ECFA 84/85 CERN 84-10 5 September 1984 LARGE HADRON COLLIDER IN THE LEP TUNNEL Vol. II PROCEEDINGS OF THE ECFA-CERN WORKSHOP held at Lausanne and Geneva, 21-27 March 1984 ©Copyright CERN, Genève, 1984 Propriété littéraire et scientifique réservée pour Literary and scientific copyrights reserved in ail tous les pays du monde. Ce document ne peut countries of the world. This report, or any part of être reproduit ou traduit en tout ou en partie sans it, may not be reprinted or translated without l'autorisation écrite du Directeur général du written permission of the copyright holder, the CERN, titulaire du droit d'auteur. Dans les cas Director-General of CERN. However, permission appropriés, et s'il s'agit d'utiliser le document à will be freely granted for appropriate non• des fins non commerciales, cette autorisation commercial use. sera volontiers accordée. 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CERN - Service d'Information scientifique - RD/650 - 3000- novembre 1984 - iii - ABSTRACT A Workshop, jointly organized by ECFA and CERN, took place at Lausanne and at CERN in March 1984 to study various options for a pp (or pp) collider which might be installed at a later data alongside LEP in the LEP tunnel. Following the exploration of e+e" physics up to the highest energy now foreseeable, this would open up the opportunity to investigate hadron collisions in the new energy range of 10 to 20 TeV in the centre of mass. These proceedings put together the documents prepared in connection with this Workshop. They cover possible options for a Large Hadron Collider (LHC) in the LEP tunnel, the physics case as it stands at present, and studies of experimental possibilities in this energy range with luminosities as now considered. - iv - Organizing Committee G. Brianti, CERN; W. Hoogland, NIKHEF M. Jacob, CERN; C. Joseph, Lausanne J. Mulvey, Oxford; C. Rubbia, CERN J. Sacton, Brussels Workshop Secretariat Ch. Petit-Jean-Genaz CERN/LEP - v - FOREWORD The first part of the Workshop on the Feasibility of Hadron Colliders in the LEP Tunnel took place at the Dorigny Campus of the University of Lausanne. It lasted four days and brought together close to 150 participants. The second part was a one-and-a-half day meeting held at CERN, immediately following upon the Lausanne meeting, and during which the conclu• sions were presented to and debated by a very large audience of physicists and engineers. The installation of a hadron collider in the LEP tunnel, using superconducting magnets, has always been foreseen as the natural long-range extension of the CERN facilities beyond LEP. The recent successes of the CERN pp Collider now give us confidence that such a large hadron collider would be an ideal machine for exploring physics in the few TeV range at the constituent (quarks and gluons) level — an energy domain which the very success of the Standard Model, based on the SU(2) x U(l) x SU(3) gauge symmetry of the electroweak and strong interactions, leads us to consider as being crucial for a deeper understanding. Whilst the installation of a large hadron collider in the LEP tunnel may at present be considered as a rather remote possibility, the design of the high-performance magnets which we would like to use for such a machine still demands a great amount of research and deve• lopment; this indeed appears as a prerequisite for the definition of the parameters of such a project. A Workshop bringing together theorists, experimentalists, accelerator physicists, and also experts in superconducting magnets was thus deemed timely. Although the Workshop proper was rather short, it was actively prepared by different Working Groups dealing with various facets of the whole scheme. A large amount of work was thus invested in the Workshop, and its outcome can be seen in these Proceedings, which are presented in two volumes. This two-volume structure was adopted in order to make at least part of the material available at the earliest possible date — rather than, as initially planned, to put into the first volume the texts of the talks presented during the open meeting at CERN, which in fact concluded the Workshop. The table of contents now covers both Volume I and Volume II. At the beginning of Volume II we find the part of the proceedings of the CERN meeting which were not available for inclusion in Volume I and, in particular, the reports of the Working Groups on Electron-Photon Identification and on Data Acquisition. However, in order to strike the right key note, we actually start Volume II with the concluding remarks presented by C. Rubbia at the end of the CERN meeting. Next to the two reports from experimental working groups, which logically should have followed Chapter IV and Chapter VI, respectively, we find a series of theoretical contribu• tions which were presented at Lausanne. This starts with the report of J. Ellis, G. Gelmini and H. Kowalski, 'New particles and their experimental signatures', which served as a general - vi - introduction to collider physics at Lausanne and is thus singled out as Chapter XII. These theoretical contributions altogether review in great detail the topical questions and expec• tations concerning collider physics in the multi-TeV range, which were summarized by Ch. Llewellyn Smith in his report at CERN (Chapter I). Two of the reports presented at Lausanne were already included in Volume I. These are in Chapter IX, which reviews Composite Models. (Logically, Chapter IX should be combined with Chapter XIII.) We then move to physics issues which are potentially very interesting but which take us away from hadron-hadron interactions in the collider mode. The potential of ep collisions, as in principle accessible with LEP and a hadron collider in the same tunnel, is reviewed by G. Altarelli, B. Meie, and R. Riickl. The rather intense, very high energy neutrino beams, which one could obtain (for free) from the abundant production of charmed particles, open up very interesting possibilities, as discussed by A. De RÚjula and R. Rückl. With the material thus put together, one finds a thorough discussion of collider physics in the multi-TeV range, as it is foreseen today. We conclude these proceedings with the brilliant address of G. 't Hooft, 'Prospects of theoretical particle physics', which concluded the CERN meeting. The Organizing Committee would like to express its thanks to those people in various sections of the CERN Documentation Department, whose conscientious work brought these Proceedings to their present form. M. Jacob, CERN Editor - vii - CONTENTS Volume I Page FOREWORD vii SUMMARY REPORT, The Organizing Committee 1 WELCOME ADDRESS, H. Schopper 19 INTRODUCTION, J. Sacton 21 CHAPTER I: THE PHYSICS CASE 25 Physics with a multi-TeV hadron collider, C.H. Llewellyn Smith 27 CHAPTER II: A FEASIBILITY STUDY OF POSSIBLE MACHINE OPTIONS, A. Asner et al. 49 11.1 Review of possible options 51 11.2 The pp option 53 11.3 The pp option 116 11.4 Final remarks and conclusions 117 CHAPTER III: THE SUPERCONDUCTING SUPER COLLIDER 143 Status report on the SSC, H. Gründer 145 CHAPTER IV: JET DETECTION 165 Jets at the Large Hadron Collider, The LHC Jet Study Group 167 CHAPTER V: MUON DETECTION 209 V.l Muon Group report, A. Ali et al. 211 V.2 Unconventional methods for muon momentum measurements, C. Goessling and C. ZuparièiG 223 V.3 Muon momentum measurement in magnetized iron spectrometers, R. Voss and C. Zupanaic 228 V.4 Muon identification and muon trigger, K. Eggert et al. 238 CHAPTER VI: TRIGGERING 243 Status report, The Trigger Working Group 245 CHAPTER VII: TRACKING CHAMBERS AND VERTEX DETECTION 265 VI1.1 Tracking detectors for a Large Hadron Collider, A. Wagner 267 VI 1.2 Report of the Vertex Detector Working Group, G. Bellini and P.G. Rancoita 282 VII.3 Low-noise electronics for experiments at LHC. Design suggestions, P.F. Manfredi 292 VI 1.4 Superconducting tunnel junctions as radiation detectors, A. Barone et al. 298 - vin - CHAPTER VIII: FORWARD PHYSICS VIII. 1 Total cross-section and diffractive processes at the Large Hadron Collider, M. Eagv.enav.ev and G. Mattiae VIII.2 Production of masses in the forward cone — The "angle of archeology", T. Ekelöf VIII.3 Theoretical predictions for pp and pp elastic scattering in the TeV energy domain, C. Bourrely and A. Martin CHAPTER IX: TWO THEORETICAL TALKS IX.1 Compositeness: the supercollider frontier, R.D. Peaaei IX.2 Lepton and quark substructure at a multi-TeV collider, H. Fritzsch LIST OF PARTICIPANTS Volume II FOREWORD CONCLUDING REMARKS, C. Rubbia CHAPTER X: IDENTIFICATION OF ELECTRONS AND PHOTONS X.l Electron and photon identification, The Electron-Photon Group, presented by P. Bloch X.2 Electron identification using transition radiation, D. Froidevaux X.3 Identification of single photons, L.