10
Standard Model of the Particles and Forces
Experimental evidence to date seems to suggest that the constituents which
make up all matter, and particles responsible for known forces in the universe,
are now fully understood within the framework of the so-called standard
model. This model was invented by Glashow, Weinberg, and Salam in the
1960s. This does not include the recent discoveries involving neutrinos. In
this chapter, we give a quick run-down of the basic ingredients of the standard
model. We describe the particles in the model in this chapter, and what
determines the forces in the following one. In the chapter following the next,
we also discuss the mysteries that provide the clue to go beyond the standard
model.
10.1 How Charming was the Charm Quark?
As already described above, quarks are the fundamental constituents of protons, neutrons, pions, and in fact all known particles that participate in the
strong interactions (called hadrons). They made their debut in chapter two.
We called them up (u) and down (d) quarks. To explain the existence of Kmesons and hyperons, one needed to introduce another kind of quark, called
the strange quark (denoted by the letter “s”).
The next quark, the charm quark, had an interesting history. It shows
how important hunches based on symmetry can be insightful and decisive.
Prior to the discovery of the muon neutrino, Gamba, Marshak, and Okubo
noticed a symmetry between the electron, muon, and the electron neutrino
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer
Nature Switzerland AG 2021
R. N. Mohapatra, The Neutrino Story: One Tiny Particle’s Grand Role in the Cosmos,
https://doi.org/10.1007/978-3-030-51846-2_10
71
Standard Model of the Particles and Forces
Experimental evidence to date seems to suggest that the constituents which
make up all matter, and particles responsible for known forces in the universe,
are now fully understood within the framework of the so-called standard
model. This model was invented by Glashow, Weinberg, and Salam in the
1960s. This does not include the recent discoveries involving neutrinos. In
this chapter, we give a quick run-down of the basic ingredients of the standard
model. We describe the particles in the model in this chapter, and what
determines the forces in the following one. In the chapter following the next,
we also discuss the mysteries that provide the clue to go beyond the standard
model.
10.1 How Charming was the Charm Quark?
As already described above, quarks are the fundamental constituents of protons, neutrons, pions, and in fact all known particles that participate in the
strong interactions (called hadrons). They made their debut in chapter two.
We called them up (u) and down (d) quarks. To explain the existence of Kmesons and hyperons, one needed to introduce another kind of quark, called
the strange quark (denoted by the letter “s”).
The next quark, the charm quark, had an interesting history. It shows
how important hunches based on symmetry can be insightful and decisive.
Prior to the discovery of the muon neutrino, Gamba, Marshak, and Okubo
noticed a symmetry between the electron, muon, and the electron neutrino
© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer
Nature Switzerland AG 2021
R. N. Mohapatra, The Neutrino Story: One Tiny Particle’s Grand Role in the Cosmos,
https://doi.org/10.1007/978-3-030-51846-2_10
71