Table Of ContentPHYSICS IN
COLLISION
High-Energy ee/ep/pp Interactions
Volume 2
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PHYSICS IN
COLLISION
High-Energy ee/ep/pp Interactions
Volume 2
Edited by
PER CARLSON
University of Stockholm
Stockholm, Sweden
and
W. PETER TROWER
Virginia Polytechnic Institute and State University
Blacksburg, Virginia
PLENUM PRESS • NEW YORK AND LONDON
The Library of Congress cataloged the first volume in this series as follows:
Main entry under title:
Physics in collision.
"Proceedings of an International Conference on Physics in Collision, High·Energy
ee/ep/pp Interactions, held May 28-31, 1981, in Blacksburg, Virginia"-Verso t.p.
Includes bibliographical references and indexes.
1. Nuclear reactions-Congresses. 2. Lepton interactions-Congresses. 3. Quarks
Congresses. I. Trower, W. Peter. II. Bellini, Gianpaolo. III. International Conference on
Physics in Collision: High·Energy ee/ep/pp Interactions (1981: Blacksburg, Va.)
QC794.8.H5P48 539.7'54 82·620
AACR2
ISBN 978-1-4684-8467-0 ISBN 978-1-4684-8465-6 (eBook)
DOl 10.10071978-1-4684-8465-6
Proceedings of an International Conference on Physics in Collision: High.Energy
ee/ep/pp Interactions, held June 2 - 4, 1982, in Stockholm, Sweden
© 1983 Plenum Press, New York
Softcover reprint of the hardcover 1s t edition 1983
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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recording, or otherwise, without written permission from the Publisher
PREFACE
The field of particle physics is developing very rapidly.
During this past year, physicists added a new instrument to their
arsenal for the study of quark-quark, quark-lepton, and lepton
lepton interactions. This machine, the PROTON-ANTIPROTON COLLIDER,
achieved the highest energy in the world. With its five detectors,
it is beginning to explore hitherto inaccessible regions for new
physics (Section I). Lepton-Iepto~ machines with detectors at full
efficiency are producing copious data of the very highest precision.
The possibility of glueballs and the detailing of the properties of
the upsilon family have been of major importance this year (Section
II). The particle jets which are believed to be direct manifesta
tions of the quark structure of matter continue to provide valuable
data against which we can test the ideas of QCD (Section III). With
the advent of more and better data it is now possible to study in
detail the formation evolution of hadronic states. Especially
interesting are the properties of heavy quark states (Section IV).
A far-seeing look into the future development of any fecund scienti
fic field is rarely accurate, but is always stimulating (Section V).
It is against this background of participating in the clarifi
cation of the Physics in Collision that we continue this series.
The editors on behalf of the conferees wish to respectfully
dedicate this second volume of PHYSICS IN COLLISION to Professor
Gosta Ekspong of the University of Stockholm on the occasion of his
60th year. We appreciate his lively interest in our physics, his
long international leadership in our discipline, and the way his
person enriches our lives.
Per Carlson W. Peter Trower
Stockholm, Sweden Blacksburg, Virginia USA
v
CREDITS
The Second International Conference on Physics in Collision
was held at the Wenner-Gren Center in Stockholm, Sweden, June 2-4,
1982. The financial support, obtained from the Swedish Natural
Science Research Council and the Royal Swedish Academy of Sciences
through its Nobel Committee for Physics, is gratefully acknowledged.
The main speakers, whose contributions are included in these
proceedings, provided an excellent up-to-date platform for further
discussions among the participants. In planning the scientific
program the initiatives and views of the International Advisory
Committee was of decisive importance.
Without the enthusiasm and diligence of Per Carlson, it would
not have been possible to carry through the work of the Conference
succ~ssfully. He deserves my sincerest thanks as do all of his
local staff, among them Ann-Margret Hildeman who served throughout
the planning and running of the Conference in an excellent way.
The preparation of the proceedings by Cheryl Bowman was supported
in part by the U.S. National Science Foundation and the U.S.
Department of Energy.
Gosta Ekspong, University of Stockholm (Chairman)
ADVISORY COMMITTEE
Gianpaolo Bellini, University of Kenneth Moffeit, SLAC
Milan Lucien Montanet, CERN
Karl Berkelman, Cornell Jan Nilsson, University of
University Gothenburg
Per Carlson, University of Carlo Rubbia, CERN
Stockholm John Rushbrooke, Cambridge
Richard Dali tz, Oxford Univ ersi ty University
Gerson Goldhaber, UC Berkeley Bengt Svensson, University of Lund
Maurice Jacob, CERN Kasuke Takahashi, KEK
Sven Kullander, University of Samuel Ting, MIT
Uppsala Peter Trower, Virginia Tech
Hannu Miettinen, University of Gustav Weber, DESY
Helsinki Gunter Wolf, DESY
LOCAL COMITTEE
Per Carlson, Secretary
Sigward Nilsson
Narendra Yamdagni
vii
CONTENTS
SECTION I: pp/pp COLLISIONS
Hard Scattering at ISR Energies . • . . . . • . 1
N. A. McCubbin
Comparison of pp/pp Interactions at the ISR . • • . • • . .. 21
M. Jacob
First Results of the UAl Experiment • . . • . . . . • • . .. 43
M. Pimia
Status and First Results from the UA2 Experiment 67
P. Jenni
Proton-Antiproton Elastic Scattering and Total Cross Section
at the CERN Collider . . . • . . • . . . . . . . . .• 85
Bert Koene
Results from the UA5 Experiment . . . . . . . . . . . . . .. 99
D. R. Ward
+ -
SECTION II: e e COLLISIONS
A Review of Two-Photon Physics 123
Susan Cooper
Gluonium and QCD Effects in the J/~ Region 149
Elliott D. Bloom
The Upsilon Resonances--Recent Results 179
M. G. D. Gilchriese
+ -
Electroweak Effects in e e Annihilations . • • . . . . . • .. 213
B. Naroska
ix
x CONTENTS
SECTION III: JETS
Jets at PETRA . . 233
Horst Oberlack
Recent Results from the MAC and MARK II Detectors at PEP 273
Jonathan Dorfan
The Dynamics of a Fragmentation Model or a Possible
Life after the Parton Stage • . . . . . • . . 303
Bo Andersson
SECTION IV: STRUCTURES IN HADRONIC INTERACTION AND HEAVY FLAVORS
Event Structure in Collider and Cosmic Ray Experiments 327
N. Yamdagni
+ -
QCD and the Space-Time Evolution of High-Energy e e ,
pp, and Heavy Ion Collisions . . . . • . 343
J. D. Bjorken
Hadronic Production of Heavy Flavours . 369
L. Montanet
+ -
The Decay of Heavy Flavor States in e e Annihilations 387
Thomas A. Ferguson
SECTION V: OVERVIEW
Is There a Desert Beyond the Mountains? . • 405
C. H. Llewellyn Smith
Participants 421
Index . . . . . . . . . • • • . • • . • . . • . • . . • . . • 431
HARD SCATTERING AT ISR ENERGIES
N. A. McCubbin*
Rutherford Appleton Laboratory
Chilton, Didcot, OXON OXll O~X
England
INTRODUCTION
This is a written version of a talk given at the June 1982
Stockholm conference on Physics in Collisions.
After giving an extremely brief summary of the situation in
hard scattering in hadron-hadron collisions, I shall then discuss
in more detail some of the recent results from:
a) Di-lepton production (Drell-Yan),
b) Single photon production,
c) Experiments using a high PT single particle trigger, and
d) Experiments using a calorimeter trigger.
Finally, there are some concluding remarks.
BRIEF SUMMARY OF HARD SCATTERING IN HADRON
HADRON COLLISIONS
Over the last decade, hard scattering has come to mean those
processes in which the primary interaction involves two hadronic
constituents.
Thus, at the constituent level we envisage diagrams like:
2
N.A. McCUBBIN
a) y
g
Diagram a) represents the Drell-Yan process of di-lepton production,
oJ is one of the diagrams contributing to high PT hadron production,
and c) is one of the high PT single photon diagrams.
It is not unjust to remark that experiments at the ISR have
been the major contributors to the last two processes.
This constituent picture of deep inelastic processes makes
certain predictions (e.g., scaling, angular distribution, high PT
jets, etc.) which are too well known to need any detailed discussion
here. So I shall simply summarize the status of the three processes
mentioned above from the standpoint of constituent scattering:
Drell-Yan (h + h + 1 + I + X)
Scaling (dcr/dM = 1/M3 • F(T» OK
Absolute magnitude of da/dM Experiment is a factor of -2
higher than (naive) theory.
(The "K" factor)
Angular distribution (1 + cos2e) OK
lB.
<PT> of di-lepton system Rises with M~I and QeD
likes this.
Dependence of cross-section on a. = 1
Atomic no. (Aa.)
One should add that the Drell-Yan process affords the possibility
of measuring structure functions of ~, K, and p's. (p and n
structure functions are, of course, measured in deep-inelastic
lepton/neutrino scattering.)
In general the theoretical predictions, which come as much
from the naive quark-parton model as QeD. are in good agreement
with experiments. The magnitude of the cross-section is the out
standing problem •. It should be noted that the recent QeD literature
raises some doubts about the validity of the "factorization theorem"
because of initial state interactions, and this may have some
bearing on this problem.1
