F?lix J. Elements of high energy physics

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32 Elements of High Energy Physics

forward. Opened new perspectives in physics. And permitted the possibil-

ity of creating new branches of physics. Like special and general relativity.

Theory of information. Experimental philosophy. Crystallography. And

many others.

Physics is an experimental science. This is an unavoidable truth. For

physicists understand the world it is indispensable that they have a percep-

tual image created and supported by experimental evidence. A collection

of experimental data does not give us an image about the universe. In

the same way, a collection of axioms, without experimental support, nei-

ther give us an image about the external world. Both constructions are

possible. And indeed exist: Weather collection data and modern alge-

bra are instances, respectively. The image of the world is constructed on

the experimental and axiomatic truth. The axioms must be supported by

the most complete experimental evidence. And the logical implications

of those axioms must have experimental corroboration, experimental facts

that necessarily must b e happening, and were unknown up to when they

were unveiled by logical thought.

Physics history registers many examples: Electromagnetic waves pre-

dicted by Maxwell; particle wave nature, by De Broglie; time dilation, by

Einstein. And many others.

Earth surface

cosmic ray proton collisions

at 400 km above sea level

electronics

muon detectors

muons and other

leptons and hadrons

Fig. 2.1 Muon production very high in the earth atmosphere and arrival at earth surface, where they are detected.

(1)

(2)

(3)

(4)

(5)

(6)

(1): proton accelerator

(2): pion production

(3): pion decay channel

(4): muon cooling channel

(5): muon accelerator

(6): muon collider

Fig. 2.2 Scheme of muon antimuon collider.

Fig. 2.3 Very old laboratory blackbody.

Fig. 2.4 Blackbody radiation distribution of the entire universe at 2.735 K. Radiation density per unit wavelength.

Fig. 2.5 Polar Star blackbody radiation distribution at 8300 K. Radiation density per unit wavelength.

Fig. 2.6 Sun blackbody radiation distribution at 5700 K. Radiation density per unit wavelength.

Fig. 2.7 Two blackbody radiation distributions at two diﬀerent temperatures, open circles and ﬁlled triangles. Radiation density per

unit wavelength.

Fig. 2.8 Two blackbody radiation distributions at two diﬀerent temperatures, open circles and ﬁlled triangles. Radiation density per

unit wavelength. And Planck theory predictions, solid line.

Fig. 2.9 Comparison of ideal blackbody radiation distribution with quartz radiation distribution. In the average they agree.