Particle Physics: Cargèse 1989

361 Pages·1990·8.753 MB·English

by  Jean-Jacques Aubert (auth.), Maurice Lévy, Jean-Louis Basdevant, Maurice Jacob, David Speiser, Jacques Weyers, Raymond Gastmans (eds.)

Particle Physics
Cargese 1989
NATO ASI Series
Advanced Science Institutes Series
A series presenting the results of activities sponsored by the NA TO Science Committee,
which aims at the dissemination of 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 Sciences Berlin, Heidelberg, New York, London,
H Cell Biology Paris, and Tokyo
Recent Volumes in this Series
Volume 222-Relaxation in Complex Systems and Related Topics
edited by Ian A. Campbell and Carlo Giovannella
Volume 223-Particle Physics: Cargese 1989
edited by Maurice Levy, Jean-Louis Basdevant, Maurice Jacob,
David Speiser, Jacques Weyers, and Raymond Gastmans
Volume 224-Probabilistic Methods in Quantum Field Theory and Quantum Gravity
edited by P. H. Damgaard, H. HOffel, and A. Rosenblum
Volume 225-Nonlinear Evolution of Spatio-Temporal Structures in
Dissipative Continuous Systems
edited by F. H. Busse and l. Kramer
Volume 226-Sixty-Two Years of Uncertainty: Historical, Philosophical, and
Physical Inquiries into the Foundations of Quantum Mechanics
edited by Arthur I. Miller
Volume 227-Dynamics of Polyatomic Van der Waals Complexes
edited by Nadine Halberstadt and Kenneth C. Janda
Volume 228-Hadrons and Hadronic Matter
edited by Dominique Vautherin, F. Lenz, and J. W. Negele
Series B: Physics
Particle Physics
Cargese 1989
Edited by
Maurice Levy and Jean-Louis 8asdevant
Laboratory of Theoretical Physics and High Energies
Universite Pierre et Marie Curie
Paris, France
Maurice Jacob
Theory Division
CERN
Geneva, Switzerland
David Speiser and Jacques Weyers
Institute of Theoretical Physics
Universite Catholique de Louvain
Louvain-Ia-Neuve, Belgium
and
Raymond Gastmans
Institute of Theoretical Physics
Katholieke Universiteit Leuven
Leuven, Belgium
Plenum Press
New York and London
Published in cooperation with NATO Scientific Affairs Division
Proceedings of a NATO Advanced Study Institute on
Particle Physics,
held July 18-August 4, 1989,
in Cargese, France
ISBN-13: 978-1-4684-5792-6 e-ISBN-13: 978-1-4684-5790-2
DOl: 10.1007/978-1-4684-5790-2
© 1990 Plenum Press, New York
Softcover reprint of the hardcover 1st edition 1990
A Division of Plenum Publishing Corporation
233 Spring Street, New York, N.Y. 10013
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted
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PREVIOUS CARGESE SYMPOSIA PUBLISHED IN THE
NATO ASI SERIES B: PHYSICS
Volume 173 PARTICLE PHYSICS: Cargese 1987
edited by Maurice Levy, Jean-Louis Basdevant, Maurice Jacob,
David Speiser, Jacques Weyers, and Raymond Gastmans
Volume 156 GRAVITATION IN ASTROPHYSIGS: Cargese 1986
edited by B. Carter and J. B. Hartle
Volume 150 PARTICLE PHYSICS: Cargese 1985
edited by Maurice Levy, Jean-Louis Basdevant, Maurice Jacob,
David Speiser, Jacques Weyers, and Raymond Gastmans
Volume 130 HEAVY ION COLLISIONS: Cargese 1984
edited by P. Bonche, Maurice Levy, Phillippe Quentin, and
Dominique Vautherin
Volume 126 PERSPECTIVES IN PARTICLES AND FIELDS: Cargese 1983
edited by Maurice Levy, Jean-Louis Basdevant, David Speiser,
Jacques Weyers, Maurice Jacob, and Raymond Gastmans
Volume 85 FUNDAMENTAL INTERACTIONS: Cargese 1981
edited by Maurice Levy, Jean-Louis Basdevant, David Speiser,
Jacques Weyers, Maurice Jacob, and Raymond Gastmans
Volume 72 PHASE TRANSITIONS: Cargese 1980
edited by Maurice Levy, Jean-Claude Le Guillou, and
Jean Zinn-Justin
Volume 61 QUARKS AND LEPTONS: Cargese 1979
edited by Maurice Levy, Jean-Louis Basdevant, David Speiser,
Jacques Weyers, Raymond Gastmans, and Maurice Jacob
Volume 44 RECENT DEVELOPMENTS IN GRAVITATIONS: Cargese 1978
edited by Maurice Levy and S. Oeser
Volume 39 HADRON STRUCTURE AND LEPTON-HADRON INTERACTIONS: Cargese 1977
edited by Maurice Levy, Jean-Louis Basdevant, David Speiser,
Jacques Weyers, Raymond Gastmans, and Jean Zinn-Justin
Volume 26 NEW DEVELOPMENTS IN QUANTUM FIELD THEORY AND STATISTICAL
MECHANICS: Cargese 1976
edited by Maurice Levy and Pronob Mitter
Volume 13 WEAK AND ELECTROMAGNETIC INTERACTIONS AT HIGH ENERGIES:
Cargese 1975 (Parts A and B)
edited by Maurice Levy, Jean-Louis Basdevant, David Speiser,
and Raymond Gastmans
PREFACE
The 1989 Cargese Summer Institute on Particle Physics was
organized by the Universite Pierre et Marie Curie, Paris (M. Levy and
J.-L. Basdevant), CERN (M. Jacob), the Universite Catholique de Louvain
(D. Speiser and J. Weyers) and the Katholieke Universiteit te Leuven
(R. Gastmans), which, since 1975, have joined their efforts and worked
in common. It was the twenty-sixth Summer Institute held at Cargese and
the tenth organized by the two Institutes of Theoretical Physics at
Leuven and Louvain-la-Neuve.
The 1989 school centered on the following topics
- new experimental results
- strings, superstrings and conformal field theory
- lattice approximations.
Of the many new experimental results, we would like to mention
especially those from SLAC presented by Professor G. Feldman. On the
other hand, we had the tantalizing knowledge that LEP would begin to
operate only right after the end of the school!
For this we received ample replacement: Professor J. Steinberger
summed up all major CP violation experiments done to date and commented
upon them. The reader will find also various other most interesting
contributions, for instance on high energy ion beams. Once more
theoreticians and experimentalists (this time more than usual) came
together to discuss high energy particle physics.
We owe many thanks to all those who have made this Summer
Institute possible!
Special thanks are due to the Scientific Committee of NATO and
its President for a generous grant. We are also very grateful for the
financial contributions given by the French Ministry of Foreign Affairs
and the Institut National de Physique Nucleaire et de Physique des
Particules.
We also want to thank Ms. M.-F. Hanseler for her efficient
organizational help, Mr. and Ms. Ariano for their kind assistance in
all material matters of the school, and, last but not least, the people
from Cargese for their hospitality.
Most of all, however, we would like to thank all the lecturers
and participants : their commitment to the school was the real basis
for its success.
M. Levy R. Gastmans
J.-L. Basdevant D. Speiser
M. Jacob J. Weyers
vii
CONTENTS
Phys ics at LEP .................................................. .
J.-J. Aubert
Physics at SLC 25
G. Feldman
Physics in pp collisions ......................................... 47
F. Pauss
Physics with Righ Energy Ion Beams ............................... 79
P. Sonderegger
Electroweak Interactions and LEP/SLC Experiments ................. 97
G. Altarelli
The Geometrical Principles of String Theory Constructions ........ 141
J. Govaerts
Two Topics in Quantum Chromodynamics ............................. 217
J.D. Bjorken
Radronic Matrix Elements and Weak Decays ~n Lattice QCD .......... 239
G. Martinelli
Experimental Status of CP Violation ...•.......................... 297
J. Steinberger
Lee-Wick Model and Soliton Stars ................................. 335
R. Vinh Mau
Gluon Confinement ~n Chromoelectric Vacuum ....................... 343
R. Basu
Mean Field Theory and Beyond for Gauge-Riggs-Fermion Theories .... 353
S.W. de Souza
Index............................................................ 357
ix
PHYSICS AT LEP
Jean-Jacques Aubert
Centre de Physique des Particules de Marseille,
I N2 P3-CNRS/Universite d'Aix-Marseille II, 70 route
Leon-Lachamp, Case 907, F-13288 Marseille Cedex 9, France
I - INTRODUCTION
By the time of the school the commissioning of LEP was just
starting and obviously there were no physics results, not even a
single ZO event. The first events have been observed since then in
August.
Sp "physics at LEP" was still "Monte Carlo physics". As
Altarelli covered also part of the topics, I limit myself to specific
points of physics as the Z width measurements, the higgs detection,
QCD and B physics.
II - DETECTORS AT LEP
There are four detectors : Aleph, Delphi, L3 and Opal installed
respectively on pit 4,8,2,6. They are in place, more or less ready to
take data.
The properties of the detectors have been described extensively
in many places1, Aleph has a good space resolution for the
electromagnetic calorimeter, Delphi has Rich counters for particle
identification, L3 has good energy resolution on leptons and Opal is
a rather more conventional detector. Anyhow, being so close from the
point where physics results will come out, the readiness and the
skill of physicist will probably make more difference than detector
design.
III - THE WIDTH OF THE Z
- In the standard model
r z r r r"( r
= Nllr II + e + jJ + + had
Particle Physics: Cargese 1989
Edited by M. Levy et at.
Plenum Press. New York, 1990
rz= 2570 MeV with rU 102 x 3 MeV (quark with charge 2/3)
rd 131 x 3 MeV (quark with charge 1/3)
r e r tJ = r'C = 86 MeV
r IJ 170 MeV
So a new quark, a new charged lepton or a new neutrino will
r
increase Z in a known way (provided than mnew < mz/2)
- In supersymmetric models, the ZO can decay in a pair of
charged higgsinos or winos
+ - 0 -+--
e e -> Z -> W W
-+--
0
Z -> H H
The contribution to an increase of the Z width can be large
800 MeV for winos, around 100 MeV for higgsinos or smaller
depending on the precise model.
- In composite models as shown by F.M.Renard and F.Boudjema2 W
and Z are no more true gauge bosons. There may exist a composite
boson sector with a rich spectrum of spin, flavour, color, states,
scalars and vectors (isoscalar Y, excited Z*) .
Even with very high mass (much larger than mZ)' mixing effects
with the ZO modify its mass and coupling, it also affects the ZO
width and can give a decrease of r z. This effect may contribute to
a srz of the order of plus or minus 70 MeV.
So any deviation from the width of the standard model will be
an indication for new physics and I am sure that it will then be
easy to understand its origin.
As shown by Altarel1i in the school, the theoretical
calculation of the line shape is well under control in the standard
model ; the radiative correction and the electroweak correction are
computable.
IV - SENSITIVITY ON NEUTRINO COUNTING
They are many ways of computing the neutrinos species
available at the ZO peak3, I will restrict myself to two approaches
- Total width measurement : as we have seen
r z = NlJr IJ + 3 r I + r had
(rzmeas _ r SM) / r SM
Z IJ'
2
~NV : number of neutrinos species
rzmeas : width of the z measured
r zSM : width of the Z calculated in the standard model
rvSM : width induced by one neutrino species computed in the
standard model
Since only r z is measured one needs only a pulse to pulse
luminosity determination (not an absolute one). It is expected to
be as good as 1%.
with 3pb-1 105Z), the error on the total width will be
around 30 MeV, the statistical error 20 MeV being smaller than the
systematic one : 25 MeV.
rv
With = 170 MeV, ~NV will be around 0.2.
- Invisible width as shown by Gary Feldman4
and
rinvisible
One measures opeak~~. This requires an absolute knowledge of the
luminosity. r~ is computed in the standard model, Nhad/N~~ is
measured, does not need any luminosity determination but the
knowledge of efficiency, acceptance and background.
. How well Nhad can be measured
Nhad = (l/EhadEtdg) (nobs - LObackl Ebackl - ... )
where E are efficiencies, 0backl are cross section for
background 1, L the luminosity.
+ (nbackl /nobs) 2 ( (~L/L) 2+ (~O backl/ 0backl) 2 + (~Ebackl /Ebackl) 2 )
+ ...
3