Michael J. Tannenbaum
A.B. 1959, M.A. 1960, PhD 1965 Columbia

Senior Physicist
Brookhaven National Laboratory
E-mail:mjt@bnl.gov
Experimental Physics - from muons to gluons

Professional Experience and Curriculum Vitae

Publications

Research Overview

Columbia and CERN

In graduate school at Columbia, after summer jobs at Nevis, Los Alamos and Brookhaven, I became interested in the problem of ``why muons weigh heavy'' (compared to electrons)---was this somehow due to a force coupled to ``mu-ness''? My thesis, under the tutelage of Leon Lederman, was a measurement of muon-proton elastic scattering in comparison to electron-proton (e-p) scattering to see whether muons and electrons had different charge radii---they didn't [1]. I then went to CERN as a post-doc and worked with Jack Steinberger and Carlo Rubbia on the first measurement of K_S and K_L Interference in the pi+ pi- decay mode, which for K_L is CP violating [2]. I also worked with Francis Farley, Emilio Picasso, Simon van der Meer on the first storage ring measurement of g-2 of the muon [3].

Harvard: muons, photons, proposals

When I returned to the U.S. as an Assistant Professor at Harvard, I wrote a review article with Leon Lederman on High Energy Muon Scattering, which included a neat formalism for the design of longitudinally and transversely polarized muon beams [4,5]. This article further piqued my curiosity about the mass of the muon, and I thought of scattering muons from each other in hopes to see the force of mu-ness---the analogy being the strong force, which becomes apparent in hadron-hadron scattering but is absent in hadron-electron scattering. Of course, colliding beams of muons didn't (and still don't quite) exist, so I did the next best thing of using a muon to produce a pair of muons in the field of a nucleus, the muon trident [6]. No force of mu-ness appeared, but we were able to observe for the first time the Fermi statistics of identical muons [7]. With the presence of the Cambridge Electron Accelerator (CEA) at Harvard, John Russell and I and 3 graduate students made measurements of vector meson, inclusive pion and recoil proton photoproduction using a tagged photon beam [8]. The missing mass technique we employed in the CEA experiment proved useful in another muon experiment at the Brookhaven AGS, where we looked for excited muons by the same method---again no luck [9]. However, since deeply inelastic e-p scattering (DIS) experiments at SLAC had just indicated point-like structures inside the proton, we were the first to measure the Atomic Mass dependence of DIS in nuclear targets---showing that muons are much better for this purpose, since bremsstrahlung is suppressed---and found A to the power 1.00 for x>0.1 as expected from pointlike constituent scattering [10].

This was the time when NAL (now FERMILAB) was starting up, and every Assistant Professor worth their salt had submitted a few proposals. I was no exception: with Leon Lederman, to look for the fabled intermediate boson, W, by single lepton and lepton pairs (E70); deeply inelastic scattering by muons, with the Harvard group (P29, E98); and a search for heavy leptons and W bosons via photoproduction, with Wonyong Lee (E87). In the 1970 NAL summer study, where the the photoproduction proposal with Wonyong was developed, I started thinking about how the high energy tail of a photon beam could be enhanced above the 1/k bremsstrahlung spectrum---this led me to the idea of the ``coherently hardened photon beam'' which works better, the higher the energy [11]. I also derived (to my surprise) a characteristic peaking at low energy in the spectrum of muo-produced direct e+ e- pairs which is qualitatitively different than the spectrum from direct coulomb production of equal or heavier mass pairs---this was confusing to me at the time, but the effect turned out to be well-known. I finished this work 20 years later when energy loss of relativistic muons became an important issue for the SSC and LHC [12], and direct pair production in Au+Au collisions became an important issue for RHIC [13].

Rockefeller: collider physics at the CERN ISR

I never got to do any of the experiments at NAL because I went to Rockefeller University in 1971, just at the time when Rod Cool---who had recently started the Rockefeller group---and Leon Lederman found ``high p_T'' pion production at the new CERN ISR. This was another crucial indication of pointlike structure in the proton---a major discovery which proved that the partons of DIS were strongly interacting. I went to CERN, in 1973, to follow this up, and participated in a series of experiments (CCRS, CCOR, [B]C[M]OR) which made several important discoveries and innovations in the study of ``high transverse momentum phenomena'' in p-p collisions: direct leptons (later found to be due to `open charm' [14]; inverse 5th power p_T scaling at fixed x; demonstration that high p_T pions are produced by states with two roughly back-to-back jets and measurement of the jet properties; conversion method for direct photons; systematics of di-lepton production; first measurement of the constituent-scattering angular distribution (using pion-pairs) [15]---all in agreement with QCD. Ok, so we didn't discover the J/Psi and the Upsilon, but we were close; we got beat (twice!) by lower energy machines with higher luminosities. I guess this is what precipitated my move to BNL in 1980, to `help save' ISABELLE which would have been the highest energy machine with the highest luminosity.

BNL: First ISABELLE, then the ISR

Two years of making superconducting accelerator magnets proved to be a very interesting intellectual challenge, which also led to a quantitative understanding of two important issues [16]: the superconductor critical current and its relationship from strand to cable to magnet; and the magnetic properties of iron laminations at room temperature and 4.2 K. With the cancellation of ISABELLE in favor of the TEVATRON and the SSC, I started thinking about polarized p-p collisions as a still unexplored domain where new tools (parity violation) could lead to the discovery of new, unexpected phenomena---a topical example from Snowmass '82 being parity-violating quark-substructure. I resumed research at the CERN ISR, and I became very interested in the shape of E_T spectra in p-p and alpha-alpha collisions after we measured them to be the same over 10 orders of magnitude in cross section [17]. During this period, arguments raged about how or whether experiments could be done in open geometry at high luminosity. Following the work of Randy Johnson, I began to understand the importance of convolutions when considering E_T spectra from several piled-up p-p collisions. I then applied this concept to E_T spectra from alpha-alpha collisions. With the help of Chellis Chasman and John Olness, this led me to the use of gamma distributions for E_T spectra, both because of their convolution property and the fact that they happened to describe the spectra to an incredible degree[17].

BNL: Relativistic Heavy Ion Physics

Rising like a phoenix from the debris of ISABELLE, a new facility for research was created at BNL by the construction in 1984-85 of a transfer line between the Tandem and the AGS to allow the acceleration of heavy ions in the AGS for fixed target experiments, possibly leading up to a Relativistic Heavy Ion Collider (RHIC) in the ISABELLE tunnel. Based on the ISR alpha-alpha results, and to exploit the new state of nuclear matter at conditions of extreme temperature and density which would be produced, I joined with Ole Hansen, Chellis Chasman, Lee Grodzins, Shoji Nagamiya and others in an experiment (E802) to explore all aspects of these relativistic heavy ion collisions---one of the few examples of `applied high energy physics'. This has been very fruitful and continues to be one of my main occupations. As a complement to the beautiful data on the systematics of semi-inclusive identified particle production in p+A, O+A, Si+A and Au+Au collisions [18], this experiment allowed me to continue the study of shapes of E_T spectra, gamma distributions and convolutions, which resulted in a clear understanding of the `Global Variables' in these reactions [19,20]---including the explanation of intermittency by using Negative Binomial Distribution fits to the shape of multiplicity distributions in small angular intervals to reveal a dramatically reduced correlation length in central O+Cu collisions [21], consistent with Bose-Einstein correlations of identical particles.

Present Research: PHENIX and RHIC/SPIN

The approval of RHIC, in January 1990, led eventually, in 1991, to a new PHENIX---this time an experiment to study leptons, photons and hadrons at RHIC---which arose from the combination of three competing but rejected proposals. In a parallel time-frame, a BNL task force for ``Polarized Protons at RHIC''---with myself and Gerry Bunce as co-leaders---was revived. This led to a proposal for a program of Spin Physics using the Heavy Ion detectors at the RHIC polarized collider [22], and, eventually, to the agreement, in 1995, for the BNL-RIKEN RHIC/Spin program---which provides for a polarized-proton program at RHIC to complement the Relativistic Heavy Ion program. The PHENIX experiment at RHIC is now my main effort. Many of the essential concepts in PHENIX are the result of my experience from the CERN-ISR: the need for an electron trigger for low pT e+ or e- (e.g. for the J/Psi or low mass pairs) utilizing a Calorimeter and a Cerenkov counter with as little material in the aperture and no-magnetic field on the axis to avoid curling up the lower energy member of internal or external conversions [23]; use of internal conversions with mass above pizero to measure direct photons at low pT[24]; the use of direct (non-photonic) single electrons as a charm signal [24] including the converter method for a precision measurement of non-photonic background; highly segmented EM calorimeter to be able to separate photons from pizeros to 25 GeV/c[25]; single-inclusive and two-particle measurements as the only way to measure hard-scattering and jets in heavy ion collisions[26]; x_T scaling as a test of QCD[27]; use of Gamma Distributions to study and understand Fluctuations [28]. These methods led to major discoveries by PHENIX such as observation of suppression of pizeroes [25] and non-suppression of direct photons in A+A collisions [29] as evidence for the discovery of a strong medium effect [30], first measurements of charm and J/Psi at RHIC, properties of jets in p-p [31] d+Au and Au+Au collisions, measurement of ET distributions and fluctuations [32] , observation of anomalous antiproton to pion ratio (still unexplained) at intermediate pT (2 to 4.5 GeV/c)[33], suppression of direct-single-electrons from heavy quarks comparable to suppression of pizero for pT ~ 5 GeV/c [34]. There are so many discoveries that I wrote a review article to summarize them [35]. Still unexplored are the Gluon structure functions in nuclei and spin-structure function in polarized p-p collisions using direct photon production; search for new physics using parity violation in ~100 GeV jets, measurements of flavor-identified structure functions using parity violating W production. Also remaining to be understood are the detailed mechanism of suppression of both light and heavy quarks at RHIC and the properties of the highly opaque medium produced in Au+Au collisions. Understanding these issues ensures an exciting research program for the forseeable future.

Some Representative Publications

  1. R.Cool, A.Maschke, L.M.Lederman, M.J.Tannenbaum, R.Ellsworth, A.Melissinos, J.H.Tinlot and T.Yamanouchi, Muon-Proton Scattering at High Momentum Transfers, Phys. Rev. Letters, 14, 724(1965); Michael J. Tannenbaum, thesis, Columbia University, Nevis-132 (1965).
  2. C.Alff-Steinberger, W.Heuer, K.Kleinknecht, C.Rubbia, A.Scribano, J.Steinberger, M.J.Tannenbaum and K.Tittel, K_S and K_L Interference in the pi+ pi- Decay Mode, CP Invariance and the K_S - K_L Mass Difference , Phys. Lett. 20, 207 (1966).
  3. F.J.M.Farley, J.Bailey, R.C.A.Brown, M.Giesch, H.Jostlein, S.vanderMeer, E.Picasso and M.J.Tannenbaum, The Anomalous Magnetic Moment of the Negative Muon , Nuovo Cimento 45A, 281 (1966).
  4. L.M.Lederman and M.J.Tannenbaum, High Energy Muon Scattering, in Advances in Particle Physics, Volume 1, Eds. R.L.Cool and R.E.Marshak, Interscience, New York (1968).
  5. My formula for the muon beam polarization is still in use: See Eq.2 in Spin Muon Collaboration, B.Adeva, et al., Nucl. Inst. Meth. A343, 363 (1994).
  6. Michael J. Tannenbaum, Muon Tridents, Phys. Rev. 167, 1308 (1968).
  7. J.J.Russell, R.C.Sah, M.J.Tannenbaum, W.E.Cleland, D.G.Ryan and D.G.Stairs, Observation of Muon Trident Production in Lead and the Statistics of the Muon, Phys. Rev. Lett. 26, 46 (1971).
  8. G.E.Gladding, J.J.Russell, M.J.Tannenbaum, J.M.Weiss and G.B.Thomson, Measurement of Photoproduction of omega and rho Mesons in Hydrogen, Phys. Rev. D8, 3721, 3735 (1973).
  9. H.Gittelson, T.Kirk, M.Murtagh, M.J.Tannenbaum, A.Entenberg, H.Jostlein, I.Kostoulas, A.C.Melissinos, L.M.Lederman, P.Limon, M.May, P.Rapp, J.Sculli, T.White and T.Yamanouchi, Search for Excited Muons, Phys. Rev. D10, 1379 (1974).
  10. M.May, E.Aslanides, L.M.Lederman, P.Limon, P.Rapp, A.Entenberg, H.Jostlein, I.J.Kim, K.Konigsman, I.G.Kostoulas, A.C.Melissinos, H.Gittelson, T.Kirk, M.Murtagh, M.J.Tannenbaum, J.Sculli, T.White and T.Yamanouchi, Scattering of 7-GeV Muons in Nuclei, Phys. Rev. Lett. 35, 407 (1975).
  11. Michael J. Tannenbaum, Features of Possible Polarized Photon Beams at High Energy---The Coherently Hardened Bremsstrahlung Beam, Proc. of 1980 Interntaional Symposium on High Energy Physics with Polarized Beams and Polarized Targets, (Birkhauser, Basel, 1980),pp 379-388; A High Energy High Intensity Coherent Photon Beam for the SSC, Proc of the SSC Fixed Target Workshop, P. McIntyre ed., The Woodlands TX (1984).
  12. M.J.Tannenbaum, Simple formulas for the energy loss of ultrarelativistic muons by direct pair production, Nucl. Inst. Meth. A300, 595 (1991); M.J.Tannenbaum, Inelastic Scattering, the Virtual Radiator and Energy Loss by Relativistic Muons , 1970 Summer Study, NAL, Batavia, IL, pp. 231-239.
  13. Proceedings of the Workshop, ``Can RHIC be used to test QED?'', Eds. M.Fatyga, M.J.Rhoades-Brown, M.J.Tannenbaum, April 20-21, 1990, BNL-52247 (1990).
  14. CERN-Columbia-Rockefeller-Saclay (CCRS) Collaboration, F.W.Busser, L.Camilleri, L.DiLella, B.G.Pope, A.M.Smith, B.J.Blumenfeld, S.N.White, A.F.Rothenberg, S.L.Segler, M.J.Tannenbaum, M.Banner, J.B.Cheze, H.Kasha, J.P.Pansart, G.Smadja, J.Teiger, H.Zaccone and A.Zylberstejn, A Measurement of Single Electrons, Electron Pairs, and Associated Phenomena, in Proton-Proton Collisions at the CERN ISR, Nucl. Phys. B113, 189 (1976).
  15. CERN-Columbia-Oxford-Rockefeller (CCOR) Collaboration, A.L.Angelis, H.-J,Besch, B.J.Blumenfeld, L.Camilleri, T.J.Chapin, R.L.Cool, C.delPapa, L.DiLella, Z.Dimcovski, R.J.Hollebeek, L.M.Lederman, D.A.Levinthal, J.T.Linnemann, C.B.Newman, N.Phinney, B.G.Pope, S.H.Pordes, A.F.Rothenberg, R.W.Rusak, A.M.Segar, J.Singh-Sidhu, A.M.Smith, M.J.Tannenbaum, R.A.Vidal, J.S.Wallace-Hadrill, J.M.Yelton and K.K.Young, Determination of the Angular and Energy Dependence of Hard Constituent Scattering from pizero Pair Events at the CERN Intersecting Storage Rings, Nucl. Phys. B209, 284 (1982).
  16. E.J.Bleser, J.G.Cottingham, P.F.Dahl, R.J.Engelmann, R.C.Fernow, M.Garber, A.K.Ghosh, C.L.Goodzeit, A.F.Greene, J.C.Herrera, S.A.Kahn, J.Kaugerts, E.R.Kelly, H.G.Kirk, R.J.Leroy, G.H.Morgan, R.B.Palmer, A.G.Prodell, D.C.Rahm, W.B.Sampson, R.P.Shutt, A.J.Stevens, M.J.Tannenbaum, P.A.Thompson, P.J.Wanderer and E.H.Willen, Superconducting Magnets for the CBA Project, Nucl. Inst. Meth. A235, 435 (1985); M.J.Tannenbaum, M.Garber and W.B.Sampson, Correlation of Superconductor Strand, Cable and Dipole Critical Currents in CBA Magnets, IEEE Trans. Magnetics, Mag-19, 1357 (1983); M.J.Tannenbaum, A.K.Ghosh, K.E.Robins and W.B.Sampson, Magnetic Properties of the Iron Laminations for CBA Magnets, IEEE Trans. Nucl. Sci., NS-30, 3472 (1983).
  17. BNL-CERN-Michigan State-Oxford-Rockefeller (BCMOR) Collaboration, A.L.S.Angelis, G.Basini, H.J.Besch, R.E.Breedon, L.Camilleri, T.J.Chapin, C.Chasman, R.L.Cool, P.T.Cox, Ch.von Gagern, C.Grosso-Pilcher, D.S.Hanna, P.E.Haustein, B.M.Humphries, J.T.Linnemann, C.B.Newman-Holmes, R.B.Nickerson, J.W.Olness, N.Phinney, B.G.Pope, S.H.Pordes, K.J.Powell, R.W.Rusack, C.W.Salgado, A.M.Segar, S.R.Stampke, M.Tanaka, M.J.Tannenbaum, P.Thieberger and J.M.Yelton, Observation of KNO Scaling in The Neutral Energy Spectra from alpha-alpha and p-p Collisions at ISR Energies, Phys. Lett. 168B, 158 (1986).
  18. E802 Collaboration, ANL - BNL - UCBerkeley - UCRiverside - Columbia - Hiroshima - INS - Kyushu - LBL - MIT - Tokyo, T.Abbott, Y.Akiba, D.Alburger, D.Beavis, P.Beery, R.R.Betts, M.A.Bloomer, P.D.Bond, C.Chasman, Z.Chen, Y.Y.Chu, B.A.Cole, J.B.Costales, H.J.Crawford, J.B.Cumming, R.Debbe, E.Duek, H.A.Enge, J.Engelage, S.Y.Fung, D.Greiner, L.Grodzins, S.Gushue, H.Hamagaki, O.Hansen, P.Haustein, S.Hayashi, S.Homma, H.Z.Huang, Y.Ikeda, J.Kang, S.Katcoff, S.Kaufman, R.J.Ledoux, M.J.Levine, P.J.Lindstrom, M.Mariscotti, Y.Miake, R.J.Morse, S.Nagamiya, J.Olness, C.G.Parsons, L.P.Remsberg, H.Sakurai, M.Sarabura, A.Shor, R.Seto, S.G.Steadman, G.S.F.Stephans, T.Sugitate, A.W.Sunyar, M.Tanaka, M.J.Tannenbaum, M.Torikoshi, J.H.vanDijk, F.Videbaek, M.Vient, P.Vincent, E.Vulgaris, V.Vutsadakis, W.A.WatsonIII, H.E.Wegner, D.S.Woodruff, and W.A.Zajc, Kaon and pion production in central Si+Au collisions at 14.6 A GeV/c, Phys. Rev. Lett. 64, 847 (1990); Bose-Einstein correlations in Si+Al and Si+Au collisions at 14.6 A GeV/c, Phys. Rev. Lett. 69, 1030 (1992).
  19. E802 Collaboration, T.Abbott, et al., Measurement of energy emission from O+A and p+A collisions at 14.5 GeV/c per nucleon with a lead--glass array, Phys. Lett. B197, 285 (1987).
  20. M.J.Tannenbaum, Transverse Energy Production in Light and Heavy Ion Interactions, Intl. J. Mod. Phys. A4, 3377 (1989).
  21. E802 Collaboration, T.Abbott, et al., Multiplicity distributions from central collisions of O+Cu at 14.6 A GeV/c and intermittency, Phys. Rev. C52, 2663 (1995).
  22. G.Bunce, J.Collins, S.Heppelmann, R.Jaffe, S.Y.Lee, Y.Makdisi, R.W.Robinett, J.Soffer, M.Tannenbaum, D.Underwood and A.Yokosawa, Polarized Protons at RHIC, Particle World 3, 1 (1992).
  23. M. J. Tannenbaum, Lepton and Photon Physics at RHIC, Proc. 7th Workshop on Quantum Chromodynamics, La Citadelle, Villefranche-sur-Mer, France, January 6-10, 2003, Eds. H.M.Fried, B. Muller, Y. Gabellini (World Scientific, Singapore, 2003) pp 25-38, arXiv:nucl-ex/0406023
  24. M. J. Tannenbaum, Charm in PHENIX-- a Signal or a Background?, Heavy Ion Physics 4, 139-148 (1996)
  25. PHENIX Collaboration, K. Adcox, et al., Suppression of Hadrons with Large Transverse Momentum in Central Au+Au Collisions at √sNN=130 GeV, Phys. Rev. Letters 88, 022301 (2002); S. S. Adler, et al., Midrapidity Neutral-Pion Production in Proton-Proton Collisions at √s=200 GeV , Phys. Rev. Letters 91, 241803 (2003); Suppressed π0 Production at Large Transverse Momentum in Central Au+Au collisions at √sNN=200 GeV, Phys. Rev. Letters 91, 072301 (2003)
  26. M. J. Tannenbaum, From the ISR to RHIC--measurements of hard-scattering and jets using inclusive single particle production and 2-particle correlations , Journal of Physics: Conference Series 27, 1-10 (2005)
  27. PHENIX Collaboration, S. S. Adler, et al., High-pT charged hadron suppression in Au+Au collisions at √sNN=200 GeV , Phys. Rev C 69, 034910 (2004)
  28. M. J. Tannenbaum, The distribution function of the event-by-event average pT for statistically independent emission , Phys. Lett. B 498, 29-34 (2001) ---``It's not a gaussian it's a gamma distribution.''
  29. PHENIX Collaboration, S. S. Adler, et al, Centrality Dependence of Direct Photon Production in √sNN=200 GeV Au+Au Collisions, Phys. Rev. Letters 94, 232301 (2005)
  30. PHENIX Collaboration, K. Adcox, et al., Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX Collaboration, Nucl. Phys. A 757, 184-283 (2005)
  31. PHENIX Collaboration, S. S. Adler, et al., Jet properties from dihadron correlations in p+p collisions at √s=200 GeV , Phys. Rev. D 74, 072002 (2006)
  32. PHENIX Collaboration, K. Adcox, et al., Measurement of the Midrapidity Transverse Energy Distribution from √sNN=130 GeV Au+Au Collisions at RHIC, Phys. Rev. Letters 87, 052301 (2001); S. S. Adler, et al., Measurement of Nonrandom Event-by-Event Fluctuations of Average Transverse Momentum in √sNN=200 GeV Au+Au and p+p Collisions, Phys. Rev. Letters 93, 092301 (2004)
  33. PHENIX Collaboration, S. S. Adler, et al., Scaling Properties of Proton and Antiproton Production in √sNN=200 GeV Au+Au Collisions, Phys. Rev. Letters 91, 172301 (2003)
  34. PHENIX Collaboration, S. S. Adler, et al., Nuclear Modification of Electron Spectra and Implications for Heavy Quark Energy Loss in Au+Au collisions at √sNN=200 GeV, Phys. Rev. Letters 96, 032301 (2006), ibid 032001
  35. M. J. Tannenbaum, Recent results in relativistic heavy ion collisions: from `a new state of matter' to `the perfect fluid', Rep. Prog. Phys. 69, 2005-2059 (2006)
Recent Talks and Publications on the WWW
| PHENIX Collaboration Meeting Jan 8-12, 1996 | Multiplicity Fluctuations |
| Convolutions/Intermittency | RHIC/Spin-95 | RHIC/Spin-96 | Charm in PHENIX |
| How to discover the Quark Gluon Plasma | BNL/PHENIX Group WWW page |
| MJT PHENIX-Publish Page |
PHENIX Links
| PHENIX Home Page | BNL/PHENIX Group | Electron Working Group | RHIC/Spin/Collaboration |
| Hard Scattering Working Group | RIKEN/BNL Spin | RHIC/Spin/Accelerator | Nina's View |
Michael J. Tannenbaum 07/01/2010 - contact: mjt@bnl.gov