Elementary Particle Physics

Transcription

1 Research Field Structure of Matter Helmholtz Research Programme Elementary Particle Physics Participating Centres: Deutsches Elektronen-Synchrotron, DESY Forschungszentrum Karlsruhe, FZK Programme Spokesperson: Research Field Coordinator: Prof. Dr. R. Klanner, DESY Prof. Dr. A. Wagner, DESY

2 Helmholtz Association Mission Statement The fifteen national research centres joined together in the Helmholtz Association pursue longterm research goals on behalf of government and society, including basic research performed in scientific autonomy. The Association identifies and addresses grand challenges facing society, science and industry by carrying out top-rate research in strategic programmes in the fields of Energy, Earth and Environment, Health, Key Technologies, Structure of Matter, Transport and Space. In particular, the Helmholtz Association researches systems of great complexity. Its activities are organised in longer-term programmes. International peer reviews of these competing programmes form the basis of federal and state government funding for the activities of the Association. The Association meets the grand challenges by bringing together the knowledge and resources of various disciplines and centres as well as by cooperating and networking with key national and international partners in science, especially from universities, and industry. The Helmholtz Association is especially responsible for planning and operating large-scale facilities and scientific infrastructure. These form the focal point of national and international collaborative research projects, drive forward high-tech development, and raise the international appeal of Germany as a centre for science and research. Scientists at the Helmholtz Association help to shape our future by combining research and technological development with innovative applied and forward-planning perspectives. The special competences, creativity and motivation of the staff are essential to the Helmholtz Association Mission. The Association attaches great importance to maintaining and enhancing these key qualities. This is why the Association offers its staff opportunities for personal and professional development as well as excellent working conditions in an exceptional environment and promotes equal opportunity. The Helmholtz Association supports young scientists, contributes to their professional qualification by providing training in its research fields, and additionally offers the chance for early scientific independence. Moreover, the Helmholtz Centres also train highly qualified technical personnel. The Helmholtz Association supports the dialogue between science and society by communicating research topics and findings and taking up impulses from the public sphere. It helps politics and society gain a better understanding and assessment of the consequences of human activity and so supports decision-making on an informed basis. The concerted use of its resources enables the Helmholtz Association to contribute importantly to advancing scientific progress, to shaping our future and to protecting the foundations of human life.

3 Research Field Structure of Matter Helmholtz Research Programme Elementary Particle Physics Participating Centres: Deutsches Elektronen-Synchrotron, DESY Forschungszentrum Karlsruhe, FZK Programme Spokesperson: Research Field Coordinator: Prof. Dr. R. Klanner, DESY Prof. Dr. A. Wagner, DESY

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5 Research Field Structure of Matter of the Helmholtz Association Table of contents: 1 RESEARCH FIELD STRUCTURE OF MATTER OF THE HELMHOLTZ ASSOCIATION - EXPLORING NATURE IN ITS FUNDAMENTAL PROPERTIES THE SCIENTIFIC GOALS THE OVERALL STRATEGY AND FUTURE PERSPECTIVES POLITICAL DECISIONS WITH LONG RANGE IMPACT THE PROGRAMMES AND THEIR STRATEGIC IMPORTANCE THE SCIENTIFIC AND TECHNICAL ASSETS PARTICIPATION OF CENTRES IN THE RESEARCH FIELD ELEMENTARY PARTICLE PHYSICS DEFINITION OF THE FIELD AND STRATEGIC RELEVANCE OF THE PROGRAMME CHALLENGES AND OPPORTUNITIES PROGRAMME OVERVIEW INTEGRATIVE ASPECTS DETAILED PROGRAMME FOR THE PERIOD Programme topic: HERA II physics and collider (DESY) Programme topic: Beyond HERA II: e + e - physics, LC and external experiment (DESY) Programme topic: Computing for Particle Physics (DESY, FZK) Programme topic: Theoretical Particle Physics (DESY) RESUME / VISIONS FOR THE LONG-TERM FUTURE ANNEX COMPETENCE OF PARTICIPATING CENTRE PROGRAMME ELEMENTARY PARTICLE PHYSICS COMPETENCE OF PARTICIPATING CENTRE DESY Science related information Infrastructure Third party funding Innovation data Promotion of young scientists / promotion of women Networking details Information on large-scale facilities Outreach COMPETENCE OF PARTICIPATING CENTRE FORSCHUNGSZENTRUM KARLSRUHE (FZK) Science related information Infrastructure Third party funding Innovation data Promotion of young scientists / promotion of women Networking details Information on large-scale facilities Outreach RESOURCE PLANNING DESY FZK

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7 Research Field Structure of Matter of the Helmholtz Association 1 Research Field Structure of Matter of the Helmholtz Association - Exploring Nature in its Fundamental Properties Coordinator: Prof. Dr. Albrecht Wagner (DESY) Participating Research Centres DESY, Deutsches Elektronen-Synchrotron, Hamburg GKSS, Forschungszentrum, Geesthacht GSI, FZJ, FZK, HMI, Gesellschaft für Schwerionenforschung, Darmstadt Forschungszentrum Jülich Forschungszentrum Karlsruhe Hahn-Meitner-Institut, Berlin 1.1 The Scientific Goals Exploring the Structure of Matter is to unravel the fundamental properties of the world, ranging from the very small to the very large; to understand the structure and dynamics of matter we are made of and which we find around us at very different and increasing levels of complexity. The scientific goals of the research field Structure of Matter range from the search for the elementary building blocks, the fundamental forces and the symmetries that govern the interactions between these, to the basic properties and relevant degrees of freedom that determine the physical behaviour of matter. This research deals with the three ''infinities'', elementary constituents of matter on the very small scales, distant structures of the universe on the very large scales, and the complex phenomena caused by the interplay of the myriads of atoms of a solid or a liquid in condensed matter. The research field is organized in five programmes: 1. Elementary Particle Physics studies the basic building blocks of matter and the forces acting between them, and searches for new forms of matter and for the laws governing the evolution of the early universe. 2. Astroparticle Physics represents research at the intersection of astronomy, astrophysics, cosmology and Particle Physics. It combines the knowledge about the fundamental particles and the largest structures in the universe. 3. The Physics of Hadrons and Nuclei aims at a quantitative understanding of all matter made of quarks, ranging from the question why quarks are confined in hadrons to the limits to the existence of atomic nuclei, the origin of chemical elements, and the properties of extended nuclear matter objects in the universe such as neutron stars. 4. Condensed Matter Physics provides the basic understanding of the complex properties of matter and materials which are relevant, e.g. to life sciences, chemistry, information technology and engineering

8 Research Field Structure of Matter of the Helmholtz Association 5. The programme Large Scale Facilities for Research with Photons, Neutrons and Ions focuses on the design, development, construction and operation of major facilities for structural research in a broad range of fields of science. 1.2 The Overall Strategy and Future Perspectives The overall strategy of the research field is to further strengthen the position of Germany on a world level as a key player in the discovery of the fundamental properties of the world and in the understanding of the structure and dynamics of matter. Most of the scientific programmes are strongly related to existing and planned facilities. The Helmholtz centres active in the research field Structure of Matter carry the main responsibility for developing, building, and operating the large research facilities in Germany, e.g. particle and ion beam accelerators, synchrotron light sources and neutron sources as well as large scale spectrometer facilities. Through their infrastructure, they serve national and international scientists from many fields with unique research tools. To maintain leadership in their fields of research they pursue at the same time their own research. As stated by the German Science Council in its evaluation of the Helmholtz Association, the operation of large facilities is a core strength of the Helmholtz centres which contributes strongly to the internationalisation of German science and makes Germany an attractive research location. The reason for the international use of the facilities is that some of them are unique on a world-wide scale. The facilities are worked out in close cooperation with the national and international science communities. It is a central goal of the present and future programmes to keep up and strengthen this specific core competence. The programmes based on large-scale research facilities have as common goals the solution of key scientific questions, the efficient operation of the existing research facilities, the support for the national and international users, and maintaining leadership by developing and building new facilities in international co-operation. Therefore the strategy for the future encompasses four parts: to fully exploit the existing facilities, to build and operate advanced new facilities, to perform basic research in the five programmes of the research field, and to strengthen the internal and external co-operation across the borders of specific research areas. Based on the knowledge gained in the past, researchers in the Helmholtz centres have defined their future programmes. A major part of these are new powerful facilities which would enhance the strength of the Helmholtz Association: Elementary Particle Physics: Particle physicists have formed a world-wide consensus to build jointly an electron-positron linear collider as their next major facility, as it would provide unique new insight into fundamental particles and forces, possibly new constituents of matter, and the physics laws governing the early universe. DESY, together with partners in 12 countries, has developed the TESLA project

9 Research Field Structure of Matter of the Helmholtz Association FZK together with CERN, DESY and the international Particle Physics community is developing the infrastructure and tools for a world-wide Grid-computing for the LHC and other experiments. Astroparticle Physics: The international projects AUGER, KATRIN (with contributions from FZK) and ICECUBE (with contributions from DESY) are future large facilities for cosmic ray and neutrino astrophysics, building upon the successful existing research programme. Physics of Hadrons and Nuclei: GSI together with the European community in nuclear and hadron physics, is developing a new facility for intense beams of ions and antiprotons to answer the question of how the fundamental building blocks of matter and forces lead to the creation of the complex structures of matter that constitute our universe today. For spin-physics experiments, the FZJ proposes to increase the intensity of polarized beams up to the space charge limit. Condensed Matter: The exploration of the dynamic processes of structure formation and self-organisation in condensed matter and in novel phases of complex materials is advanced by an integrated approach on multiple scales from sub-atomic to macroscopic. This also guarantees a strong impact in many fields of science and engineering, across disciplinary boundaries. Condensed matter research will continue to generate ideas for the new tools and complementary techniques of investigation, including in particular novel instrumentation at large scale facilities. Research with Photons, Neutrons and Ions: A European Free-Electron X-Ray Laser Laboratory as an outstanding new tool for studying the structure and dynamics of matter with photons is pursued by DESY. PETRA III will be operated as a third generation storage ring synchrotron radiation facility at DESY. FZJ will open the gateway for German users to the then world's most powerful pulsed megawatt spallation neutron source SNS at Oak Ridge/ US. For this purpose, novel instrumentation at SNS will be designed and commissioned by FZJ in collaboration with HMI. A VUV FEL user facility at DESY and a high power (petawatt) laser at the GSI are currently under construction

10 Research Field Structure of Matter of the Helmholtz Association Some of these proposals have been reviewed by the German Science Council which emphasised that i) the initiation or development of totally new areas of research is closely related to the availability of specific new facilities, ii) large-scale facilities should stem from a broad initiative of scientific users with equal rights and that iii) large-scale facilities must be based on long-term scientific visions, and the prerequisites for technical innovations must be given. 1.3 Political Decisions with Long Range Impact In February 2003 the Federal Ministry for Education and Research (BMBF) took decisions of outstanding importance for the research field Structure of Matter : A new X-ray Free Electron Laser is to be built at DESY as a European project. Germany offers to cover half of the investment cost. In addition DESY will receive funds to transform the existing storage ring PETRA into a third generation synchrotron radiation facility. GSI, together with European partners, will construct, in a phased approach, a major new facility for beams of ions and antiprotons, with the current accelerator system as injector. Thereby, GSI will become the leading European centre for the field of hadron and nuclear physics with hadron beams. At least 25% of the total cost is to be provided by foreign partners. No German site is at present proposed for the TESLA linear accelerator. DESY, however, is recommended to continue its international research work so that a German participation in a future global project will be possible. These decisions enable the Helmholtz centres to continue to provide the facilities, the technical knowhow, and the scientific strengths to play an international leadership role in the research field Structure of Matter. They make Germany also in future attractive for scientists from all over the world and provide the basis for strong research partnerships on a European and international level, in excellent agreement with the mission of the Helmholtz Association. 1.4 The Programmes and their Strategic Importance The five programmes are focusing on key questions in their respective fields and the tools necessary to answer them. Some of the programmes are interconnected, both scientifically and technologically. All programmes are based on a close interplay between experiment and theory. 1. Elementary Particle Physics (DESY, FZK) Elementary Particle Physics studies the basic building blocks of matter and the forces acting between them, and searches for new forms of matter and for the laws governing the evolution of the early universe. The central part of the programme exploits the unique electron-proton collider HERA at DESY to study the inner structure of the proton and the specific properties of the strong, electromagnetic and weak forces. In addition sensitive searches for new particles are performed - 6 -

11 Research Field Structure of Matter of the Helmholtz Association which extend beyond the current fundamental theory of Particle Physics. The operation of HERA is planned to end in DESY has been developing for the last 10 years, within the international TESLA collaboration, the accelerator technology for a TeV electron-positron collider. Fundamentally new phenomena are expected in this energy range, beyond the reach of present accelerators. In parallel, a protonproton collider (Large Hadron Collider, LHC) is under construction at CERN. Complementary to it, the electron-positron collider TESLA will help answer the following key questions: The origin of mass, the unification of all fundamental forces at very high energies, the search for a new kind of matter (super symmetric partners of all known particles), and the unification of quantum physics and general relativity. The accelerator based programme is supplemented by the development of a world-wide Gridcomputing initiative which will serve the LHC data analysis and other Particle Physics experiments (FZK together with CERN and DESY). DESY together with European partners is developing a 10TFlop computer for particle and nuclear physics. 2. Astroparticle Physics (FZK, DESY) Astroparticle physics represents research at the intersection of astronomy, astrophysics, cosmology and Particle Physics. This new interdisciplinary field has become a focus of great activity in recent years. It combines our knowledge about the smallest fundamental particles and the largest structures in the Universe. Astroparticle physics explores the sources of ultra-high energy cosmic rays and the mechanism of cosmic accelerators, and studies the Universe beyond classical multiwavelength observations, using gamma rays, neutrinos and cosmic rays at all energies. Astroparticle physics uses the cosmological accelerators and large infrastructure installations such as huge detector arrays, frequently applying technologies developed in the field of Particle Physics. The programme consists of three main parts: i) Studies of the nature, origin and propagation of cosmic rays at high and ultra-high energies with air shower detectors (KASKADE Grande Experiment, AUGER Observatory); ii) The search for high-energy neutrinos from astrophysical sources with neutrino telescopes (AMANDA, Icecube). iii) The determination of the electron neutrino mass with a precision of relevance for Particle Physics and cosmology (KATRIN). 3. Physics of Hadrons and Nuclei (GSI, FZJ, FZK) The goal of the physics of hadrons and nuclei is a comprehensive and quantitative understanding of all matter that is made of quarks and that is governed by the strong and to some extent also by the electro-weak force. This general goal translates into a number of major themes: The study of confinement of quarks in hadrons, the understanding of the mechanism of spontaneous chiral symmetry breaking, the origin of the mass of hadrons, the properties of the nuclear many-body system, the reach for the most of exotic nuclei at the limits of stability, the behaviour of extended - 7 -

12 Research Field Structure of Matter of the Helmholtz Association nuclear matter in astrophysical objects and processes such as neutron stars and supernovae, the general phase transitions from hadronic to quark matter, and the search for new forms of matter. The programme centres around the following major facilities: Research at the high-current heavy ion-linear accelerator (UNILAC), the high-energy heavy-ion synchrotron (SIS) and the experimental storage ring (ESR) at GSI, as well as at the cooler synchrotron (COSY) at FZJ, with beams of unpolarised and polarised protons and deuterons. In the field of hadron and nuclear reaction physics at very high energies, Helmholtz centres significantly contribute to the research programmes carried out at the CERN SPS and those planned for the LHC. To maintain the leading position of the Helmholtz Centres and its user community in the field of hadron, nuclear and general ion-beam physics, GSI, together with universities and institutes from Germany and abroad, develops an International Accelerator Facility for Research with Heavy Ions and Antiprotons. The new facility should be operational around Condensed Matter (FZJ, FZK) Research in the field of Condensed Matter is concerned with the wealth of effects caused by the interplay of a very large number of atoms of a solid or a liquid. The interaction and cooperation of electrons, atoms and molecules within a many-body system is responsible for the different properties of materials and why they are solid, fluid or gaseous, soft or hard, transparent or opaque, magnetic, metallic or even superconducting. Extremely wide length and time scales, often interdependent on each other, are characteristics of the complexity of condensed matter, ranging from subatomic sizes up to macroscopic measures, and from electronic relaxation times of femtoseconds up to geological periods. The investigations require powerful instrumentation. Condensed matter physics is here in close interaction with the neighbouring disciplines of chemistry and biology as well as the geo-sciences and medicine, and affects wide fields of the engineering sciences. Information technology as an example simply would not exist without condensed matter physics. The strategy of the programme focuses on exploring new and unique processes in three areas of Condensed Matter: Electronic and Magnetic Phenomena, From Matter to Materials, and Soft Matter and Biophysics. The programme is based partly on the use of large facilities for neutron and synchrotron radiation, and is complemented by other techniques such as in-house high resolution spectroscopy, thermodynamic and transport measurements, high-resolution electron microscopy as well as theory and computer simulation. 5. Large Scale Facilities for Research with Photons, Neutrons and Ions (DESY, FZJ, FZK, GKSS, GSI, HMI) Electron ring accelerators are powerful sources of synchrotron radiation. This radiation, especially in the X-ray domain, is a major tool in many fields of science, as it penetrates matter and reveals its inner structure. Similar to synchrotron radiation, neutrons are playing an outstanding role in the - 8 -

13 Research Field Structure of Matter of the Helmholtz Association analysis of structural and dynamical properties of condensed matter and materials. Also ion beams serve to analyse and modify matter and its properties. The large scale facilities grouped in this programme are of crucial importance for atomic, molecular, plasma and condensed matter physics, for structural molecular biology and chemistry, for material, geo- and environmental sciences, as well as for engineering and other applications. The central part of the programme is based on the operation and exploitation of the existing light, neutron and ion sources for many scientific questions. In addition two new facilities will become operative in the near future: A VUV FEL user facility at DESY (2004) and a high power (petawatt) laser at the GSI (2004). DESY continues the development of a European Free Electron Laser Laboratory for hard X-rays based on TESLA technology. In the midterm (2006), FZJ will take the lead to open the way for the German users to the new megawatt spallation source (SNS) at Oak Ridge/USA through participation - jointly with HMI - in the development of its instrument suite. This will allow German scientists to stay at the frontier of neutron science. 1.5 The Scientific and Technical Assets The large scale facilities in Germany are a core responsibility of the Helmholtz centres united in this research field. All facilities are quite unique in their performance and user profile. They have been built and are continuously being upgraded in close interaction with and for national and international users from universities and industry. The Helmholtz centres are therefore at the same time centres of excellence in science and technology and service providers, supporting scientists from universities and other research institutes to make best use of the facilities. The Helmholtz scientists play a key role in leading new initiatives in their field of research, in using the facilities for their own research, in providing high-level scientific and technical infrastructure support for user experiments, in developing novel technologies and instrumentations, in the training of young researchers together with universities and other research institutes, and in attracting scientists from around the world to Germany. One goal of Helmholtz programme-oriented funding scheme is to further strengthen the coordination and networking between centres. It is a particular feature of the research field Structure of Matter that the large research infrastructures provide the backbone for a network, both between the different Helmholtz centres and especially between the national and international user communities. It has been the strategy of the centres in the past to be as complementary with respect to each other as possible while being strongly coupled to the users and their needs for the development of the facilities and for their optimal use. Progress in the understanding of the micro- and macro-cosmos is driven by the curiosity to answer fundamental questions, with no a-priory application in mind but with major spin-offs along the way. Novel forms of condensed matter are likewise the subject of basic research, yet with a strong link to - 9 -

14 Research Field Structure of Matter of the Helmholtz Association possible applications. This research is linked to a large extent by the need for and dependence on large research tools and their continuous development. There is also a close relation in model development and analysis. The research into structure of matter and the development in accelerator technology have led to breakthroughs in technology, to new methods and instrumentation with other applications in science and elsewhere, ranging from tumour therapy to the production of radioactive substances for medical diagnostics, and to the possibilities to build X-ray lasers and spallation neutron sources. 1.6 Participation of Centres in the Research Field Direct R&D costs* in T DESY FZJ FZK GKSS GSI HMI Elementary Particle Physics Astroparticle Physics Physics of Hadrons and Nuclei Condensed Matter Research with Photons, Neutrons and Ions * including third party funding F&E personnel in FTE** DESY FZJ FZK GKSS GSI HMI Elementary Particle Physics Astroparticle Physics Physics of Hadrons and Nuclei Condensed Matter Research with Photons, Neutrons and Ions ** Full Time Equivalent (person-years) Table: Direct R&D costs and personnel for the research field Structure of Matter at the programme level in

15 2 Elementary Particle Physics 2.1 Definition of the field and strategic relevance of the programme The aim of Elementary Particle Physics is to reveal, and develop an understanding of, the fundamental structures and laws of the micro-cosmos and from these to produce a consistent description of nature for distance scales from m, the size of the presently visible universe, down to m, where the known forces of nature are expected to be unified; and for time scales from years, the age of the universe, down to sec, the scale which characterises its beginning. Status and main aims At the beginning of the 21 st century, Particle Physics has revealed that matter consists of three families of leptons and quarks which interact via the weak, electromagnetic and strong forces. These are described within the Standard Model by quantum field theories which obey a symmetry principle, gauge invariance. In the Standard Model, the Higgs mechanism, which has yet to be tested by experiment, is responsible for the masses of the fundamental building blocks of matter, the quarks and the leptons, and for the masses of the particles carrying the forces. The Standard Model has been verified by precision measurements and has demonstrated its power by correctly predicting, e.g. the masses of the W and Z bosons, and of the top quark. In particular the electro-weak sector of the Standard Model has been and is being tested with great precision in past and present experiments. That part of the Standard Model that describes the strong interaction, QCD, has been shown to describe very well data on interactions at distances well below the size of the nucleon. For larger distances, where the equations of QCD have yet to be solved, progress is being achieved through experimental developments, e.g. at HERA, and theoretical advances, notably Lattice Gauge Theory and phenomenological models. In spite of its successes, the Standard Model leaves open fundamental questions about Elementary Particles, the forces between them and the symmetries to which they subject. Gravity, for example, the dominant force in the universe over large distances does not feature at all within the Standard Model. However, the currently available precision data and the predictive power of the Standard Model suggest strongly that with the present and the next generation of high-energy particle accelerators, the Large Hadron Collider (LHC) and a high-energy electron-positron linear collider (LC), the following fundamental questions can be answered: What is the origin of the mass of the Elementary Particles? Do the known forces have a common origin? Is supersymmetry realised in nature? What is the structure of space and time? Are there more than three spatial dimensions? Links to other fields Particle Physics is closely linked with many other fields of science. The questions posed today in Particle Physics have a direct bearing on fields like Cosmology and Astroparticle Physics, just as discoveries in these fields influence developments in Particle Physics. Cosmological challenges for Particle Physics include the description of the earliest stages in the development of the universe and of dark matter. On the other hand, observations made in Cosmology constrain strongly the properties of particles, the mass of the neutrinos, for example. Astroparticle Physics, which studies the particles from cosmological accelerators, is closely linked to Particle Physics, both in terms of the questions studied and the experimental methods used. There is also a strong overlap with the research field Hadrons and Nuclei, which studies the properties of the strong and weak forces at low energies. Examples include the study of the structure of the nucleon and of the nature of parton radiation and the quest for

16 an explanation of quark confinement. Strong links exist as well to the field of computer science, both on a theoretical level and as regards practical applications. Strategic relevance Attempts to understand nature at its most fundamental level and to unravel the origin of the universe have long been a central part of human endeavour and have attracted some of mankind s brightest minds. This continues to be the case; not only does High Energy Physics attract some of the best students, it fascinates a broad public. The Standard Model of Particle Physics is an intellectual achievement of importance similar to Quantum Mechanics in the first part of the 20 th century. Understanding its foundations is one of the big scientific challenges at the beginning of the 21 st century. The tools and methods developed and used by theoretical and experimental particle physicists, such as accelerators, complex detectors, novel data analysis methods, high performance computing and information technology, render Particle Physics a motor of innovation. Many of today s technologies trace their origin to Nuclear or Particle Physics experiments. Examples include: accelerators and particle detectors for medicine; synchrotron radiation and neutron and ion beam sources for materials research and structural biology; communication via and the World Wide Web and the remote computer controlled operation of complex systems. Superconducting accelerators, the X-ray Free Electron Laser and grid computing are all examples of ongoing developments within Particle Physics which will have a significant impact outside the field. Last but not least, the wide spectrum of complex questions, the development of cutting-edge technologies and the need for global collaboration mean that Particle Physics provides an exceptionally broad education for young scientists, many of whom then move into careers in the private sector, academia or government services. 2.2 Challenges and opportunities The period will be a time of unique opportunities for High Energy Physics. The recent demonstration that the mass of the neutrino is finite has presented new experimental and theoretical challenges. The ongoing programmes at the energy frontier, at HERA and at the Tevatron, will be concluded and will prepare the ground for the LHC and the LC. The LHC, which will start operation in 2007, will be the first accelerator to reach beyond the electro-weak energy scale. Work towards the LC, the project agreed by the worldwide Particle Physics community to be the highest priority big new project in the field, will progress. The Helmholtz centres, Deutsches Elektronen-Synchrotron, DESY, and Forschungszentrum Karlsruhe, FZK, will contribute to these exciting developments with their programmes: DESY will operate HERA until 2006/2007 with high luminosity and polarised electron/positron beams. Based on these data the HERA experiments will gain new insight into many aspects of the strong and electro-weak forces and expand the searches for new physics into presently unknown territory. DESY is strongly committed to the linear collider as its next project in Particle Physics and will contribute to the accelerator, to physics studies and to detector development. In the period the linear collider project will meet a number of important milestones, both at DESY and internationally

17 Together with its partners from universities and Particle Physics laboratories from around the world, DESY will contribute towards the development of a novel collaborative organisation, the Global Accelerator Network (GAN), which will develop and run the next generation of accelerators. DESY will maintain an attractive and first-rate Particle Physics programme during the transition period from HERA to the linear collider. Participation of DESY at external experiments to ensure this is under review. DESY will maintain its strong role in Theoretical Particle Physics, including the development and operation of computing resources for Lattice Gauge Theory. FZK will continue to build and operate the Grid Computing Centre Karlsruhe, GridKa, as a German user facility for the analysis of high rate experiments in Particle Physics using technologies and organisational structures developed in the context of the LHC Computing Grid (LCG). Particle Physics in Germany can look back onto a highly successful past. German physicists have participated in all major High Energy Physics experiments at laboratories throughout the world, with the focus of their activities at CERN in Geneva and at DESY in Hamburg. DESY has built and operated the synchrotron DESY, the storage rings DORIS and PETRA and most recently HERA, the world s only electron-proton collider. These accelerators have led to significant advances in our understanding of Particle Physics and to the high international standing that DESY enjoys. The TESLA collaboration, hosted by DESY, has been and will continue to be a driving force in the development of the technology for a superconducting high energy linear collider. DESY in close collaboration with university groups and research institutes from around the world has advanced the physics case for a linear collider and is studying the design of a detector for such a machine. German physicists are deeply involved in shaping the experimental High Energy Physics programme for the next 20 years. The Helmholtz centres, together with their partners from the German universities and Max-Planck institutes and in close collaboration with their international counterparts, are committed to continue in this tradition of excellence. 2.3 Programme overview Overview of strategy The Helmholtz centres which participate in the Research Programme Elementary Particle Physics are DESY, located in Hamburg and Zeuthen, and FZK in Karlsruhe. DESY is one of the world s few large accelerator centres and has a long history of developing and running accelerators (DESY) and storage rings (DORIS, PETRA, HERA) for the German and international Particle Physics communities as well as for research with synchrotron radiation. International collaborations involving as many as 50 institutions including DESY, developed, designed and built the complex Particle Physics experiments which they jointly operate to exploit the DESY accelerators. A strong theory group is an essential and integral part of DESY s Particle Physics activity

18 Figure: Personnel for the programme in 2003 excluding third party funded persons. The strategy for the programme Elementary Particle Physics is based on worldwide discussions and a consensus on the scientific and strategic goals of Particle Physics for the next twenty years, the expertise and missions of the participating Helmholtz centres and the Forschungspolitische Vorgaben of the German government. Its aim is to strongly support German research groups in Particle Physics and to enable the Helmholtz centres to play a unique and prominent role in Particle Physics on a worldwide scale. The strategy has been discussed within the German and international Particle Physics communities and the laboratories and by the corresponding advisory bodies. FZK, through the Grid Computing Centre Karlsruhe, GridKa, recently became the German centre for the analysis of the data from present and future large-scale Particle Physics experiments. These are in particular the LHC experiments ALICE, ATLAS, CMS and LHCb, which are scheduled to start data taking in 2007, and the running experiments BaBar, CDF, D0 and COMPASS. Theory The DESY theory group, in close collaboration with local university groups, pursues a vigorous and broad research programme in Theoretical Particle Physics. The group has achieved worldwide recognition and is considered one of the leaders in the field. The group Elementary Particle Physics of the John-von-Neumann Institute for Computing (NIC) at Zeuthen, together with local universities and members of the DESY theory group, is one of the leading centres for Lattice Gauge Theory. Together with the NIC, DESY develops and provides high-performance computing on massively parallel computers to the German Lattice Theory community. The research topics that are addressed by the DESY theory group cover general phenomenology and perturbative Quantum Field Theory, supersymmetry, neutrinos, grand unification and Cosmology, string theory, and Lattice Gauge Theory. Due to the quality of its research, the close collaboration with experimentalists and with German and international theory groups, its post-doc and guest programme, and the organisation of conferences, workshops and schools, the DESY theory group has a significant impact on Particle Physics. It also fulfils a major service for the German Particle Physics community through the education of theoretical physicists in Germany. DESY is committed to the continuation of this very successful tradition. HERA The electron (positron)-proton collider HERA, with its centre-of-mass energy of 320 GeV, is a unique research facility worldwide. Its construction, with major foreign contributions in both manpower and components within the so-called HERA-model, was a milestone in the field. Colliding particles with properties as different as those of electrons and protons is a particular challenge and the success of HERA in this respect is a tribute to the DESY accelerator group. Approximately 1200 experimental

19 physicists from all over the world have built and are running four large detectors (H1, ZEUS, HER- MES and HERA-B) to exploit the physics opportunities offered by HERA. A large theoretical community profits from the HERA results which have particularly advanced the understanding of the strong interaction. In the first phase (HERA I: ) the experiments made two major discoveries: the strong increase of the parton density in the proton at high energies and the observation that in ~10% of deepinelastic ep events the proton remains intact. In addition, HERA I provided new insight into many aspects of the strong interaction. The precise measurements of the scale dependence of the strong coupling constant and the demonstration of electro-weak unification in deep-inelastic scattering are results which have already made it into the textbooks. Searches for physics beyond the Standard Model at HERA I have provided several stringent limits and a number of interesting events. The larger data samples that will be obtained at HERA II will reveal whether these are the first signatures of new physics processes or whether they can be understood within the Standard Model. In , HERA was upgraded to produce higher collision rates (luminosity) and polarised electrons/positrons at the H1 and ZEUS interaction regions. The H1 and ZEUS detectors were simultaneously upgraded to allow them to cope with the increased collision rates and to provide improved detector performance. HERA thus entered its second phase, HERA II. The HERA II programme is expected to last until 2006/2007 when the main physics goals of the upgrade are likely to have been reached. The end date of HERA II is dictated by the transformation of one of the HERA injectors, PETRA, into a dedicated synchrotron radiation source. The main aims of the HERA II programme are: For each of H1 and ZEUS to obtain close to 1 fb -1 of ~50% polarised positron/electronproton data to enable precision tests of QCD, to test electro-weak theory, to measure electroweak parameters and to search with high sensitivity for physics beyond the Standard Model, For HERMES to obtain 150 pb -1 of data with ~50% polarised positrons/electrons on a transversely polarised proton target to allow a first measurement of transversity and 2000 pb -1 on an unpolarised hydrogen target with the new HERMES Recoil Detector to make possible a first measurement of the Generalised Parton Distributions (GPDs). To achieve these goals, DESY will support HERA and its experiments at the present level until the completion of the HERA programme (end 2006 to mid 2007). Global Linear Collider During the last few years, a worldwide consensus among particle physicists has emerged that a 500 GeV electron-positron linear collider (LC) should be the next big project in the field. This collider should be constructed with an initial centre-of-mass energy of 500 GeV, upgradeable to around 1 TeV. The international consensus is based upon evaluations of the future of Particle Physics which were done independently in three regions of the world, the Americas, Asia, and Europe. During 2003, this consensus was formulated in a document which has received widespread support from the international Particle Physics community. Over the last decade, DESY has, with the TESLA collaboration, developed linear collider technology based on superconducting cavities and has worked on the physics case for such a machine. These studies culminated in the presentation of the TESLA Technical Design Report in DESY has been a driving force in rendering the linear collider a truly international machine, e.g. in proposing

20 novel concepts like the Global Accelerator Network (GAN). DESY also contributed significantly to the first conceptual design of a LC detector and to the identification of the detector components where significant R&D is required in order to fully exploit the physics opportunities of the LC. R&D on these detectors, which is coordinated at a global level, has started and first results have been obtained. The linear collider, whether at DESY or elsewhere, is the central project for Elementary Particle Physics at DESY in the future. External experiment Between the end of the HERA programme and the start of experimentation at a LC, DESY wants to remain an attractive Particle Physics laboratory. In addition to the analysis of HERA data and the preparations for the LC, access to new physics data from a first-rate Particle Physics experiment is important. Together with the German universities, DESY is exploring several options for obtaining such data which are commensurate with the available resources, the timing and the interests of the groups involved. The programme should enable German university groups to contribute to an experimental activity in which they otherwise could not participate. A decision, which will be guided by a number of physics workshops, will be reached by LHC-grid computing German Particle Physics groups are heavily involved in the preparation of the four big experiments ALICE, ATLAS, CMS and LHCb at the Large Hadron Collider (LHC) currently under construction at CERN and scheduled to start operation in In addition, there is a strong German commitment to the experiments BaBar, CDF, D0 and COMPASS. These high rate experiments in particular those at the LHC produce unprecedented amounts of data and thus demand computing resources beyond the reach of conventional technology. Providing transparent and efficient access to this data for more than 5000 collaborators from about 300 institutes in 50 countries poses a major challenge, to be met by the grid computing paradigm. The grid, a global network of CPU clusters each comprising thousands of CPUs and petabyte (Pbyte) storage capacity, is presently being developed by the LHC computing centre at CERN (Tier 0) and a number of global distributed Tier 1 centres. The latter serve the lower hierarchy Tier 2, 3 etc. centres around the world (universities, laboratories, institutes, groups, etc.). These developments are coordinated within the international LHC Computing Grid (LCG) project. In addition to setting up and operating the network, a major task of the grid project is the development of the appropriate software infrastructure ( middleware ) which must authorise access to and manage the safe and secure sharing of computing resources worldwide. On the request of, and in close collaboration with, the German Particle Physics community, FZK has taken up the task of developing, installing and operating the Grid Computing Centre Karlsruhe (GridKa) as the German Tier 1 centre of the LCG. This centre also provides the current computing needs of the German BaBar groups and others. The build-up of the necessary infrastructure and hardware started in 2002 and should be completed by Given the lifetime of the LHC experiments, GridKa is expected to operate for at least 15 years. GridKa collaborates closely with the international user community and the members of the LCG project at CERN, in Europe, Asia and the US. In addition to hardware installations and their failsafe operation at FZK, DESY and GSI contribute substantially to the development of software tools and hardware components for this new worldwide scientific computing infrastructure

21 2.4 Integrative aspects Experimental Particle Physics is increasingly coordinated on a world-level, as the size and complexity of the facilities are growing. These facilities are frequently unique on a world-scale, originating from a broad initiative of scientific users who are involved in the development, planning and construction. Scientists from universities and laboratories join forces in the planning, development, and operation of these facilities, which are outstanding examples of national and international research collaborations and scientific networks. One essential feature in the operation of large-scale facilities is that of linking high-ranking scientific research closely with the training of junior scientists and including them in international research collaborations. Experimental Particle Physics Experimental Particle Physics proceeds in large, international collaborations typically collaborators per experiment at HERA and up to 2000 for the large LHC experiments. Scientists from various laboratories and institutions join to shape on the scientific plans, the realisation of the required detector, and the sharing of responsibilities for the components. Proposals for experiments are submitted to the Physics Review Committee (PRC) of the laboratory where the experiments will be performed and to the national funding agencies. The PRC, composed of external scientists, scrutinizes the scientific merit and feasibility, and makes recommendations to the management of the laboratory and the funding agencies. After approval, the PRC follows critically the construction and exploitation of the detector, as well as possible detector improvements and extensions of the scientific programme. The recorded data are available to all members of the collaboration. The collaborations decide on their management structure. Typically they are headed by an elected spokesperson and are governed by an executive committee. The agreements between the partner institutes are formalized in the form of written Memoranda of Understanding. A Particle Physics detector consists of a number of components and central infrastructure, including data acquisition and control. Subgroups take the responsibility for building, maintaining and making available the analysis software for the subcomponents. Common responsibilities, as well as shift duties to operate the detector are shared by all members of the collaboration. The reliable operation of a large particle detector requires that a sizable number of physicists (typically 100 for the HERA experiments) spend a significant fraction of their time at the experiment. The analysis of the data and their physics interpretation is performed in smaller subgroups. Exchange of information and scientific discussions take place in larger physics groups, which are frequently chaired by young scientists. At collaboration meetings, which take place about three times a year, both at the accelerator laboratory and at the collaborating institutions, the scientific results are discussed and the planning is made. A large Particle Physics experiment offers many attractions and challenges for students and young scientists: exciting scientific questions, the possibility to demonstrate scientific excellence and leadership, work in an international team with clearly defined responsibilities (budget, time lines, performance), and access to the most modern tools in experimentation and computing. In short, an ideal environment for an exceptionally broad education and preparation for a later career in the private sector, academia or governmental services. Computing for Particle Physics Given the extraordinary needs for communication and large scale computing, Particle Physics always has and is playing a prominent role in the developing innovative IT concepts. Examples are the com