Physics Opportunities at a Muon Collider

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The Muon Collider in the News.
Bibliography of muon collider accelerator physics prior to 1995.

The following are in order of appearance, most recent first.
1/28/00, E.G. Bessonov, Cooling of Particle Beams in Storage Rings .
3/99, Manpower needs of R&D for detector simulation for the Muon Collider , V. Barger et al. (Mar. 3, 1999).
12/98, Radiological hazard due to neutrinos from a muon collider, C. Johnson, G. Rolandi and M. Silari, CERN/TIS-RP/IR/98-?.
10/98, Future Accelerators, K. Hubner, CERN-SL-98-065 DI.
6/98, Options for Future Colliders at CERN, J. Ellis.
6/98, Muon Colliders, An Invitation to Further Study, A. Blondel.
5/98, The Muon Collider Project , B. King.
5/98, Bileptons from Muon Collider Backward Scattering , P.H. Frampton and X.Guan.
4/98, The Muon Collider, Physics Opportunities, Technical Challenges , K.T. McDonald.
4/98, Higgs and Technicolor Goldstone Bosons at a Muon Collider , J.F. Gunion.
4/98, CP Violation, Higgs Couplings, and Supersymmetry , K.S. Babu, C. Kolda, J. March-Russell and F. Wilczek.
4/98, Quartic Gauge Boson Couplings , H.-J. He.
4/98, The Ultimate Neutrino Beams: Neutrino Physics at Muon Colliders , B. King.
4/98, Muon Colliders: New Prospects for Precision Physics & the High Energy Frontier , B. King.
4/98, A Small Target Neutrino Deep-Inelastic Scattering Experiment at the First Muon Collider , D.A. Harris and K.S. McFarland.
4/98, Detectors for Neutrino Physics at the First Muon Collider , D.A. Harris and K.S. McFarland.
3/98, Testing 2HDM at Muon Colliders , M. Krawczyk.
3/98, Overview of Physics at a Muon Collider , V. Barger.
3/98, Strong Dynamics at the Muon Collider: Working Group Report , P. Bhat and E. Eichten.
3/98, Sparticle Masses from Kinematic Fitting at a Muon Collider , J.D. Lykken.
3/98, Physics with a Millimole of Muons, Chris Quigg.
3/98, Probing Exotic Higgs Sectors in Lepton-Lepton Collisions , J.F. Gunion.
2/98, Narrow Technihadron Production at the First Muon Collider , E. Eichten, K. Lane and J. Womersley.
2/98, Supersymmetry vis-a-vis Muon Colliders , V. Barger.
2/98, Top quark physics at muon and other future colliders , M.S. Berger and B.L. Winer.
2/98, Top Quark Physics at a Polarized Muon Collider , S. Parke.
2/98, Precision measurements of threshold chargino production , M.S. Berger.
2/98, Testing Technicolor with Scalars at the First Muon Collider , B.A. Dobrescu.
2/98, Physics at a Muon Collider , J.F. Gunion.
2/98, Topcolor and the First Muon Collider , C.T. Hill.
2/98, Gluon Radiation in Top Production and Decay at Lepton Colliders , L.H. Orr.
2/98, Threshold cross section measurements , M.S. Berger.
2/98, Muon Collider: Introduction and Status , R.B. Palmer.
1/98, Physics at Muon Colliders , V. Barger.
1/98, Chargino mass determination at a muon collider , V. Barger, M.S. Berger and T. Han.
1/98, Higgs Boson and Z Physics at the First Muon Collider , M. Demarteau and T. Han.
1/98, Leptons at a First Muon Collider , F.E. Paige.
1/98, SUSY Before the Next Lepton Collider , F.E. Paige.
1/98, Technicolor and the First Muon Collider , K. Lane.
1/98, Determining the Coupling of a Higgs Boson to ZZ at Linear Colliders , J.F. Gunion, T. Han and R. Sobey.
1/98, Top Quark Pair Production at Higher Energies at the First Muon Collider , A.H. Hoang.
1/98, Compositeness Test at the FMC with Bhabha Scattering , E.J. Eichten and S. Keller.
1/98, R-Parity Violation and Sneutrino Resonances at Muon Colliders , J.L. Feng.
1/98, A Strong Electroweak Sector at Future mu+mu- Colliders , R. Casalbuoni et al.
1/98, Coherent muon-electron conversion in muonic atoms , A. Czarnecki, W.J. Marciano and K. Melnikov.
1/98, Calibrating the energy of a 50 X 50 GeV muon collider using spin precession, R. Raja and A. Tollestrup.
1/98, Options for Future Colliders at CERN, J. Ellis, E. Keil and G. Rolandi (CERN-SL-98-004, 400kB, PDF).
12/97, The Top-Antitop Threshold at Muon Colliders, M.S. Berger.
12/97, Probing Anomalous Higgs Coupling through mu+ mu- --> H gamma, A. Abbasabaddi et al.
12/97, Physics at Future Colliders, J. Ellis.
12/97, Measuring Trilinear Gauge Boson Couplings at Hadron and Lepton Colliders, U. Baur.
12/97, Neutrino beams from muon storage rings: Characteristics and physics potential , S. Geer, Phys. Rev. D 57, 6989 (1998).
12/97, Precision Measurements at The Higgs Resonance: A Probe of Radiative Fermion Masses, F.M. Borzumati et al.
12/97, Flavor and CP violations from sleptons at the muon collider, H.C. Cheng.
12/97, Flavor Changing Neutral Currents at mu^+mu^- Colliders, Laura Reina.
12/97, Scalar Top Quark Production at mu^+ mu^- Colliders, A. Bartl et al.
12/97, Higgs Resonance Studies At The First Muon Collider, B. Kamal, W.J. Marciano and Z. Parsa.
12/97, Neutrino Physics at a Muon Collider, B. King.
11/97, Neutrino Physics in a Muon collider, R.N. Mohapatra.
11/97, R-Parity Violation and Sneutrino Resonances at Muon Colliders , J.L. Feng, J.F. Gunion and T. Han.
11/97, Photon Scattering in Muon Collisions , M. Klasen.
11/97, Higgs Factory mu+mu- Collider and the Scalar Electroweak Sector , D.B. Cline, Int. J. Mod. Phys. A13, 183 (1998).
11/97, Long Baseline Neutrino Ideas Using an Intense Muon Source , S. Geer.
8/97, Muon Collider Physics , J.F. Gunion.
7/97, Muon Colliders: The Machine and The Physics , J.F. Gunion.
5/97, Detecting and Studying Higgs Bosons , J.F. Gunion.
4/97, Muon Colliders: A Fixed Target Physicists Dream ? , S. Geer.
4/97, Radiative corrections to the lineshape of a heavy Higgs boson at muon colliders , T. Binoth and A. Ghinculov.
4/97, The Physics Capabilities of mu^+ mu^- Colliders , V. Barger et al.
4/97, Strong WW Scattering Physics: A Comparative Study for the LHC, NLC and a Muon Collider , T. Han.
3/97, Muon Collider Detector and Backgrounds , S. Geer.
3/97, Higgs Physics at a Muon Collider , J.F. Gunion.
2/97, Physics at the Front-End of a Muon Collider , S. Geer.
2/97, Precision W-boson and top-quark mass determinations at a muon collider , V. Barger et al.
10/96, The Problems and Physics Prospects for a mu+mu- Collider, D.B. Cline, AIP Conf. Proc. Vol. 397, 203 (1997).
10/96, The Physics Capabilities of mu+mu- Colliders, V. Barger et al., AIP Conf. Proc. Vol. 397, 219 (1997).
7/96, Muon Collider Detector Issues and Ideas , S. Geer.
6/96, New Directions for High Energy Physics, ed. by D.G. Cassel, L.T. Gennari and R.H. Siemann, (Snowmass, CO, June 1996).
6/96, Mu-Mu collider: a Feasibility Study , the 1996 Snowmass book, available in chapters.
6/96, Studying a Strongly Interacting Electroweak Sector via Longitudinal Gauge Boson Scattering at a Muon Collider , V. Barger et al.
5/96, Physics Motivations for a Muon Collider , J.F. Gunion.
3/96, Resonant CP-Violating Scalar-Pseudoscalar Transitions at mu+mu- Colliders , A. Pilaftsis, Phys. Rev. Lett. 77, 4996 (1996).
12/95, Proceedings of the Symposium on Physics Potential and Development of mu+mu- Colliders (San Francisco, Dec. 1995), Nucl. Phys. B (Proc. Suppl.) Vol. 51A (1996).
12/95, Precision Measurements at a Muon Collider , S. Dawson.
10/95, Beam Dynamics and Technology Issues for mu+mu- Colliders, 9th Advanced INCFA Beam Dynamics Workshop (Montauk, NY, Oct. 1995), AIP Conf. Proc. Vol 372 (1996).
8/95, Physics with Like-Sign Muon Beams , F. Cuypers and C. A. Heusch.
8/95, The ttbar threshold at a muon collider , M.S. Berger.
4/95, s-Channel Higgs Boson Production at a Muon-Muon Collider , V. Barger et al.
3/95, Physics Goals of a Muon Collider, V. Barger et al.
12/94, Physics Potential and Development of mu+mu- Colliders, 2nd Workshop on Muon Colliders (Sausalito, CA, Dec. 1994), AIP Conf. Proc. Vol. 352 (1995).

Prior to 1994, most discussions related to the accelerator physics of muon colliders. As the development of accelerator physics is underdocumented, but vital for high-energy physics, the bibliography below attempts to trace the origins of the ideas on which the muon collider is based. See also, Scans of early muon collider papers.
6/01, Feasbility Study-II of a Muon-Based Neutriono Source, S. Ozaki et al.
6/96, Mu-Mu collider: a Feasibility Study, the 1996 Snowmass book, available in chapters.
12/94, Some Comments on the Early History of the μ+μ- Concept and the High Intensity &mu: Storage Ring, D. Cline, AIP Conf. Proc. 352, 3 (1996).
11/94, Progress Toward A High-Energy, High-Luminosity μ+μ- Collider, D. Neuffer and R.B. Palmer, AIP Conf. Proc. 356, 344 (1996).
7/94, A High-Energy High-Luminosity Muon Collider, D.V. Neuffer and R.B. Palmer, EPAC94, p. 52.
6/94, A Practical High-Energy High-Luminosity Muon Collider, R.B. Palmer, D.V. Neuffer and J. Gallardo, AIP Conf. Proc. 335, 635 (1995).
2/93, Proceedings of the Muon Collider Workshop, Los Alamos report LA-UR-93-866 (Feb. 1993).
12/92, Physics potential of a few hundred GeV μ+μ- collider, D.B. Cline, Nucl. Instr. and Meth. A350, 24 (1994).
12/92, μ+μ- colliders: possibilities and challenges, D.V. Neuffer, Nucl. Instr. and Meth. A350, 27 (1994).
12/92, Characteristics of a high energy μ+μ- collider based on electro-production of muons, W.A. Barletta and A.M. Sessler, Nucl. Instr. and Meth. A350, 36 (1994).
12/92, A muon collider scenario based on stochastic cooling, A.G. Ruggiero, Nucl. Instr. and Meth. A350, 45 (1994).
12/92, Critical issues in low energy muon colliders - a summary, S. Chattopadhyay et al., Nucl. Instr. and Meth. A350, 53 (1994).
6/92, Summary of the Physics Opportunities Working Group, P. Chen and K.T. McDonald, AIP Conf. Proc. 279, 853 (1993).
6/92, Particle Production and Survival in Muon Acceleration, R.J. Noble, AIP Conf. Proc. 279, 949 (1993).
6/92, The Muon Collider (Sandro's Snake), A.G. Ruggerio, AIP Conf. Proc. 279, 958 (1993).
8/86, Multi-TeV Muon Colliders, D. Neuffer, AIP Conf. Proc. 156, 201 (1987). This may be the first mention of the advantage of a mu+mu- collider over an e+e- collider in s-channel Higgs production.
8/83, Ionization Cooling: Physics and Applications, V.V. Parkhomchuk and A.N. Skrinsky; also in AIP Conf. Proc. 352, 7 (1996).
2/83, Principles and Applications of Muon Cooling, D. Neuffer; also in AIP Conf. Proc. 352, 12 (1996); also Part. Acc. Vol. 14, 75 (1983).
9/82, Accelerator and detector prospects of elementary particle physics, A.N. Skrinsky, Sov. Phys. Usp. Vol. 25, 639 (1982).
5/81, Methods of cooling beams of charged particles, A.N. Skrinsky and V.V. Parkhomchuk, Sov. J. Part. Nucl. Vol. 12, 223 (1981).
80, Accelerator and Instrumentation Prospects of Elementary Particle Physics, A.N. Skrinsky, AIP Conf. Proc. 68, 1056 (1981).
80, A Muon Storage Ring for Neutrino Oscillation Experiments, D. Cline and D. Neuffer, AIP Conf. Proc. 68, 846 (1981); also AIP Conf. Proc. 352, 10 (1996). This may be the first discussion of the advantages of neutrino beams produced from the decay of muons in a storage ring.
7/79, Colliding Muon Beams at 90 GeV, D. Neuffer, FN-319.
4/78, Electron cooling and new possibilities in elementary particle physics, G.I. Budker and A.N. Skrinski, Sov. Phys. Usp. 21, 277 (1978).
3/71, Intersecting Storage Rings at Novosibirsk, A.N. Skrinsky, seminar at Morges (1971); extract in AIP Conf. Proc. 352, 6, (1996). Mentions that the absorber for ionization cooling should be placed at a low-beta point.
70, G.I. Budker, High Energy Phys. Conf. (Kiev, 1970), unpublished; extract in AIP Conf. Proc. 352, 4, (1996). This adds the remark that the muon phase volume can be reduced by inserting a target inside the storage ring -- i.e., by ionization cooling.
5/70, Use of Ionization Friction in the Storage of Heavy Particles, Yu.M. Ado and V.I. Balbekov, Sov. Atomic Energy 31, 731 (1971). The first published analysis to conclude that ionization cooling might actually work -- particularly if liquid hydrogen is used as the absorber. Note: because of the small print used in this journal, I had to scan the articles at 300 dpi => files are ~150 kB each, and the whole image doesn't fit on screen at one time. You might wish to capture the .gif files and use a graphics program to print them...
8/69, Accelerators and Colliding Beams (in Russian), G.I. Budker, Proc. of the 7th Int. Conf. (Yerevan, 1969), p. 33; extract in AIP Conf. Proc. 352, 4, (1996). This appears to be the first mention of muon collisions in storage rings. The famous invariance of the number of turns a muon lives in rings of a given magnetic field is first stated here.
68, On the Effects with Muon Colliding Beams, F.F. Tikhonin, JINR Report P2-4120 (Dubna, 1968). This may be the first mention of particular physics interest in mu+mu- collidsions. `The possible effect of the weak interaction on mu+mu- -> mu+mu- and mu+mu- -> e+e-, both through neutral lepton currents and charged ones (in the 2nd order of the weak constant) is considered. The calculations show that P-odd effects would prove the existence of neutral currents which, in their turn, give the principal basis for an explanation of the mass difference of a muon and an electron from the point of view of M.A. Markov, JETP Lett. Vol. 3, 62 (1966).'
12/66, An Effective Method of Damping Particle Oscillations in Proton and Antiproton Storage Rings, G.I. Budker, Sov. Atomic Energy 22, 438 (1967). In response to Kolomensky's discussion of ionization cooling, Budker concludes like Lichtenberg et al. that multiple scattering would mask any cooling. He then gives the first published analysis of electron cooling (which is a variant of ionization cooling) -- as a means of avoiding the problem of multiple scattering in ionziation cooling of protons beams.
9/66, Status Report of Works on Storage Rings at Novosibirsk, G.I. Budker, Proc. Int. Symp. on Colliding Rings (Saclay, Sept. 1966), p. II-1-1. This may be the first published mention of electron cooling, which idea Budker credits to O'Neill (and his colleagues). Ionization cooling is not mentioned.

Comment by Fred Mills (Feb 21, 2008):
"In 1976 at Fermilab we began investigating cooling for p-pbar colliders. Shortly thereafter Milton White of Princeton, who was a member of the URA Board, told me about a need to reduce the emittance of a beam from a van de Graaff for injection into the Princeton Pennsylvania Accelerator. This was discussed at a faculty lunch and Lyman Spitzer (a well-known plasma physicist) suggested a moving electron plasma, i.e., electron beam, with which to equilibrate the proton beam. Gerry O'Neill, or a student, did some calculations which showed that the process was too slow to help.
I don't recall whether both Gerry and Gersh Budker were at the 1959 CERN conference or if so they discussed it there, but the next chance would have been in 1963 at the Dubna Conference and at Novosibirsk afterwards. Gerry, Arnold Schoch, about ten others and I visited the INP (now BINP) after the conference. On the flight back to Moscow, I was accompanied by Igor Meshkov who built the first electron cooling system for NAP. Igor had built an electron gun-collector system but had discovered that space charge caused the effective beam temperature to increase too rapidly. Three years ago Igor reminded me that I had suggested immersing the beam in a magnetic field to control it. (I had extensively studied electron beam formation and propagation when I designed and built the injector for the 50 MeV FFAG at MURA.) Thus electron cooling was already under way experimentally and theoretically (Sagdeev et al.) at INP in 1963. Budker then gave his paper at the Orsay Conference in 1966.
Since they are both deceased, we cannot ask them who came first. My own view is that while the Princeton bunch fiddled with an idea and dropped it, INP under Budker, with Meskov and Dikansky, built and tested the system which proved the method. In fact, Budker built his whole laboratory to accommodate 25 GeV p-pbar collisions, which doesnąt work without cooling. He deserves to be called the inventor."
8/66, Design Study for a Muon and Antiproton Facility at SLAC, F. Lobkowicz, D. Green and S. Serio, UR-875-161 (Aug. 10, 1966). A continuation of the paper by Tinlot and Green. It is stated on p. 25 that there is no transverse damping mechanism for the stored muon beam. That is, ionization cooling was not considered here.
5/65, On the Oscillation Decrements in Accelerators in the Presence of Arbitrary Energy Losses, A.A. Kolomenskii, Sov. Atomic Energy 19, 1511 (1965). The first Russian analysis of ionization cooling.
3/65, A Storage Ring for 10 BeV/c Muons, J. Tinlot and D. Green, UR-875-76 (March 10, 1965). The ring is also called a `trap`. Its purpose is to perform muon-nucleus scattering experiment off internal targets at SLAC. John Tinlot died in Sept. 1965.
60, An unpublished note, A.C. Melissinos (1960). Perhaps the first written discussion of a muon storage ring. The purpose of the ring was to produce a pure, extracted muon beam (no pions), that would be used as a source of neutrinos for the famous BNL 2-neutrino experiment.
7/56, Modification of Liouville's Theorem Required by the Presence of Dissipative Forces, D.B. Lichtenberg, P. Stehle and K.R. Symon, MURA-126, July 12, 1956. This paper expands on O'Neill's idea of ionization cooling (and does not mention wedge cooling). The paper concludes, however, that multiple scattering would mask any cooling effect.
4/56, Storage-Ring Synchrotron: Device for High-Energy Physics Research, G.K. O'Neill, Phys. Rev. 102, 1418 (1956). First published discussion of wedge cooling. When E. Wigner heard about this from O'Neill at tea one day (1955-56), he immediately commented that this process violates Liouville's theorem. F.C. Shoemaker believes that Wigner's remark was the first mention of the relevance of Liouville's theorem to accelerator physics. [See also MURA88, and footnote 3 of Kerst et al, Phys. Rev. 102, 590 (1956).] O'Neill then worked out that the primary effect of the wedge is a phase space exchange. But, the paper contains a line that indicates that O'Neill understood that an effect of ionization is that `the area in phase space available to a particle can be made to decrease with time.' This appears to be the genesis of ionization cooling. This paper is also O'Neill's first statement of the advantage of colliding beams over fixed-target in reaching high center of mass energies.

The MURA papers below are not concerned with either muons or cooling, but are the earliest records of the thoughts of Kerst and his immediate colleagues on the concept of colliding beams.
4/56, Properties of an Intersecting-Beam Accelerating System, D.W. Kerst, MURA-111 (April 26, 1956).
4/56, Intersecting Beam Accelerator with Storage Ring, D.B. Lichtenberg, R.G. Newton and M.H. Ross, MURA-110 (April 26, 1956).
1/56, Attainment of Very High Energy by Means of Intersecting Beams of Particles, D.W. Kerst et al., Phys. Rev. 102, 590 (1956).
12/55, Some Estimates of Properties of Intersecting Beam Accelerators, D.W. Kerst, MURA-88, DWK/13 (Dec. 3, 1955). Credits Wigner with having pointed out the importance of phase space to accelerator theory.
8/55, The Possibility of High Intensities from FFAG Accelerators Providing a Means of Increasing the Energy, D.W. Kerst, MURA-81, DWK/12 (Aug. 26, 1955). May be the first mention in writing of accelerators with colliding beams. Credits Symon and Sessler with having worked on these ideas in the preceding months.
6/54, On the Application of Very High Energy Machines, R.G. Sachs, MURA-38, RGS-1 (June 19, 1954).
9/53, A Study of the Feasibility of a Multi-BeV Circular Electron Accelerator, L.W. Jones and J. Laslett, MURA-6, LWJ-LJL/MAC-5 (Sep. 26, 1953). This and MURA-38 by Sachs lament the inefficiency of fixed-target accelerators in producing large center-of-mass energies, but do not appear to suggest colliding beams as an improvement.

9/98, Comments by Fred Mills: I first heard about "ionization cooling" in 1956 when I went to MURA. The "Piccione lip" on the extraction target, or foil, was well understood. It reduced the emittance of the beam (while increasing the momentum spread) in a process we now call "phase space exchange". Gerry O'Neill of Princeton proposed using this process to increase the luminosity (a term which had not yet been coined) of Storage Ring Colliders, (also not yet coined) which he invented at the same time as Don Lichtenberg and Roger Newton (we called them "Newton's Rings").

There was a disagreement, settled in a MURA Report 126 by Lichtenberg, Stehle and Symon, in which they showed the relationship between energy loss (of any type) and phase space reduction. I suppose this constitutes the "invention" of ionization cooling. Since the cooling required many strong interaction mean free paths, that ended that for hadrons. We of course knew it might work with muons, but that seemed a bit far off, if not far-fetched. At that time ANY collider seemed far-fetched to the HEP community, particularly one using particles from a secondary beam.

I might comment that Lichtenberg et al. missed the phase space exchange simply because they didn't include a change in the coordinate as well as the momentum in the generalized forces, nor did they consider individual projected phase spaces. This is shown in my 1963 NIM paper on radiation damping of electrons.

Just before Milt White died he cornered me (I was beginning to work on electron and stochastic cooling at Fermilab, he was president of URA) and told me about the origin of the electron cooling idea. At a faculty meeting Milt and Gerry were talking about how to reduce the emittance of the van der Graaff beam which was to be injected into the PPA. Lyman Spitzer suggested that they could do it by passing the proton beam along with an electron beam of the same velocity, but he pointed out that it was impractical because it would take too long a path. Gerry got a student working on it but never pursued it much further. I heard about this work at MURA in the 50's also. In Budker's first paper (Saclay, 1966) he states "this is an idea told to me by Gerry O'Neill". Of course Budker saw to the development of the theory and practice of electron cooling and deserves to be called its inventor. By the same standard, there is as yet no inventor of ionization cooling.

In 1956, after a Postdoc helping to make one of R.R. Wilson's machines work, I went to MURA where in one year I learned at least ten times as much as I had at Cornell. One year later, we effortlessly turned on the world's first spiral sector accelerator. I suggested to Don Kerst that we should send a letter to Phys. Rev. Don smiled and said that it would not be accepted. After I persisted, he agreed. The letter was turned down. I had to confront the fact that the field I was in had no legitimate means of publishing its work. Only in 1965 with the advent of the PAC (I was asked to be on its first committees, but sent someone else) was there any means of publication, even in a non-refereed form. NIM and RSI would take review articles occasionally...


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