1he Subnuclear Series • Volume 38 Proceedings of the International School of Subnuclear Physics THEORY AND EXPERIMENT HEADING FOR NEW PHYSICS THE SUBNUCLEAR SERIES Series Editor: ANTONINO ZICmCm, European Physical Society, Geneva, Switzerland 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 30 1992 31 1993 32 1994 33 1995 34 1996 35 1997 36 1998 37 1999 38 2000 STRONG, ELECfROMAGNETIC, AND WEAK INTERACTIONS SYMMETRIES IN ELEMENTARY PARTICLE PHYSICS RECENT DEVELOPMENTS IN PARTICLE SYMMETRIES STRONG AND WEAK INTERACfIONS HADRONS AND THEIR INTERACfIONS THEORY AND PHENOMENOLOGY IN PARTICLE PHYSICS SUBNUCLEAR PHENOMENA ELEMENTARY PROCESSES AT HIGH ENERGY PROPERTIES OF THE FUNDAMENTAL INTERACTIONS HIGHLIGHTS IN PARTICLE PHYSICS LAWS OF HADRONIC MATTER LEPTON AND HADRON STRUCTURE NEW PHENOMENA IN SUB NUCLEAR PHYSICS UNDERSTANDING THE FUNDAMENTAL CONSTITUENTS OF MATTER THE WHYS OF SUB NUCLEAR PHYSICS THE NEW ASPECTS OF SUB NUCLEAR PHYSICS POINTLIKE STRUCTURES INSIDE AND OUTSIDE HADRONS THE HIGH-ENERGY LIMIT THE UNITY OF THE FUNDAMENTAL INTERACTIONS GAUGE INTERACTIONS: Theory and Experiment HOW FAR ARE WE FROM THE GAUGE FORCES? QUARKS, LEPTONS, AND THEIR CONSTITUENTS OLD AND NEW FORCES OF NATURE THE SUPERWORLD I THE SUPERWORLD II THE SUPERWORLD III THE CHALLENGING QUESTIONS PHYSICS UP TO 200 TeV PHYSICS AT THE HIGHEST ENERGY AND LUMINOSITY: To Understand the Origin of Mass FROM SUPERSTRINGS TO THE REAL SUPERWORLD FROM SUPERSYMMETRY TO THE ORIGIN OF SPACE-TIME FROM SUPERSTRING TO PRESENT-DAY PHYSICS VACUUM AND VACUA: The Physics of Nothing EFFECTIVE THEORIES AND FUNDAMENTAL INTERACTIONS HIGHLIGHTS OF SUBNUCLEAR PHYSICS: 50 Years Later FROM THE PLANCK LENGTH TO THE HUBBLE RADIUS BASICS AND HIGHLIGHTS IN FUNDAMENTAL PHYSICS THEORY AND EXPERIMENT HEADING FOR NEW PHYSICS Volume I was published by W A Benjamin, Inc., New York; 2-8 and 11-12 by Academic Press, New York and London; 9-10 by Editrice Compositori, Bologna; 13-29 by Plenum Press, New York and London; 30-38 by World Scientific, Singapore 1he Subnuclear Series • Volume 38 Proceedings of the International School of Subnuclear Physics THEORY AND EXPERIMENT HEADING FOR NEW PHYSICS Edited by Antonino Zichichi European Physical Society Geneva, Switzerland Published by World Scientific Publishing Co Pte Ltd POBox 128, Farrer Road, Singapore 912805 USA office: Suite IB, 1060 Main Street, River Edge, NJ 07661 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE Library of Congress CataIoging-in-Publication Data International School of Subnuclear Physics (38th: 2000 : Brice, Italy) Theory and experiment heading for new physics: proceedings of the International School of Subnuclear Physics I edited by Antonino Zichichi p em (The subnuclear series; v 38) ISBN 9810247931 Particles (Nuclear physics) Congresses Gauge fields (Physics) Congresses Zichichi, Antonino II Title III Series I QC793 1555 2000 2001053628 British Library CataIoguing-in-Publication Data A catalogue record for this book is available from the British Library Copyright © 2001 by World Scientific Publishing Co Pte Ltd All rights reserved This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA In this case permission to photocopy Printed is not required from the publisher in Singapore by Uta-Print v PREFACE During August/September 2000, a group of 80 physicists from 53 laboratories in 15 countries met in Erice to participate in the 38th Course of the International School of Subnuclear Physics The countries represented by the participants were: Algeria, Australia, Brazil, Bulgaria, China, Denmark, France, Germany, Greece, India, Iran, Italy, Japan, the Netherlands, Peru, Poland, Russia, Spain, Switzerland, Taiwan, the United Kingdom, Ukraine and the United States of America The School was sponsored by the Academies of Sciences of Estonia, Georgia, Lithuania, Russia and Ukraine; the Chinese Academy of Sciences; the Commission of the European Communities; the European Physical Society (EPS); the Italian Ministry of University and Scientific Research (MURST); the Sicilian Regional Government (ERS); the Weizmann Institute of Science; the World Federation of Scientists and the World Laboratory The purpose of the School was to focus attention on the theoretical investigation of several basic unity issues, including: i) The understanding of gauge theories both in their continuum and in their lattice versions: ii) The possible existence and relevance of large extra dimensions together with the resulting lowering of the Planck/string scale down to the TeV range; iii) The origin and structure of flavour mixing in the quark and lepton (neutrino) sectors, as reported in the contents A new feature of the School, introduced in 1996, is a series of special sessions devoted to "New Talents" This is a serious problem in Experimental Physics where collaborations count several hundreds of participants and it is almost impossible for young fellows to be known Even if with much less emphasis the problem exists also in Theoretical Physics So we decided to offer the young fellows a possibility to let them be known Eleven "new talents" were invited to present a paper, followed by a discussion Three were given the prize: one for the best presentation; one for an original theoretical work; and one for an original experimental work These special sessions devoted to New Talents represent the projection of Subnuclear Physics on the axis of the young generation As every year, the discussion sessions have been the focal point of the School's activity vi During the organization and the running of this year's Course, I enjoyed the collaboration of two colleagues and friends, Gerardus 't Hooft and Gabriele Veneziano, who shared with me the Directorship of the Course I would like to thank them, together with the group of invited scientists and all the people who contributed to the success of this year's Course I hope the reader will enjoy the book as much as the students attending the lectures and discussion sessions Thanks to the work of the Scientific Secretaries, the discussions have been reproduced as faithfully as possible At various stages of my work I have enjoyed the collaboration of many friends whose contributions have been extremely important for the School and are highly appreciated I thank them most warmly A final acknowledgement to all those in Erice, Bologna and Geneva, who have helped me on so many occasions and to whom I feel very indebted Antonino Zichichi Geneva, October 2000 vii CONTENTS Opening Lecture From Reductionism to Holism T D Lee Mini-Courses on Basics Chiral Gauge Theories Revisited 41 M Luscher Strings, Branes and New Physics 90 J Polchinski New Physics from New Dimensions 139 A ntoniadis Flavour Dynamics: CP Violation and Rare Decays 200 A J Buras Hot Issues Round Table on Status of g' / g About the Measurement of Direct CP Violation at CERN with the NA48 Experiment 338 M Calvetti Principles Behind the KTe V Approach to Measuring Direct CP Violation 341 B Winstein Tests of T-Invariance in Neutral Kaon Decays 357 P K K abir With Grand Unification Signals in, Can Proton Decay Be Far Behind? 375 J C Pati Experimental Experimental Highlights Highlights from LEP U Becker 416 vii Experimental Highlights from the HERA Collider G Wolf 455 CP Violation and Other Cosmological Issues B Winstein 512 Experimental Highlights from Super-Kamiokande Y Totsuka 533 Experimental Highlights from AMS S C C Ting 570 Special Sessions for New Talents Searching for Massive Exotic Particles in the NuTeV Neutrino Detector J A Formaggio 577 Ultradense Quark Stars from Perturbative E S Fraga 596 QCD The Charged-Mode Systematic Error for the KTeV Experiment J Graham 604 From Minimal to "Realistic" Supersymmetric Masina 609 A Non-Technical Introduction M Schwartz SU(5) Grand Unification to Extra Dimensions 619 Casimir Scaling as a Test of QCD Vacuum V Shevchenko 627 637 Measurement of the Mass of the W Boson at LEP and Determination Electroweak Parameters A Straessner of 647 Closing Lecture The Discovery of the Renormalizability G 't Hooft of Non-Abelian Gauge Theories 656 ix Closing Ceremony Prizes and Scholarships 670 Participants 672 Introduction The quantum hypothesis put forward by Max Planck in 1900 sparked a revolution in physics which led to the discovery of quantum mechanics in 1925 Without quantum mechanics, much of the twentieth century's scientific civilization would not be here today, and that includes our present knowledge of atomic and molecular structure, semiconductors, laser, superconductivity, super-computers and many others Just one year before Planck's discovery of h, in 1899, J J Thomson was able to determine that the electric charge has to be in units of e (= 6.8 x W-w esu), and hence the discovery of the electron These discoveries forged physics in the last century into a quest for the increasingly small We believed through studying the smallest things, understanding "reductionism" of all larger ones would naturally follow The dominance of such is further reinforced by our ability to make precise predictions based on quantum theory, and accurate measurements through experiments This reductionism approach has culminated in our successful discoveries that all known matter is composed of 12 elementary particles, six quarks and six leptons However, as shown in Fig I, the dichotomy between the symmetry in our theories and its violations in our observations, and the puzzle of quark-confinement force us to treat the physical vacuum as an independent macroscopic medium, which embeds the microscopic world of elementary particles At present, we are poised at the threshold of a new revolution in physics, moving from "reductionism" to "holism." In what follows, I will discuss some of the experimental and theoretical tools that may prove useful in carrying out the first stage of this revolution 578 with mixing, or via R-parity violating supersymmetric processes High energy neutrino beamlines are ideal places to produce N° particles, since very large numbers of protons interact in these beamlines NO's may be produced via a number of mechanisms, including primary interactions of the protons either in the target or the beam dump, through prompt decays of charmed or bottom mesons, by decays of pions or kaons in the decay region, or in neutrino interactions in the shielding downstream of the decay region A particle detector placed downstream of this sort of beam line (Le., in the neutrino beam itself) can be used to search for N° decays We report here the results of a search for N° particles in the mass region above 2.2 GeV I which decay into final states with at least one muon and one other charged particle For the search described here, the NuTeV neutrino beamline was used in conjunction with a low mass decay detector called the decay channel NuTeV has previously reported results of searches for NO's in the mass region between 0.25 to 2.0 GeV Ic2 with at least one final state muon [5], and in the mass region below 0.25 GeV I c2 for decays to electrons [6] The 0.25 to 2.0 GeV I c2 study addressed NHLs that could be produced in the decay of K and D mesons The low mass « 0.3 GeV I 2) study was pursued mainly to address the KARMEN timing anomaly [7], which has been interpreted as a N° particle with a mass equal to 33.9 MeV/c2• NuTeV has now extended its search to particles whose masses lie above 2.2 GeV Ic2 II THE BEAMLINE AND DETECTOR During the 1997 fixed-target run at Fermilab, NuTeV received 2.54 x 1018 800 GeV Ic protons with the detector configured for this search The proton beam was incident on a one-interact ion-length beryllium oxide target at a targeting angle of 7.8 mr with respect to the detector A sign-selected quadrupole train (SSQT) [8] focused either positive (for 1.13 x 1018 protons) or negative (for 1.41 x 1018 protons) secondary 7r and K mesons into 579 a 440 m evacuated decay region pointed towards the NuTeV decay channel and neutrino detector hall Surviving neutrinos (and possibly also NO's) traversed , ,850meters of earthberm shielding before reaching the NuTeV decay channel The decay channel region (Figure 1), located 1.4 km downstream of the production target, was designed to contain minimal material (in order to suppress neutrino interactions) and to have tracking sufficient to isolate two-track decays of neutral particles A 4.6 m x 4.6 m double array of plastic scintillation counters vetoed charged particles entering from upstream of the decay channel The channel itself measured 34 m in length and was interspersed with m x m argon-ethane drift chambers positioned at 14.5 m, 24 m, and 34 m downstream of the veto array in stations of 1, 1, and chambers, respectively The regions between the drift chamber stations were occupied by helium-filled cylindrical plastic bags 4.6 m in diameter In the off-line analysis, tracks were reconstructed from drift chamber hits and grouped together to form vertices The tracking algorithm took into account multiple Coulomb scattering, using a full error matrix for the fit Sets of tracks were grouped as candidates for a vertex if their distance of closest approach was less than 12.7 cm The vertex position was then determined using a constrained fit Typically, a vertex from a NO of mass GeV/ c2 would be reconstructed with a resolution of 0.13 cm in the transverse direction and 7.4 cm longitudinally The Lab E neutrino detector [9,10], located immediately downstream of the decay channel, provided final state particle energy measurement and identification This detector consisted of a 690 ton iron-scintillator target calorimeter followed by a toroidal muon spectrometer Three-wire argon-ethane drift chambers were positioned every 20 cm along the length of the calorimeter, and 84 2.5 cm-thick liquid scintillator counters were interleaved with the steel plates at 10 cm intervals throughout its length The spectrometer had a 15 kG toroidal magnetic field with drift chambers interspersed throughout the toroid magnets to provide tracking for the muons III PHILOSOPHY OF THIS ANALYSIS In analyses such as this, there is a real concern that events may be eliminated or isolated through an unintentional bias of the people involved in the analysis The solution adopted by many collaborations is that of a "closed box" analysis, in which there is no direct access to the signal region until the end of the analysis This procedure was a philosophical goal of this search However, before this analysis, during the early development of the reconstruction 581 software for the decay channel, one candidate decay channel event with two muon tracks was observed This event was studied in detail and ascertained to have a mass greater than 2.2 GeVjc2 Because of the observation of this event, the NuTeV collaboration went to considerable effort to minimize bias Investigations of data events with high mass were stopped until the MC background studies (described below) were completed to establish the cuts and requirements In most cases, cuts set prior to the observation were used In those cases where new cuts were introduced, demonstration of a strong MC-based motivation was required New members who had not seen the event joined the analysis group Finally, an important aspect of the analysis included setting up orthogonal analysis regions and comparing Monte Carlo prediction to the result Each of the two previously-published analyses was motivated by its own physics goals, but they also represent tests in regions complementary to this analysis As part of the analysis philosophy, once the analysis region was selected based on the Monte Carlo criteria, the collaboration agreed to show any events which were observed However, the interpretation of the events might change after the analysis rl?gion was examined, upon further investigation IV EVENT SELECTION Event selection criteria were developed to minimize known backgrounds while maintaining efficiency for a possible NO signal 585 (x or y) with fewer than eight drift chamber hits total in the first two chambers downstream of the vertex, 4) no energy clusters in the calorimeter not associated with tracks, and 5) no tracks identified as electrons with missing hits in either view of the first two chambers downstream of the vertex Requirements 1-3 remove events with high multiplicities; requirement removes events where a neutral particle deposits energy in the calorimeter; and requirement was used to reduce events with photon conversions in the downstream chambers which could be misidentified as electrons TABLE II Identification of events with exiting tracks, neutral particles, and photon conversions; these characterize DIS events and are removed by the "clean" cuts Extra tracks >3 tracks in either view Exiting tracks > extra hit in either view in the chamber just downstream of vertex or > hits in each view in the first chambers downstream of the vertex Neutral particles ~ cluster(s) in calorimeter without associated track Photon conversion Electron PID with no hits in chamber immediately downstream of vertex V BACKGROUND ESTIMATION USING MONTE CARLO Detailed Monte Carlo simulations of both physics processes and detector effects were used to quantify the background from neutrino interactions after cuts Input to the simulation was provided from several event generators The LEPTO/Jetset Monte Carlo program was used to simulate DIS events [11] This simulation used CCFR parton distributions [12], included the correct A-dependence [13], and generated DIS events from Q2 > 0.1 Gey2 and W > GeY Resonance and continuum production, simulated using the calculations of Belusevic and Rein [14], allowed us to extend the Monte Carlo into the low-W region Diffractive production was calculated using Vector Meson Dominance (YMD) and Partially- 586 Conserved Axial Current (PCAC) models normalized to a previous measurement with the NuTeV calorimeter data [15] The event generators fed a GEANT-based [16] detector simulation that produced hitlevel simulations of raw data Cell-by-cell inefficiencies and dead regions due to internal chamber supports were included To simulate noise and accidental activity in the detector, decay channel hits taken from in-time downstream calorimeter neutrino events were overlaid on the GEANT events Monte Carlo events were processed using the same analysis routines used for the data Background calculations were normalized to the data using charged-current DIS interactions in the chambers The Monte Carlo was normalized to match the total number of data events with two or more tracks Figure shows a comparison of the data and MC distributions for this sample The preliminary error on this normalization is 9% Two alternate normalizations were used as checks These alternative cross-checks had uncertainties of 16% and 12% respectively, and were in agreement with the primary normalization Monte Carlo events were compared to data as a check on the quality of the simulation In such a comparison, the challenge is to isolate events of sufficiently similar topology to 587 verify the Monte Carlo calculation of the background and at the same time maintain high statistics in the data sample We have employed a number of different methods to achieve high statistics comparison samples of events with two or more tracks In one particular study, we required that the vertex be within the decay channel fiducial volume, with Ixl < 127 em, Iyl < 127 em, allowing the z position to be either in the chambers or the helium Tight track angle cuts were imposed to remove cosmic rays, and a strict requirement on veto system activity was used to remove upstream interactions Other cuts on reconstruction, particle identification, and vertex fit quality were removed The majority of these events were from interactions in the chamber material or from interactions in the laboratory floor In the data, from 502 events, 169 events had vertices reconstructed in the helium, defined as > 101.6 em for the nearest drift chamber This can be compared to Monte Carlo, which predicted (525 ± 84) events with (159 ± 25) events reconstructed in the helium Comparisons of data to Monte Carlo vertex distributions are shown in Figures and FIG Longitudinal vertex position for all events in the decay channel fiducial volume (Crosses: data; histogram: Monte Carlo) Peaks correspond to interactions in veto wall and test beam chamber (left) and drift chambers DK5 and DK4 (center and right) 589 VI CROSS-CHECKS USING DATA Before looking at the data in the signal region, we performed a series of analyses on other fiducial and kinematic ranges which gave us confidence in our Monte Carlo predictions We point out that the two previous published analyses in the 0.3 to 3.0 GeV /2 and low mass region were examinations of other such kinematic regimes Extra studies performed for this analysis included using 1) identical analysis cuts applied to events within ±15.2 cm of a chamber (the chamber region); 2) the chamber region with loosened cuts to increase p:rr acceptance; 3) the "intermediate region" between 15.2 and 101.6 cm from the chambers, with otherwise standard analysis cuts; and 4) events with well-reconstructed two-track vertices where the tracks were both identified as pions The results were within 1.5a of prediction in the above cases VII RESULTS OF THE SEARCH FIG Kinematic distributions (transverse mass, invariant mass and missing transverse momentum) for the 5.0 GeV Ie? NO Monte Carlo The histograms show the MC; the arrows indicate the three observed events ... BASICS AND HIGHLIGHTS IN FUNDAMENTAL PHYSICS THEORY AND EXPERIMENT HEADING FOR NEW PHYSICS Volume I was published by W A Benjamin, Inc., New York; 2-8 and 11-12 by Academic Press, New York and London;... Press, New York and London; 30-38 by World Scientific, Singapore 1he Subnuclear Series • Volume 38 Proceedings of the International School of Subnuclear Physics THEORY AND EXPERIMENT HEADING FOR NEW. .. International School of Subnuclear Physics (38th: 2000 : Brice, Italy) Theory and experiment heading for new physics: proceedings of the International School of Subnuclear Physics I edited by Antonino