Pictures Paths Particles Processes

Chapter 0
Prolegomena
0.1 Preface
In what follows, whatever is correct I owe to many other people ; that which
is wrong I managed on my own. I am perpetually in need of, and grateful to,
those pointing out typing or thinking errors in these notes 1 .
Writing about relativistic quantum field theory and its consequences for
particle phenomenology is not an especially easy task. On the one hand the
literature abounds with textbooks – often admirable ones – with titles containing
the words ‘Introduction’, ‘Quantum’, and ‘Field Theory’, and it might be
wondered what yet another such a one could contribute to that which has already
been expanded upon into excruciating detail. Indeed, the serious student
can graze and ruminate to heart’s content in the meadows of existing literature.
On the other hand, almost everyone who has taught courses containing
the words ‘Introduction’, ‘Quantum’, or ‘Field Theory’ will have felt, upon occasion,
that some or several subjects have not, in the available corpus, been
presented with exactly the right emphasis on points especially dear, or along
the precisely favourite line of thought on this or that crucial argument. I therefore
add my mite : a small one, but mine own ; I shall present the content of
relativistic quantum field theory, and the way in which it purports to describe
the world of elementary particles and their interactions, in the manner most
pleasing to myself. The æsthetics of such a story are sometimes undervalued
but ultimately as important as its other aspects.
The content matter of these notes is nothing but what the existing literature
discusses, with an emphasis on the acquisition of calculating skills which
should enable the diligent to actually compute scattering cross sections and
1 I cordially invite all and sundry to do so. The P 4 Hall of Fame collects the names of
friends who have helped me in learning about, formulating, contemplating, or execrating one
or several issues.
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