Presentation at NEPPSR August 21 st 2003 by

Presentation at NEPPSR August 21 st, 2003 by Professor Homer Neal (Yale) What is a linear collider and what can it do The role of a LC in the LHC era The NLC/JLC/TESLA linear collider R&D & Detector(s) Steps to fruition - H. Neal

- H. Neal

Why leptons? The proton is not a simple object This is a bit of an exageration because it is Au on Au but its not far from the truth Why electrons and not muons or tau leptons? Muon decay creates currently insurmountable difficulties like neutrino radiation. Taus are even worse. Why linear? Small mass particles lose a lot of energy when accelerated in a circle at high energies. Energy loss per turn: Loss 1013 worse for e than p - H. Neal

Large Hadron Collider: Good luminosity and “easy” to get to high energies but with low energy precision and no beam polarization Challenges: high event rate and radiation level Lepton collider: Colliding bare partons collision energy precisely known, polarizatio controlable, collision point well determined, energy tunable Lower event rates and backgrounds but still a challenge for precise/ delicate inner detectors - H. Neal

An Example of Beautiful Clean Physics at a Lepton Linear Collider - H. Neal

To this Note: Full NLC length not shown!!! From this ~25 km long! - H. Neal

Justifications for the push to have higher energy colliders We still haven't found the Higgs and it is essential for understanding how the particle masses are generated There are many indications of the existence of new physics accessible at the next generation of colliders: Dark matter - what is the source of all that matter (SUSY CDM may be the answer) Dark energy - why cannot we fully explain "the“ accelerating universe Matter dominance - If Ba. Bar/Belle measurements continue to match the SM predictions, we've got a problem. (can we detect CP violation in the lepton sector) a cosmological time dependence (maybe some clues from precision high energy measurements) - H. Neal

- H. Neal

Why all the Hoopla Concerning Models like SUSY Solves naturallness problem: Divergent terms are automatically cancelled by terms from the superpartners: potentially unifies SM forces including gravity includes a Higgs mechanism with a heavy top predicted provides a dark matter candidate could potentially have strong enough CP violation to explain observed matter dominance - H. Neal

Sparticle Spectrums for various SUSY Model Parameter Sets reaction Point 1 Ge. V 2 Ge. V 3 Ge. V 4 Ge. V 5 Ge. V 6 Ge. V c 1 0 336 90 160 244 92 c 1 0 c 2 0 494 489 142 228 355 233 c 1 + c 1 - 650 642 192 294 464 304 c 1 + c 2 - 1089 858 368 462 750 459 e e/ m m 920 922 422 1620 396 470 t t 860 850 412 1594 314 264 Zh 186 207 160 203 184 203 Z H/A 1137 828 466 950 727 248 H+ H - 2092 1482 756 1724 1276 364 q q 1882 1896 630 1828 1352 1010 - H. Neal

Even if you don't believe in SUSY or even in the Higgs, it is essentially impossible to construct a model where there is not some new physics that will be discovered by the future colliders. Answers/Resolutions to these issues will results from discovery of new physics along with precision measurements that will elucidate what model is the correct model of nature. - H. Neal

Conclusions from: "The Case for a 500 Ge. V e+e- Linear Collider" All known models with a fundamental Higgs boson satisfy m h < 205 Ge. V Any model using the current EW data that has mh>500 Ge. V predicts other observable new physics phenomena at < 500 Ge. V The lightest SUSY particles are most probable to appear at < 500 Ge. V and all charginos/neutralinos at < 800 Ge. V The observation of no new physics at LHC would increase the necessity of precision EW measurements at the LC - H. Neal

The Justification for a LHC and a LC As in the past, the physics progress greatly benefits from having hadron and lepton machines operating simultaneously. - H. Neal

While the main role of discovery will go to the LHC, the future linear collider will be essential in clarifying what those discoveries are and for measuring the properties of any new particles (mass, spin, couplings). The LC and LHC play a symbiotic role. The discoveries at the LHC will be analyzed by the LC and in term provide feedback essential for further LHC exploration. - H. Neal

Furthermore, there are many measurements/observations that will only be possible at either the LHC or the LC Its quite possible that LHC will see a wealth of signals and will need the lc to determine what some of those are and in turn influence what the lhc running program should be, - H. Neal

There are many competing physics processes and the polarization help to separate and verify processes - H. Neal

- H. Neal

Feeding in LC results in to Analysis Sparticle Masses at LHC From the analysis of SUSY (SPS) point 1 a at ATLAS and CMS Reconstructed masses of squarks and gluinos are correlated to the mass of the neutralino through the analysis of the sparticles in the decay chain Using the measurement of from the LC greatly improves the LHC mass measurement for other sparticles Gjelsten, Lykten, Miller, Osland, Polesello - H. Neal

We thank the Higgs is almost in the bag. . . CMS/ATLAS should easily see it, but they'll need the LC to verify that it is indeed the Higgs and to make precision measurements of its properties. - H. Neal

The Higgs at a LC Measurement of the Higgs branching ratios allows one to verify that it is indeed the Higgs that you've found! e+e-®Zh produces 40, 000 Higgs/year Clean initial state gives precision Higgs mass measurement Model independent Higgs branching ratios - H. Neal

Precission Higgs Mass Measurements Expected Higgs signal at a 500 Ge. V LC for 30 /fb very clean. . very precise - H. Neal

In many parts of the parameter space, only a single Higgs decay mode can be observed by LHC - H. Neal

Extrapolation of the susy mass parameters measured at a LC from the Te. V scale to the grand unification scale. gluinos and squarks mass parameters gaugino mass parameters from selectron measurements Note: Very difficult to do at LHC - H. Neal

- H. Neal

Precision Measurements A LC could run at the Z pole with high luminosity yielding ~Giga Z's per year. Also, there exist the possibility of having a dedicated low energy interaction region detector for either physics at the Z, W-pair or top pair threshold. - H. Neal

extra-dimensions: many theories for Some More Fun Physics explaining the weakness of gravity and even the time evolution of a involve models with an extra-dimension. A LC could observe the pressence of this extra dimension. Physics Today, February, 2002 - H. Neal

- H. Neal

Polarizing the beams P. Saez et al. Much more difficult for positrons!!!! - H. Neal

At issue: An e+e- linear collider operating at about a Te. V with possible upgrade to several Te. V » 1034 cm 2/sec (300 fb-1/yr) with one or two detectors polarized electron beam (Pe = 80%) possibly a polarized positron beam possibly a gamma-gamma collision option either warm or cold acceleration technology A long-term facility with regional control and analysis centers around the globe. - H. Neal

World Wide Effort US/North America Japan (The Asian Committee for Future Accelerators ) Europe (the European Committee for Future Accelerators ) - H. Neal

The Next Linear Collider (NLC) – North American Style Baseline design: 25 km site two 10 km linacs sized for 1 Te. V fill ½ of linacs for 500 Ge. V Final focus, Injector design for 1. 5 Te. V. Possibly two IRs; one for Te. V collisions the other operating upto 500 Ge. V Electron Polarization 80% Possibilities: • Positron polarization • e- e- collision • gg collisions - H. Neal

Next Linear Collider Test Accelerator (NLCTA @ SLAC) Small accelerator prototype The Final Focus Test Beam facility (FFTB @ SLAC) developing and validating the optical design of linear collider final beam focus systems for obtaining stable and extremely narrow beams. Accelerator Test Facility (ATF @ Kou Enerugii Kosokuki Kenkyuu Kikou) A test damping ring for the low emittance beams required for the NLC The Accelerator Structure SETup (ASSET) - H. Neal

A Sample of LC Accelerator Projects (from the Himmel List) ID: 104 project_size: skill_type: short project description: Processing of superconducting half-cells before welding (chemistry, Ti vacuum bake) ID: 116 project_size: skill_type: short project description: Low Level RF System Simulations ID: 95 project_size: small skill_type: physicist short project description: Remote operation of TESLA Test Facility linac at DESY ID: 96 project_size: small skill_type: physicist short project description: Remote operation of Photoinjector Laboratory (FNPL) at Fermilab ID: 97 project_size: skill_type: physicist short project description: Consider needs of LC remote operation system ID: 98 project_size: large skill_type: short project description: Accelerator Control and Machine Protection System (MPS) ID: 99 project_size: small skill_type: materials science short project description: Mechanical properties and microstructure, metallic and interstitial gases, material specification. ID: 100 project_size: skill_type: materials science short project description: RRR issues - hydrogen degassing, Ti firing, low temperature bakeout. ID: 101 project_size: medium skill_type: physicist short project description: Improved scanning of superconducting materials - eddy current, squids ID: 103 project_size: large skill_type: materials science short project description: : Explore the use of materials other than Nb in superconducting cavities, e. g. , Nb 3 Sn. ID: 105 project_size: small skill_type: short project description: TESLA Cavity Flanges and Seals. ID: 111 project_size: skill_type: short project description: low level RF Digital Feedback Hardware - H. Neal

: 75 MW ms : 120 Hz : 1. 6 - H. Neal

Solution found for problem with deterioration at input to acceleration structure!!! - H. Neal

- H. Neal

- from Torr Robenheimer - H. Neal

J L C from: JLC Roadmap Report Draft released February 12, 2003 - H. Neal

TESLA Specifications total length of the facility 33 km (including two 15 -kilometer acceleration sections) accelerator tunnel with approx. 5 m diameter collision energy of 500 Ge. V X-ray wavelength of 5 to 0. 05 nanometer ~20 k superconducting accelerating structures operating temperature of 2 K, i. e. -271 deg Celsius depth underground 10 - 30 meters collision points/particle physics experiments Initially one (expandable to two, in an underground hall) number of cryogenic halls 7 - H. Neal

The Tesla layout taken from the completed TESLA TDR. - H. Neal

The TESLA high gradient superconducting accelerating cavities For a 500 Ge. V center of mass linear collider needs accelerating fields of about 25 MV/m. 800 Ge. V requires about 35 MV/m. cavity frequency 1. 3 GHz; standing wave pi-mode operation temperature 2 K (-271 deg Celsius) cavity bandwidth approx. 400 Hz material: Niobium with high thermal conductivity fabrication technique: * electron beam welding * hydro forming * spinning - H. Neal

A Proposed Schedule for TESLA * studies at the TESLA Test Facility 1999 / 2000 * demonstration of the new SASE FEL principle 1999 / 2000 * complete project proposal, approval 2001 * project ready for final decision * estimated construction time 2001 / 2002 6 to 8 years - H. Neal

Tunnel Route * In order to fully exploit the research potential of the new facility, the TESLA tunnel must b constructed as an exact extension of the western straight section of the HERA accelerator * In other words, the TESLA tunnel will begin on the DESY site in Hamburg and run in a north-northwesterly direction through the district of Pinneberg in Schleswig-Holstein * The electron-positron collision zone lies on the outskirts of Ellerhoop, some 16. 5 kilometers from DESY. When complete, the site will accommodate the underground hall for particle physics experiments and an X-ray laser facility. It will also house various supply and infrastructural facilities * In addition, seven large supply halls, all with access to the tunnel, will be strategically located along the route. - H. Neal

- H. Neal

Free Electron Laser for X-rays Extremely high beam currents would be produced at very low beam emittance, i. e. very high beam quality. The basis of the FEL principle for wavelengths within the nanometer region and below it can be summarized as follows: short electron bunches are made to emit coherent synchrotron radiation while passing through a long undulator - a long magnetic structure with rapidly alternating field directions. The goal of the TTF FEL is a unique source of coherent radiation in the VUV range, i. e. with wavelengths of approx. 6 nanometers. - H. Neal

- H. Neal

US involvement in TESLA * APS/Argonne, Chicago, IL * Cornell University, Ithaca, NY * Fermilab, Batavia, IL * Thomas Jefferson National Laboratory, Newport News, VA * UCLA Dep. of Physics, Los Angeles, LA - H. Neal

A 1 Te. V machine doesn't mean that's its limit. Remember: LEPII got to higher and higher energies during a given run with mini-ramps using a similar concept. Energy and luminosity can be played against each other. D. Burke - H. Neal

Photon-Photon Option would allow: direct production of positive charge parity resonances such the SM Higgs boson production of heavy Higgs bosons with masses < 1. 5 ECM pair production of charged Higgs bosons with 10 x the cross-section for electron-positron collisions - H. Neal

Upgrade Paths Pulse structure most suitable for adding onto a warm LC. - H. Neal

The LC Detector(s) TESLA detectors - H. Neal

Detector Challenges in Comparison to those for ATLAS/CMS http: //blueox. uoregon. edu/~lc/randd. html 3 -6 times closer inner vertex layer to the IP (higher vertexing precision), 30 times smaller vertex detector pixel sizes (improved position resolution andtwo-track resolution), 30 times thinner vertex detector layers (reduced multiple scattering and photon conversions), 6 times less material in the tracker (better momentum resolution and reduced photon conversions), 10 times better track momentum resolution (better event selection purity) and 200 times higher granularity of the electromagnetic calorimeter, enabling sophisticated energy flow algorithms. However, the radiation hardness requirements are significantly less than at the LHC. - H. Neal

The NLC Large Detector Current Model - H. Neal

- H. Neal

Large Detector Tracking Systems - H. Neal

The Vertexing as an Example of Required R&D The detector has to be made tolerant to the e+e- pairs produced at whatever radius is chosen. levels at JLC/NLC/TESLA expected to be 100 to 1000 x higher than at SLC the neutron backgrounds are expected to be ~3 x 108 neutrons/cm 2/sec (also 100 to 1000 x higher than at - H. Neal

The background and bunch structure stress the vertex detector readout Background in VXD at 1. 5 cm with B=3 Tesla 4 x 10 -6 hits/pixel/bunch(NLC/JLC), 12 x 10 -6 hits/pixel/bunch(TESLA) ·Requirement for NLC/JLC ~8 msec readout time ·Requirement for TESLA ~50 msec (due to large number of bunches in a pulse train) ·Expect to achieve a readout rate of 25µ 50 MHz ·Remaining factor of improvement can be obtained from increasing the number of readout channel VXD: 4 JLC/NLC: ~36 for 25 MHz TESLA: ~3000 readout amplifiers at 50 Mhz - H. Neal

The detectors have to be thinned to reduce multiplescattering and sensitivity to backgrounds. Have to find a way to support thinned structures without break them! - H. Neal

- H. Neal

Estimated Detector Costs - H. Neal

International Organizing Committee of the Worldwide Study of Physics and Detectors for Future Linear e+e - Colliders Co-chairs * Charles Baltay, Yale University * Sachio Komamiya, University of Tokyo * David Miller, U. C. London North American Committee Members * Jim Brau, University of Oregon (USA) * Robert Carnegie, (Canada) * Paul Grannis, SUNY, Stony Brook (USA) * Mark Oreglia, University of Chicago (USA) * Charles Prescott, SLAC (USA) Asian Committee Members * Shinhong Kim, Tsukuba University (Japan) * Joo Sang Kang, Korea University Seoul (Korea) * Takayuki Matsui, KEK (Japan) * G. P. Yeh, Taiwan * Tao Huang, University of Beijing (China) European Committee Members * Michael Danilov, ITEP (Russia) * Rolf Heuer, CERN/DESY (Germany) * Marcello Piccolo, Frascati (Italy) * Francois Richard, Orsay (France) * Ron Settles, Munich (Germany) - H. Neal

The American Linear Collider Physics Group Leaders: " Jim Brau (U. Oregon, jimbrau@faraday. uoregon. edu) " Mark Oreglia (U. Chicago, oreglia@hep. uchicago. edu) Executive committee: 1 Ed Blucher (University of Chicago, blucher@hep. uchicago. edu) 1 Dave Gerdes (University of Michigan, gerdes@umich. edu) 1 Lawrence Gibbons (Cornell, lkg@mail. lns. cornell. edu) 1 Dean Karlen (University of Victoria, karlen@uvic. ca) 1 Young-Kee Kim (University of California, Berkeley, ykkim@lbl. gov) 1 Hitoshi Murayama (University of California, Berkeley, murayama@hitoshi. berkeley. edu) 1 Jeff Richman (University of California, Santa Barbara, richman@hep. ucsb. edu) 1 Rick Van Kooten (Indiana University, rickv@paoli. physics. indiana. edu) - H. Neal

Groups within the ALCPG Detector and Physics Simulations Vertex Detector Tracking Particle I. D. Calorimetry Muon Detector Data Acquisition, Magnet, and Infrastructure Interaction Regions, Backgrounds: Stan Hertzbach IP Beam Instrumentation Higgs SUSY New Physics at the Te. V Scale and Beyond Radiative Corrections (Loopverein) Top Physics, QCD, and Two Photon Precision Electroweak gamma-gamma, e-gamma Options e-e LHC/LC Study Group - H. Neal

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Getting support from DOE for University LC R&D - H. Neal

Globalisation - H. Neal

DESY PRESS INFORMATION, Hamburg, November 18, 2002 German Science Council Recommends International Accelerator Project TESLA The German Science Council, an agency of the German government, assessed the TESLA project planned by the research center DESY in cooperation with international partners to, be worthy of support under certain conditions. The assessments of nine appraised large scale facilities for basic research in the natural sciences have been published today. "We are very glad that the Science Council changed its first positive statement about TESLA to the German federal government to a recommendation, and we are looking forward to hear the upcoming evaluations" said Professor Albrecht Wagner, chairman of the DESY Directorate, "since we have complied with the conditions posed by the Science Council". The Science Council listed two conditions in its first evaluation statement: to detail the project proposal for the superconducting electron-positron linear collider with respect to international funding and cooperation, and to present a revised technical project proposal for the TESLA X-ray laser version with a separate linear accelerator. In October, DESY sent the corresponding papers to the Science Council: a draft for the administrative, organizational and financial structures of an international linear collider collaboration and a complementary technical project proposal for the X-ray laser as well as a respective memorandum for each theme, including the current scientific-political developments. These papers will influence the further evaluation. The final decision of the federal government regarding the TESLA project is expected in 2003. TESLA stands for Te. V-Energy Superconducting Linear Accelerator - a particle accelerator facility operating at teraelectronvolt energy which is being developed in an international collaboration. TESLA comprises of a 33 -kilometer-long linear accelerator bringing electrons into collision with their antiparticles, the positrons, and an X-ray laser laboratory. The special feature of the new facility: A new type of superconducting accelerators allow collisions between particles at an extremely high level of energy and serve as a source of intense and extremely short X-ray flashes with laser properties. The TESLA X-ray lasers will offer new perspectives for research in different disciplines - from physics and chemistry to biology, materials research and medicine. TESLA is to be established - H. Neal

Here is a translation of today's press release from the German Federal Ministry for Education and Research. See http: //www. bmbf. de/presse 01/798. html for the original. Andreas Kronfeld BULMAHN GIVES GREEN LIGHT TO LARGE-SCALE FACILITIES thereby ensuring Germany's international top position in basic research [Edelgard Bulmahn is the minister for research. There are four paragraphs in which she says how important basic research in science is for Germany. I don't have time to translate it all. It says that 1. 6 Billion Euro are planned for large projects, and that these large projects require close international cooperation. Scroll down to ``Entscheidung über die Großgeräte der naturwissenschaftlichen Grundlagenforschung'', and I'll start from there. ] Decision on Large-scale Facilities for Basic Research in the Natural Sciences. . . . - The reseach center DESY in Hamburg shall receive a new kind of free electron laser. Because of the location of the site, Germany is prepared to carry half of the 673 million Euro investment cost. Discussions on European cooperation will proceed expeditiously, so that in about two years a construction decision can be taken. Constructionwill take about six years. Today no German site for the TESLA linear collider will be put forward. This decision is connected to plans to operate this project within a world-wide collaboration. Therefore, one must wa on developments abroad. On the question of site, it is neither sensible nor necessary for Germany to act alone. DESY will, however, be allowed to continue its research work [on TESLA] in the existing international framework, to facilitate German participation in a future global project. - H. Neal

The decisions of the German Ministry for Education and Research concerning TESLA was published on 5 February 2003: TESLA X-FEL DESY in Hamburg will receive the X-FEL Germany is prepared to carry half of the 673 MEuro investment cost. Discussions on European cooperation will proceed expeditiously, so that i about two years a construction decision can be taken. TESLA Collider Today no German site for the TESLA linear collider will be put forward. This decision is connected to plans to operate this project within a worldwide collaboration DESY will continue its research work on TESLA in the existing international framework, to facilitate German participation in a future global project - H. Neal

Consequences for the LC 'The path chosen by TESLA to move towards approval was recommended by the German Science Council and is generally considered to be the fastest one. 'Community will now take the other path used for international projects (e. g. ITER): unite first behind one project with all its aspects, including the technology choice, and then approach all possible governments in parallel in order to trigger the decision process and site selection. 'ICFA initiative for an international co-ordination: Asian SG Gov US SG Gov European SG Gov ECFA International LC SC - H. Neal

WMAP Auger PLANCK GLAST Tevatron LHC 2003 2007 LISA 2010 SNAP/LSST LHC Upgrade 2012 2015 2018 2020 LC: Phase I J. Hewett - H. Neal

Reconstructing the Higgs Potential ~ V( H) = m. H 2/2 + v H 3 + H 4/4 Baur, Plehn, Rainwater ~ Assume = = SM = m. H 2 /2 v 2 Higgs self-coupling determined with better accuracy at: • LC for m. H < 140 Ge. V • LHC for m. H > 140 Ge. V LHC measurements improve with LC input on Higgs properties - H. Neal

Specific US Issues What is the future for physics in the US? ? If the only possibility is to build the facility in europe or Japan, will the US government provide its share of the funding for a facility abroad? Will the US physicists being content having the only major HEP facilities outside the country? What will become of Fermilab? What will SLAC's role be even if the facility is built in the US? How do you invision using the regional centers for students? How to make the case to the government? - H. Neal

University LC Accelerator & Detector R&D Funding Individual Investigator's Desires Guidance on projects from Rogers, Himel, and Finley Consortia Proposals Funding profile from NSF Accelerator Review Committee NSF Consortium Funding profile from DOE Prioritized Recommendations NSF Guidance on priorities from U. S. Physics & Detector Group (Oreglia & Brau) and International Group (Hoyer et al) Detector Review Committee DOE Consortium DOE $ $ Individual Investigators July 14, 2003 American Linear Collider Workshop - H. Neal

(from HEPAP report) RECOMMENDATION 1: We recommend that the United States take steps to remain a world leader in the vital and exciting field of particle physics, through a broad program of research focused on the frontiers of matter, energy, space and time. The U. S. has achieved its leadership position through the generous support of the American people. We renew and reaffirm our commitment to return full value for the considerable investment made by our fellow citizens. This commitment includes, but is not limited to, sharing our intellectual insights through education and outreach, providing highly trained scientific and technical manpower to help drive the economy, and developing new technologies that foster the health, wealth and security of our nation and of society at large. RECOMMENDATION 3: We recommend that the highest priority of the U. S. program be a high-energy, high-luminosity, electron-positron linear collider, wherever it is built in the world. This facility is the next major step in the field and should be designed, built and operated as a fully international effort. We also recommend that the United States take a leadership position in forming the international collaboration needed to develop a final design, build and operate this machine. The U. S. participation should be undertaken as a partnership between DOE and NSF, with the full involvement of the entire particle physics community. We urge the immediate creation of a steering group to coordinate all U. S. efforts toward a linear collider. - H. Neal

Words of Motivation from Neil Calder: In the last 10 years there has been a revolution in our concept of the Universe and the realities of our new knowledge are much stranger than could have been imagined. The ingredients of our universe were first accurately measured as recently as March this year. The results are staggering - 4% Atoms, 23% Dark Matter, 73% Dark Energy. The implications of this new understanding are enormous. We, and everything we can see with our most powerful instruments, make up only 4% of the Universe. We are a tiny minority. The rest is waiting to be discovered. We are at a turning point in the history of knowledge. Has there ever been more compelling challenge for exploration? The Linear Collider is the key to understanding this weird and wonderful universe that we inhabit. Making precise measurements is the name of the game and only accelerator based experiments can provide the controlled conditions needed to make sense of the new cosmological observations. Measure, measure is the imperative for historic discoveries! The Linear Collider will not only investigate new frontiers in physics and technology but also in international science collaboration. This project will go ahead as a closely coordinated international collaboration, with shared costs and shared benefits, on a scale and scope never before seen in science. The US is the world’s foremost scientific nation. Participation in the Linear Collider will reinforce this leadership and give our young scientists the challenge of taking part in the most exciting scientific quest of the 21 st century. - H. Neal

Its an exciting time for high-energy physics and its exploration through a new generation of high-energy colliders The case for a high energy e+e- LC is strong There are many opportunities for research and development and a new push is being made to reenergize the effort in the US While the path through the red-tape is not obvious and serious thought is needed, the main focus should be on the importance of the physics and the thorough design of the accelerator and detector. - H. Neal