Techniques and Concepts of High-Energy Physics V

507 Pages·1990·19.882 MB·English

by  Guido Martinelli (auth.), Thomas Ferbel (eds.)

Techniques and Concepts
of High-Energy
Physics V
NATO ASI Se ries
Advanced Science Institutes Series
Aseries presenting the results ot activities sponsored by the NA TO Science Committee,
which aims at the dissemination pt advanced scientific and technological knowledge,
with a view to strengthening links between scientific communities.
The series is published by an international board of publishers in conjunction with the
NATO Scientific Affairs Division
A Life Sciences Plenum Publishing Corporation
B Physics New York and London
C Mathematical Kluwer Academic Publishers
and Physical Sciences Dordrecht, Boston, and London
D Behavioral and Social Sciences
E Applied Sciences
F Computer and Systems Sciences Springer-Verlag
G Ecological Seien ces Berlin, Heidelberg, New York, London,
H Cell Biology Paris, and TOkyo
Reeent Volumes in this Series
Va/ume 19B-Mechanisms of Reactions of Organometallic
Compounds with Surfaces
edited by D. J. Cole-Hamilton and J. O. Williams
Va/ume 199-Science and Technology of Fast Ion Conductors
edited by H. L. Tuller and M. Balkanski
Va/ume 200-Growth and Optical Properties of Wide-Gap li-VI
Low Dimensional Semiconductors
edited by T. C. McGill, C. M. Sotomayor Torres,
and W. Gebhardt
Va/ume 201-Physics of Highly-Ionized Atoms
edited by Richard Marrus
Va/ume202-Point and Extended Defects in Semiconductors
edited by G. Benedek, A. Cavallini, and W. Schröter
Va/ume203-Evaluation of Advanced Semiconductor Materials
by Electron Microscopy
edited by David Cherns
Va/ume 204-Techniques and Concepts of High-Energy Physics V
edited by Thomas Ferbel
Va/ume 205-Nuclear Matter and Heavy Ion Collisions
edited by Madeleine Soyeur, Hubert Flocard,
Bernard Tamain, and Madeleine Porneuf
Series B: Physics
Techniques and Concepts
01 High-Energy
Physics V
Edited by
Thomas Ferbel
University of Rochester
Rochester, New York
Plenum Press
New York and London
Published in cooperation with NATO Scientific Affairs Division
Proceedings of the Fifth NATO Advanced Study Institute on
Technlques and Concepts of High-Energy Physics,
held July 14-25, 1988,
in St. Crolx, U.S. Virgin Islands
ISBN 978-1-4615-8003-4 ISBN 978-1-4615-8001-0 (eBook)
DOI10.1007/978-1-4615-8001-0
Library of Congress Cataloging in Publication Data
NATO Advanced Study Institute on Techniques and Concepts of High-Energy
Physics (5th: 1988: Saint Croix, V.I.)
Techniques and concepts of high-energy physics V I edited by Thomas
Ferbel.
p. cm-(NATO ASI series. Se ries S, Physics; v. 204)
"Proceedings of the Fifth NATO Advanced Study Institute on Techniques and
Concepts of High-Energy Physics, held July 14-25, 1988, in St. Croix, U.S. Virgin
Islands"-Verso of t.p.
"Published in cooperation with NATO Scientific Affairs Division."
Includes bibliographical references.
1. Particles (Nuclear physics)-Congresses. I. Ferbel, Thomas. 11. North Atlan
tic Treaty Organization. Scientific Affairs Division. 111. Title. IV. Series.
QC793.N38 1988 89-22990
539.7'2-dc20 CIP
© 1990 Plenum Press, New York
Softcover reprint of the hardcover 1s t edition 1990
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All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted
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PREFACE
The fifth Advanced Study Institute (ASI) on Techniques and Concepts
of High Energy Physics was held again at the Hotel on the Cay, in the
scenic harbor of Christiansted, St. Croix, U. S. Virgin Islands. The
ASI brought together a total of 71 participants, from 17 different
countries. It was another great success, due to the dedication of the
inspiring lecturers, the exceptional study body, and, of course, the
beautiful setting.
The primary support for the meeting was again provided by the
Scientific Affairs Division of NATO. The ASI was cosponsored by the
U.S. Department of Energy, by Fermilab, by the National Science
Foundation, and by the University of Rochester. A special
contribution from the Oliver S. and Jennie R. Donaldson Charitable
Trust provided an important degree of flexibility, as well as support
for worthy students from developing nations.
As in the ca se of the previous ASI's, the scientific program was
designed for advanced graduate students and recent PhD recipients in
experimental particle physics. The present volume of lectures should
complement the material published in the first four ASI's, and prove
to be of value to a wider audience of physicists.
It is a pleasure to acknowledge the encouragement and support that I
have continued to receive from colleagues and friends in organizing
this meeting. I am indebted to the members of my Advisory Committee
for their infinite patience and excellent advice. I am grateful to my
distinguished lecturers for their enthusiasm and participation in the
ASI, and, of course for their hard work in preparing the lectures and
providing the superb manuscripts for the proceedings. I thank Scott
Ogg of the West Indies Lab for his fascinating description of the
geology and marine life of St. Croix, and Albert Lang for talking him
into this. I thank Frederic Perrier for organizing the student
presentations. I also thank Earle Fowler, Bernard Hildebrand and Bill
Wallenmeyer for support from the Department of Energy, David Berley
for assistance from the National Science Foundation, and Leon Lederman
for providing me with access to the talents of Angela Gonzales at
Fermilab. At Rochester, I am indebted to Judy Mack, Sal Spinnichia,
and especially Connie Jones, for organizational assistance and typing.
I owe thanks to Andrew Pappas and the managers of the facilities at
the Hotel on the Cay, for their and their staff's hospitality and to
Margi Levy and her colleagues at Southerland Tours in Christiansted
who have been helping me for years with local arrangements. I wish to
acknowledge the generosity of Chris Lirakis and Mrs. Marjorie Atwood
of the Donaldson Trust, and support of George Blanar of LeCroy
Research Systems Corp. Finally, I thank Luis da Cunha of NATO for his
cooperation and confidence.
T. Ferbel
Rochester, New York
April 1989
v
LECTURERS
U. Amaldi CERN
J. Dorfan Stanford Linear Accelerator Center
G. Giacomelli University of Bologna
J. Harvey Rutherford Appleton Laboratory
L. Ibanez University of Madrid
G. Martinelli University of Rome
S. Peggs Central Design Group of the SSC
M. Regler Austrian Academy of Sciences
B. Winstein University of Chicago
SCIENTIFIC ADVISORY COMMITTTEE
M. Jacob CERN
R. Palmer Brookhaven National Laboratory
R. Peccei DESY
D. Perkins Oxford University
C. Quigg Central Design Group of the SSC and FNAL
P. Soding DESY
R. Taylor Stanford Linear Accelerator Center
M. Tigner Central Design Group of the SSC and Cornell University
SCIENTIFIC DIRECTOR
T. Ferbel University of Rochester
vi
CONTENTS
Aspects and the Physics of the Standard Model. . • . • • • . • . . •• 1
G. Martinelli
Grand Unification, Supersymmetry, Superstrings: An Introduction
to Physics Beyond the Standard Model . • • 59
L. Ibanez
zo Physics at the SLC. • • . • • . . • . . . • . • . • • . • . • • • • 117
J. Dorfan
Topics in Kaon Physics . . . • . . . . . . • • . • . . • . . . . • . • 173
B. Winstein
Post Collider Physics. • • • • • . • • . . . • • . • . . • . . . • • . 229
G. Giacomelli
Attaining Superhigh Energies with e+e- Collisions .•..•...••• 295
U. Amaldi
Nonlinear Dynamics in the SSC - Experiment E778 •.•..••.••.• 317
S. Peggs
Data Acquisition in High Energy Physics. . • • • • • . . • . . • • • • 347
J. Harvey
Reconstruction of Charged Tracks . . . . . . . . . • . . • • . . • • . 407
M. Regler and R. Frühwirth
Participants 501
Index .... 503
vii
ASPECfS OF THE PHYSICS OF THE STANDARD MODEL
Guido MARTINELLI
INFN -Istituto Nazionale Fisica Nuc1eare and
Dipartimento di Fisica, Universita di Roma "La Sapienza"
P.le A.Moro 2, 00185 Roma, Italy
ABSTRACf
Some selected aspects of the physics of the Standard Model are reviewed. In particular the
present status of the measurement of the basic parameters of the Standard Model and their
comparison with theoretical predictions, inc1uding radiative corrections, are discussed, together
with W and ZO physics at collider energies and hadron production of heavy flavours.
1. INTRODUCTION
In this series of lectures I have selected some aspects of the physics of the Standard
Model(1) which seemed to me of particular interest at the time of the St.Croix School.
Tbe Standard SU(2)xU(1) model has been so far spectacularly successfull. It has provideda
consistent picture of QED and of the Fermi theory of weak charged current interactions
(inc1uding parity violation, quark mixing, CP violation etc.) and predicted the weak neutral
current interaction and the existence and properties of the Wand ZO bosons. However all
physicists believe that the Standard Model cannot be the ultimate theory of nature since it leaves
too many questions unanswered. Inc1uding QCD the model has too many free parameters (~20)
and give no explanation for the existence of three distinct gauge couplings, the equality of the
proton and electron electromagnetic charge, the quark and lepton families, mixing angles and
masses. Furthermore it requires the fine tuning of some parameters (as the QCD 9-parameter) to
avoid conflict with experiments.
An important sector of the present and future experimental and theoretical work is to subject
the Standard Model to diverse and stringent tests to find indications on new physics and map
out the exc1uded domains. In sect.2 and 3 I will review the present test of the Standard Model,
inc1uding the effects of radiative corrections. Tbe physics of the W and ZO at collider energies,
where the Standard Model has found its more dramatic confirmation, will be discussed in sec.4.
In sect.5 I will review another subject, related to the physics of the Standard Model, i.e. the
theoretical and experimental aspects of the production of heavy flavours in hadronic collisions.
This subject is particularly relevant for the search of the top quark at CERN and FNAL and
important theoretical advances have been done in the last year.
In the course of the discussion other related topics, as upper limits on new quark/lepton
doublets, the production of extra W and Z heavy vector bosons or extra light neutrinos species
will be briefly discussed as complementary results to the tests of the Standard Model.
A more complete review of the physics beyond the Standard Model can be found in the
lectures of L.lbanez. The low energy phenomenology of weak interactions in kaon-decays, with
particular attention to CP violation, is discussed in the parallellectures by B.Winstein.
2. 1HE STANDARD MODEL
The standard model is a gauge theory which describes strong, weak and electro-magnetic
interactions. The model is based on a SU(3) group of colour, a SU(2) group of weak isospin
and a U(l) group of weak hypercharge. The SU(2)xU(1) symmetry is spontaneously broken
with the help of scalar mesons called Riggs scalars: in the resulting theory we find two charged
and one neutral massive bosons, W± and ZO, and one massless neutral vector boson, the
photon(l). The Lagrangian which describes the interaction of these vector bosons with fermion
fields is given by
weak charged currents weak neutral currents
(1) X; = *2 (J~ W~ + J~ W~) + g (J~ -sin2 8w J ~m.) ZIl +
"'J,i. cos 8w
electromagnetic currents
+ g sin 8w flim All '
Jt J
where are the weak-isospin currents, ~m. is the electromagnetic current, tg8w = g'/g and
g and g' are the couplings associated with the gauged SU(2) and U(l) group, respectively.
From eq.(l), it follows that
(2) e = g sin8w ,
where e is the electric charge. The currents in eq.(l) are given once the isospin and hypercharge
assignment offermions is known. To describe present phenomenology, we put the left-handed
fermions into isospin doublets:
2
1' 1'
(~~ ~~ (~l'
leptons,
g'l, '
(~'l (~'l'
(3) quarks,
j
In eq.(3) u, c, t are the charge + quarks and d', s', b' are related by a unitary transformation
t
to the mass eigenstate charge - d, sand b quarks. Right-handed fennions are weak-isospin
singlets.
W exchanges give rise to charged-current processes like, for example, the muon decay into
electron plus neutrinos:
This process is illustrated in fig. 1. Since the momentum trasfer Iq21« M;, the amplitude for
this process can be obtained by an effective Hamiltonian of the form
We can then relate the coupling g and the W mass to the Fenni constant Gp:
L
Gp _ M2 _ 1ta.
(6)
{2 - 8M;' w - {2 Gp sin2 Ow '
where a. is the fine-structure constant
Fig.1. -Relevant diagram for the muon decay. For Mw ~ 00, the diagram is described by an
effective four-fermion Hamiltonian.
3