Particle Physics: A Very Short Introduction

In this compelling introduction to the fundamental particles that make up the universe, Frank Close takes us on a journey into the atom to examine known particles such as quarks, electrons, and the ghostly neutrino. Along the way he provides fascinating insights into how discoveries in particle physics have actually been made, and discusses how our picture of the world has been radically revised in the light of these developments. He concludes by looking ahead to new ideas about the mystery of antimatter, the number of dimensions that there might be in the universe, and to what the next 50 years of research might reveal.

[...]... contact with any, as it is estimated that there is less than an ounce of astatine in the Earth’s crust, and as for francium it has even been claimed that at any instant there are at most 20 atoms of it around Particle Physics An atom is the smallest piece of an element that can exist and still be recognized as that element Nearly all of these elements, such as the oxygen that you breathe and the carbon... billion years ago in a hot Big Bang, it was then that the seeds of matter were formed From quarks to quasars Stars are huge, and visible to the naked eye over vast distances This is in stark contrast to their basic components, the particles that eventually make up atoms It would take about a billion atoms placed on top of one another to reach your head; it would take a similar number of people head to... forces of Nature Gravity is attractive and controls the large-scale motions of galaxies, planets, and falling apples Electric and magnetic forces hold electrons in the outer reaches of atoms They can be attractive or repulsive, and tend to counterbalance in bulk matter, leaving gravity dominant at large distances The strong force glues quarks to one another, forming neutrons, protons, and other particles... in turn are made of yet smaller particles: the ‘quarks’ Quarks and electrons are the seeds of matter as we find it on Earth Whereas the atom is typically 10−10 m across, its central nucleus measures only about 10−14 to 10−15 m So beware the oft-quoted analogy that atoms are like miniature solar systems with the ‘planetary electrons’ encircling the ‘nuclear sun’ The real solar system has a factor 1/100... (2-mile-) long linear accelerator at the Stanford Linear Accelerator Center 56 21 Subatomic particles viewed in the bubble chamber at CERN 22 Attraction and repulsion rules for colour charges 86 66 23 Beta decay via W © Goronwy Tudor Jones, University of Birmingham/ Science Photo Library 16 Tracks of charged particles 68 © CERN/Science Photo Library 17 The W particle 70 Track of a fast beta-ray electron 75... it was the details that were wrong Their ‘earth, air, fire, and water’ are made of what today we know as the chemical elements Pure water is made from two: hydrogen and oxygen Air is largely made from nitrogen and oxygen with a dash of carbon and argon The Earth’s crust contains most of the 90 naturally occurring elements, primarily oxygen, silicon, and iron, mixed with carbon, phosphorus and many others... we shall see later, this cannot happen spontaneously; an electron and its antimatter counterpart – the positron – must be created as a pair So 1 MeV energy is needed for ‘electron positron creation’ to occur Analogously, 2 GeV energy is needed to create a proton and its antiproton Such energies are easy to generate in nuclear laboratories and particle accelerators today; they were the norm in the very. .. out what something is made of you might (a) look at it; (b) heat it and see what happens; or (c) smash it by brute force There is a common misconception that it is the latter that high-energy, or particle , physicists do This is a term left from the days when particle accelerators were known as ‘atom smashers’ And indeed, historically that was what took place, but today the aims and methods are more... plus innumerable animals, and there are plenty more oxygen atoms around doing other things As you exhale these atoms are emitted, entrapped with carbon to make molecules of carbon dioxide, the fuel for trees and plants The numbers are vast and the names of oxygen and carbon are in everyone’s lexicon Contrast this with astatine or francium Even if you have heard of them, you are 1 unlikely to have come... radio waves, or the atoms of our DNA Today we can use instruments to extend our senses: telescopes that study the depths of space and microscopes to reveal bacteria and molecules We have special ‘microscopes’ to reveal distances smaller than atoms: this is the role of high-energy particle accelerators By such tools we can reveal nature over a vast range of distance scales How this is done for particles . now: ANCIENT PHILOSOPHY Julia Annas THE ANGLO-SAXON AGE John Blair ANIMAL RIGHTS David DeGrazia ARCHAEOLOGY Paul Bahn ARCHITECTURE Andrew Ballantyne ARISTOTLE.