Chapter 6
The Discovery of the Higgs Boson
at the LHC
Peter Jenni and Tejinder S. Virdee
6.1 Introduction and the Standard Model
The standard model of particle physics (SM) is a theory that is based upon principles
of great beauty and simplicity. The theory comprises the building blocks of visible
matter, the fundamental fermions: quarks and leptons, and the fundamental bosons
that mediate three of the four fundamental interactions; photons for electromagnetism, the W and Z bosons for the weak interaction and gluons for the strong
interaction (Fig. 6.1).
The SM provides a very successful description of the visible universe and has
been verified in many experiments to a very high precision. It has an enormous range
of applicability and validity. So far no significant deviations have been observed
experimentally.
The possibility of installing a proton-proton accelerator in the LEP tunnel, after
the e + e − programme, was being discussed in the 1980’s. At the time there were
many profound open questions in particle physics, and several are still present. In
simple terms these are: what is the origin of mass i.e. how do fundamental particles
acquire mass, and why do they have the masses that they have? Why is there more
matter than anti-matter? What is dark matter? What is the path towards unification of
all forces? Do we live in a world with more space-time dimensions than the familiar
four? The LHC [1, 2] was conceived to address or shed light on these questions.
P. Jenni
CERN, Geneva, Switzerland
Albert-Ludwigs University Freiburg, Freiburg im Breisgau, Germany
T. S. Virdee ()
Imperial College London, London, UK
e-mail: Tejinder.Virdee@cern.ch
© The Author(s) 2020
H. Schopper (ed.), Particle Physics Reference Library,
https://doi.org/10.1007/978-3-030-38207-0_6
263
The Discovery of the Higgs Boson
at the LHC
Peter Jenni and Tejinder S. Virdee
6.1 Introduction and the Standard Model
The standard model of particle physics (SM) is a theory that is based upon principles
of great beauty and simplicity. The theory comprises the building blocks of visible
matter, the fundamental fermions: quarks and leptons, and the fundamental bosons
that mediate three of the four fundamental interactions; photons for electromagnetism, the W and Z bosons for the weak interaction and gluons for the strong
interaction (Fig. 6.1).
The SM provides a very successful description of the visible universe and has
been verified in many experiments to a very high precision. It has an enormous range
of applicability and validity. So far no significant deviations have been observed
experimentally.
The possibility of installing a proton-proton accelerator in the LEP tunnel, after
the e + e − programme, was being discussed in the 1980’s. At the time there were
many profound open questions in particle physics, and several are still present. In
simple terms these are: what is the origin of mass i.e. how do fundamental particles
acquire mass, and why do they have the masses that they have? Why is there more
matter than anti-matter? What is dark matter? What is the path towards unification of
all forces? Do we live in a world with more space-time dimensions than the familiar
four? The LHC [1, 2] was conceived to address or shed light on these questions.
P. Jenni
CERN, Geneva, Switzerland
Albert-Ludwigs University Freiburg, Freiburg im Breisgau, Germany
T. S. Virdee ()
Imperial College London, London, UK
e-mail: Tejinder.Virdee@cern.ch
© The Author(s) 2020
H. Schopper (ed.), Particle Physics Reference Library,
https://doi.org/10.1007/978-3-030-38207-0_6
263