F?lix J. Elements of high energy physics
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Elements of High
Energy Physics
Julián Félix
e-libro.net
Elements of High
Energy Physics
© 2004, por Julián Félix Valdez
© Primera edición virtual y en papel, e-libro.net,
Buenos Aires, julio de 2004
ISBN 1-4135-3536-4, de la edición virtual
ISBN 1-4135-3537-2, de la edición impresa
Education is the most precious gem that someone can give to
someone else.
Material possessions are ephemeral; education skills, perennial.
Human beings perceive and interpret the external world
through their glass window education. Give them a sane
education, and the world will look level-headed.
Give good education and noble motives to people and you will
make the world moves rightly.
To those that have been original enough to think by
themselves, to trace, and to open new roads to educate people.
And to those that have been courageous enough to try them.
Juli´an F´elix
Instituto de F´ısica, Universidad de Guanajuato
Le´on Guanajuato, M´exico.
With the help of la Fundaci´on DELTA, A.C. and of the grant
CoNaCyt-2002-C01-39941/A-1.
v
Preface
There are many wrong practices, procedures, and policies in the south
countries: The worse is in people education. Sometimes, this has no defined
purposes and orientations. The idea of the state is to provide education to
people, even if that education has nothing to do with the State; even if that
education is not integrated in one project of State -or nation-, that hits its
economy, security, integrity, etc.
The policies to introduce, to teach, and to learn, science in that south
countries are even worse: Science is taught like if it were a religion, without
relation with engineering and the external world; only at the textbook level
and using repetitive and memoriter procedures. Completely separated from
the physical and economical country reality.
Physics is not excluded from that situation. It is taught completely
separated from the physical reality of the external world and from the
economical reality of the state. The Mexican schools of sciences -physics-
reach the 5% of efficiency. And teach physics with a parody of physics
laboratories -when there have been some efforts to construct them, because
in some universities students never enter a physics laboratory- and using
textbooks translated into Spanish, generally from English. It is worthless to
say that physics students never accomplish a serious experiment in physics;
and that they graduate from physics implicitly believing that physics is not
from this world.
Because that situation, students -also teachers and professors- are in-
volved in a paradoxical situation and perverse circle: They learn wrongly
physics because their mentors learnt badly physics; teachers teach in a
wrong way for they were tough also in a wrong manner. And the country is
ElementsofHighEnergyPhysics
technological underdeveloped because the poor way physics is tough, and
because the p oor way science is tough the country is technological under-
developed.
This book Elements of High Energy Physics is an intent to change that
paradoxical situations in teaching and learning physics; to break down that
vicious circle of bad teaching physics and technological underdevelopment,
that engulfs the majority of the countries in these times.
The worse those country people teach and learn physics, the more un-
derdeveloped nations they form. Country technological development and
country good education are very close related. The more skillful those na-
tion people are, the richest they are. Mexico country exemplifies very well
this situation.
This book will have a Spanish version, for use in Mexico and other
Spanish speaker countries. To alleviate the situation, the vicious circle, in
learning and teaching physics and technological underdevelopment.
vii
Contents
Prefacevi
1. Introduction 1
2. Physics 5
2.1 Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.1 Physics and the External World . . . . . . . . . . . . 9
2.1.2 Precepts of Physics . . . . . . . . . . . . . . . . . . . 12
2.1.2.1 Classical Precepts . . . . . . . . . . . . . . . 12
2.1.2.2 Quantum Precepts . . . . . . . . . . . . . . 15
2.1.3 Theorization and Experimentation . . . . . . . . . . 20
2.1.3.1 Theorization . . . . . . . . . . . . . . . . . . 20
2.1.3.2 Experimentation . . . . . . . . . . . . . . . 26
2.2 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3. Experimental High Energy Physics 43
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.2 Atom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.3 Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
3.4 Families of Particles . . . . . . . . . . . . . . . . . . . . . . 53
3.5 Classification of Particles . . . . . . . . . . . . . . . . . . . 56
3.6 Quark Model . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.7 A High Energy Physics Experiment . . . . . . . . . . . . . . 62
3.7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 63
3.7.2 Scintillator Detectors . . . . . . . . . . . . . . . . . . 65
3.7.3 Multiwire Proportional Chambers . . . . . . . . . . . 66
ElementsofHighEnergyPhysics
3.7.4 Cerenkov Counters . . . . . . . . . . . . . . . . . . . 67
3.7.5 Monte Carlo Method . . . . . . . . . . . . . . . . . . 68
3.7.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . 69
4. High Energy Physics Practical Utility 85
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
4.2 To know the Nature of Nature . . . . . . . . . . . . . . . . 86
4.3 Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
4.4 New Materials . . . . . . . . . . . . . . . . . . . . . . . . . 99
4.5 Computation . . . . . . . . . . . . . . . . . . . . . . . . . . 100
4.6 New Technologies . . . . . . . . . . . . . . . . . . . . . . . . 102
4.7 Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
4.7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 105
4.7.2 X Rays . . . . . . . . . . . . . . . . . . . . . . . . . . 106
4.7.3 Other Techniques . . . . . . . . . . . . . . . . . . . . 109
4.7.4 Study of the Brain . . . . . . . . . . . . . . . . . . . 111
4.7.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . 112
4.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Bibliography 117
Index 119
ix
Chapter 1
Introduction
Teachers have not pronounced the last word on teaching; nor physics teach-
ers have pronounced the last word on teaching physics. And researchers
have not pronounced the last word on research and physics researchers nor
on physics research.
In formal courses of physics, teachers or instructors do not leave explic-
itly what physics is and what is its utility, nor what is its relation with
external world, or technology, or daily life objects and machines. Or how
physics leads to a deep understanding of the external world behavior. At
least in Latin America, the main problem is from the teacher -in all levels
of instruction- who presents and conduces the course. The problem is akin
in the rest of the world, especially in the underdeveloped countries. The
teacher is the ultimate responsible person on the way he conduces the course
and on the way students are taught and of what and how students learn.
Most of the time, teachers deliver to students as a science -physics- a col-
lection of dead facts, data, and technical terms, in a way that is more akin
to religion than to science; in both contents and way of learning. Without
immediate connection with external world. Students learn physics believing
facts.
Science is not that. Physics is not that. Science is alive human activity.
Physics is alive science, growing and changing continuously, and everyday.
Very close to the way human beings perceive the external world.
Physics is alive, always growing, science, not a static religion. Physics
is the description and interpretation of the external world. The description
and the interpretation of external world let physicist understand the way