. Veltman.
83
It gives every quark and lepton their mass and every force its range and is thus
a very fundamental part of the story of the standard model.
This mechanism was suggested in three papers, first by R. Brout and F.
Englert of the University of Brussels, second by Peter Higgs of Edinburgh
University, and in a third paper by Gerald Guralnik, Carl Hagen and Tom
Kibble of the Imperial College, London. They showed how a force given by
a symmetry operating at every space-time point, independently (called gauge
symmetry above), can acquire its short range. Since such a symmetry requires
that all forces be long range in the symmetric limit, the symmetry must be
broken to give the force a range. In this mechanism, the symmetry is broken
by the environment of the theory (like the stick falling due to gravity). These
authors put this simple idea into a mathematical framework, which can be
used to build theories of the universe. That is a pretty big accomplishment.
These ground breaking papers were recognized in 2013. The Nobel Prize
awarded to F. Englert and Peter Higgs, after the Higgs boson was discovered
in 2012 at the CERN Large Hadron Collider. Robert Brout had died by that
time and Guralnik et al were left out, presumably because the Nobel Prize
cannot be given to more than three people at a time and their paper was
chronologically the last of the three papers. For a detailed discussion of the
contribution of Hagen, Guralnik, and Kibble, see [31]. This discovery of the
Higgs boson was a major triumph of theoretical as well as experimental physics
and a crowning success for the enormous efforts that went into building
the Large Hadron Collider, the mammoth machine in Geneva, Switzerland.
More than 10,000 physicists from all over the world worked at the LHC
on this experiment, constantly monitoring the machine for its performance
and analyzing its results. The machine pipes are maintained at a very low
temperature and at very high magnetic field, each a major task. In addition
to the discovery of the Higgs boson, which was the first success of LHC, it is
giving many other extremely valuable pieces of information about a lot of other
physics ideas beyond the standard model. The discovery of the Higgs boson
essentially confirmed the standard model in all its aspects, and provided for
the first time a complete theory that partially unified three of the four known
forces of nature.
For a long time, it was not clear whether one can do useful calculations
using a spontaneously broken gauge theory and make predictions that can test
the theory. In a seminal paper, Gerard ’t Hooft showed in 1972 that indeed
this can be done and ’t Hooft was awarded the Nobel Prize for this work in
1999, along with his thesis advisor M. T. Veltman.